Progress 02/14/02 to 02/13/07
Outputs
Progress Report Objectives (from AD-416) Develop user acceptable protocols for assessing spatial variability of crop prod. parameters, including water, soil, nitrogen, & weeds at field scale using remote sensing & sensor tech; Evaluate & develop assessment tools to determine potential benefits to crop prod., water quan. & qual.; Dev. mgmt. tools that enable producers to readily implement precision ag. tech. for spatial & temporal appl. of water, nutrients, & pesticides; Eval. & improve performance of commercial variable rate chemical application equipment. Approach (from AD-416) This is a multi-disciplinary project with the vision to determine the benefits of PF technology in the context of managing irrigated crop production to use water efficiently & minimize application of chemicals that can degrade our water resources. The project refocuses a cooperative project between WMU & producers, industry, CO State Univ. scientists & ARS ARS units, & builds on extensive baseline data collected on two center pivot irrigated fields. The goal is to determine the variability in yields & the changes in management inputs that are acceptable & beneficial to the producer. The National Res. Council (1997) emphasized that precision agric. needs dynamic experimentation to supersede trad. controlled experimental plots, thus the lack of a replicated plot design. We do not assume that variable rate technology (VRT) or SSM is appropriate for every field. The project is dynamic because specific studies are adjusted based on feedback from our focus group, cooperating farmers, industry, and other university partners. Accomplishments Improved statistical analysis for mapping site-specific pest management: Pest count data is analyzed with linear regression models to improve the ability to predict and map pest distributions for site-specific management. However, agricultural pests are most often in patches in fields and consequently, this use of linear regression models may lead to inaccurate methods for making pest maps and invalid conclusions about why pests occur in patches and where those patches may be within a field. We recommend using zero-inflated negative binomial regression models rather than linear regression models based on tests with weed count data. Analyzing pest count data with this previously untried model could lead to procedures and knowledge for more accurate methods to create pests maps. More growers will implement site-specific pest management to minimize pesticide use as the risk of crop yield loss from inaccurate pest maps is reduced. NP201: Problem area 2, Problem 7. Enhanced Atrazine Degradation: Enhanced degradation of atrazine, a herbicide commonly used for weed control in corn, has been documented in irrigated corn fields that had received multiple applications of the herbicide for 3 or more years. A study was done to determine if this same phenomenon was true for rainfed corn. Enhanced atrazine degradation was evident in rainfed fields that had received multiple applications of the herbicide. These results show that this phenomenon is not confined to irrigated fields in Colorado. Weed control will not be as good in these field after atrazine application due to the enhanced rate of degradation. NP201: Problem area 6, Problem 6. Technology Transfer Number of Active CRADAS and MTAS: 2 Number of Web Sites managed: 1 Number of Non-Peer Reviewed Presentations and Proceedings: 12 Number of Newspaper Articles,Presentations for NonScience Audiences: 4
Impacts
(N/A)
Publications
- Wiles, L., Bobbit, R., Westra, P. 2007. Site-Specific Weed Management in Growers' Fields: Predictions from Hand-drawn Maps. Chapter 5. In F. Pierce and D. Clay, eds. Applications of GIS for Agriculture, Volume I,CRC Press
- Shaner, D.L., Stidham, M.A., Singh, B.K. 2007. Imidazolinone herbicides. Book Chapter.
- Henry, W.B., Shaner, D.L., West, M.S. 2007. Shikimate accumulation in sunflower, wheat, and proso millet after glyphosate application. Weed Science 55:1-5.
- Shaner, D.L., Henry, W.B. 2007. Field History and Dissipation of Atrazine and Metolachlor in Colorado. Journal of Environmental Quality. Volume 36:pp 128-134
- Shaner, D.L., Belles, D., Westra, P., Brunk, G. 2006. Comparison of efficacy, absorption, and translocation of two glyphosate formulations in velvetleaf (Abutilon theophrasti). Pest Management Science.62:1177-1181
- Shaner, D.L., Henry, W.B., Krutz, L.J., Hanson, B.D. 2007. Rapid assay for detecting enhanced atrazine degradation in soil. Weed Science.Volume 55:528-535
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Progress 10/01/05 to 09/30/06
Outputs
Progress Report 1. What major problem or issue is being resolved and how are you resolving it (summarize project aims and objectives)? How serious is the problem? Why does it matter? The major problem being addressed is how to minimize adverse environmental impacts from crop production systems while producing a reliable and safe food supply. Agricultural crop production has been identified as a major non-point source of water quality degradation because of contamination from pesticides and nitrates in groundwater resulting from excessive application of water, pesticides, and fertilizers. The National priority to provide an adequate supply of safe drinking water requires efforts to reduce quality degradation by various major water users. Increasing competition for land and water resources and increasing pressure to curtail or more closely regulate agricultural operations because of environmental concerns are forcing producers to consider alternative crop production
systems to continue in operation. Irrigation is a critical component of American agriculture since about 40% of the nation's total crop value is produced on the 15% of the cropland that is irrigated. Precision Farming (PF) is a management strategy that uses information technologies to bring data from multiple sources to bear on decisions associated with crop production. We are addressing the development of integrated systems that can analyze these data to recommend scientifically based management strategies and deliver site specific applications of water, fertilizers, and pesticides. Field sampling strategies, models and remote sensing technology for applying the right amount of water and fertilizer are being developed and evaluated. We are adapting sprinkler irrigation systems to apply chemicals such as fertilizers and pesticides when and where needed during the growing season. A multidisciplinary approach is necessary to get a better understanding of how various nutrient, water,
pest, and climatic factors affect yield variability. Our goal is to increase the scientific understanding of many of the interactions within the crop production system, so the appropriate data are analyzed correctly to make improved management decisions. Our approach is to study commercial fields rather intensively over a 5+ year period. Comparison of different scenarios will provide the basis for assessing the environmental impact and economic feasibility of PF. We are working with industry partners through CRADAs to develop and evaluate economical alternative data collection procedures to characterize soil and crop status as well as variable rate application technologies for water, fertilizers, and pesticides that are economically feasible for producers to use. If producers are to benefit from adopting PF, they must make significant capital investments in equipment and data collection activities as well as obtain the analytical expertise to translate the voluminous data into
improved management decisions. Generally, the science of interpreting and integrating the various kinds of PF data is not well understood and the environmental benefits that have been promised have not been well documented. Producers are not certain whether this new technology is technically or economically practical. Although preliminary PF research indicates herbicide use may be reduced 30-60% without affecting crop yield or quality, the economic feasibility should be carefully evaluated before producers make large capital investments for this and other PF management strategies. Water quality degradation and increase in water demand requires new knowledge and improved systems for using our water resources more efficiently to sustain production of high quality food and fiber. 2. List by year the currently approved milestones (indicators of research progress) 2002 Milestones 1. Collect and interpret soil electrical conductivity data. Completed evaluations will be used to train 5
customers to use the protocols and evaluations of customers maps will be completed. 2. Analyze water and nitrogen conservation potential with Precision Farming. Select appropriate simulation models to evaluate management impacts on the environment. Use model to evaluate multi-year impacts on several fields using calibrated model. Expand beyond nitrogen and water if success is achieved. 3. Use remote sensing to optimize irrigation/nitrogen management. Collect data and optimization technique with farmer practices. Field test on customer managed fields with a couple of crops. 4. Test through simulation, laboratory and field tests the uniformity of a commercial chemical application (accupulse) system. 2003 Milestones 1. Collect multi-spectral imagery of several fields and analyze to assess in-season variability. Develop/modify and field test protocols for collection of remote sensing data. Test protocols on several cooperators fields. 2. Refine sprinkler evaluation software to
meet NRCS and industry needs. Model to be enhanced for new applicators and for entire field evaluation. Test model with NRCS and industry. Consider updating standards for center pivot and linear move evaluations. 3. Develop irrigation/nitrogen scheduling prototype software. Establish criteria, develop and test prototype model. 4. Modify in conjunction with industry the accupulse system for variable application of chemicals with a center pivot irrigation system. 2004 Milestones 1. Assess variability of water and nitrogen application. Evaluate accuracy and usability of simulation processes versus baseline collected data. Develop simplified protocols for customers to allow field scale assessments for improved management. 2. Characterize spatial distribution of weed populations through the collection of weed and seed bank data. Analyze collected data to describe spatial and temporal dynamics of weed populations. 3. Improve site specific management for water and nitrogen to
manage limited water quantity and enhance water quality with economic benefits. Plot studies in commercial fields will be studied to evaluate management strategies and evaluate the economic impact of improved water and nitrogen management. 4. Develop irrigation/nitrogen scheduling prototype software. Establish criteria, develop and test prototype model. Upgrade model to include Nitrogen reflectance index. 5. Develop site specific weed management model to create variable application maps that can apply with accupulse system. 2005 Milestones 1. Evaluate use of EC maps to infer the spatial variability of texture, soil water properties, and pesticide binding and leaching potentials. Identify and map EC of fields with much different soil types to further assess potential for improving water and herbicide management. 2. Use active optical sensor and spectroradiometer to monitor canopy and plant N status of corn and potatoes. Evaluate mounting options of the active sensor on a center
pivot sprinkler system. Finish analysis of satellite data to compare with corn canopy N status. 3. Analyze multi-site, multi-year EC, yield, and plant biomass and canopy N status estimates from remotely sensed data to determine if in- season and end-of-season plant parameters correlate with soil property estimates from EC measurements. 4. Evaluate the potential value of using a detailed soil-water-crop computerized model (RZWQM) to simulate water, nitrogen, and herbicide movement in irrigated sandy soils. Initial efforts will concentrate on compiling the past six years of field data from Wiggins and Yuma, constructing model input data files, and calibrating RZWQM for the prevailing management and cropping systems. 5. Evaluate weed management zones based on soil mapping and weed distribution in fields. Develop maps on distribution of glyphosate- resistant weed populations in Colorado. Determine relationship(s) between soil texture and EC that are useful in predicting herbicide
behavior. Determine the relationship between frequency of herbicide use and degradation of the herbicide in irrigated corn. 6. Evaluate the utility of active sensors on field equipment for identifying presence/absence of weeds and spraying as needed. 7. Test RZWQM predictions on herbicide behavior in field with data collected on herbicide movement and dissipation from two different fields. 8. Enhance CPED for new applicators and for entire field evaluation. Do more comprehensive testing of the existing model with NRCS and industry. 9. Quantify herbicide efficacy dissipation and leaching potential under field conditions, coupled with detail laboratory soil column studies to evaluate herbicide behavior under varying management. 10. Upgrade the prototype irrigation and nitrogen scheduling program to include a nitrogen budget component and structured modularly in an object oriented language. 11. Explore with industry the addition of improved water management software as an integral
part of irrigation system controls including adding improved water measurement devices. 12. Continue evaluating the value/benefits of variable application using a specially modified high-clearance tractor applicator capable of applying chemicals and/or liquid fertilizer like a center pivot as well as a conventional ground applicator. 2006 Milestones 1. Evaluate robustness and reliability of an active optical sensing system for acquiring plant N status to manage in-season N applications on irrigated corn. Evaluate various sensor mounting options. 2. Analyze multi-site, multiyear EC, yield and in-season plant parameters estimated from canopy reflectance measurements to determine if in-season plant parameters correlate with soil property estimates from EC measurements. 3. Develop easy to use software to automatically estimate and map % green cover in digital images collected in fallow fields. The method to collect digital images has already been developed with images collected when
traveling 4 to 5 mph. 4. Begin updating standards for center pivot and linear move evaluations. 5. Investigate use of infrared thermometers mounted on a center-pivot sprinkler to detect plant water stress and its spatial extent in a commercial irrigated corn field. Evaluate various techniques requiring canopy temperature for potential management of limited water supplies. 6. WeedSite is a model that was developed for growers to estimate the benefits of postemergence site-specific weed management compared to uniform in irrigated corn fields. This model will be expanded for comparison of site-specific and uniform management of soil-applied herbicides. 7. Assess potential to reduce postemergence herbicide use with site- specific weed compared to uniform management. 8. Evaluate effectiveness of variable rate herbicide application based on EC zones in farmers' fields. 9. Determine impact of variable rate herbicide application on ground and surface water contamination based on
models and field measurements. 10. Continue design/modifications to high-clearance tractor for variable rate application of chemicals and field test for application uniformity. 11. Use the modified high clearance tractor on field plot studies, to compare the performance and efficacy of various application methods for nitrogen and pesticides. 4a List the single most significant research accomplishment during FY 2006. Weed maps are useful to monitor the effectiveness of weed control, detect new invasions, plan preventative weed management for following crops and use site-specific weed management to reduce herbicide use. Sophisticated methods to map weed populations are being developed with slow progress. We developed a system to map weed cover in fallow fields that is automated, inexpensive, easy to use and does not require expensive and complicated GIS, GPS or image analysis software. Our low cost system uses only readily available technology including a consumer digital camera and
GPS unit plus commercial software to map the location of images and software that we developed to estimate and map weed cover from digital images. We will be able to distribute our software for free. We have demonstrated that expensive and sophisticated technology is not always needed to map weeds in growers fields. 4b List other significant research accomplishment(s), if any. Atrazine, an herbicide that is applied to most of the corn grown in the U. S., rapidly dissipates in soil from fields in eastern Colorado that have received multiple treatments of the herbicide for a number of years. A rapid assay was developed to screen fields for enhanced degradation of atrazine. The accuracy of the assay was tested in several fields in eastern Colorado which have been under continuous corn for many years. In these fields, atrazine degraded rapidly and no herbicide could be detected by 30 days after application. Farmers should be able to use this assay to determine if atrazine will
degrade rapidly in their fields and will be able to change their weed management program if enhanced degradation of atrazine is detected. Application of nitrogen (N) fertilizer during the growing season in response to crop requirement is critical to minimize potential pollution and to improve nitrogen use efficiency. Two commercial active sensors were evaluated to determine their ability to detect the N status in irrigated corn. One sensor was nonresponsive to crop N whereas the other active sensor responded to imposed N treatments. This type of sensor lends itself to mounting on farm machinery due to its anytime-of-day operation to detect and signal a controller to apply N fertilizer based on crop need. 5. Describe the major accomplishments to date and their predicted or actual impact. The selection of herbicide resistant weed populations is increasing and there is a need to develop simple methods to determine if a weed population is resistant to certain herbicides so that an
effective weed management program can be implemented. We have developed relatively simple leaf disc assays for determining resistance to ALS inhibitors, photosynthesis inhibitors and glyphosate. These assays have been used successfully in the field to detect resistance in different weed populations. Whole-field EC data from three commercial center pivot fields in Colorado were collected for 1998-2003 and analyzed using GIS and statistical packages. These analyses found strong relationships between yield and soil electrical conductivity (EC), but the relationships between EC and various soil productivity factors, were needed to be useful for site-specific management. The implementation of variable rate herbicide application depends on finding a means to economically map soil variability in the field. Three significant results applicable to non- saline agricultural fields were found: 1) soil electrical conductivity maps are highly stable over time and do not require annual mapping,
2) soil electrical conductivity correlates strongly with texture (clay content), organic matter and soil water, and 3) the fields could be divided into herbicide binding zones based on soil EC, and subsequent sampling of areas of these fields that had not been previously sampled showed that we could predict herbicide binding with good accuracy. Field EC mapping provides a sound method of subdividing the field into yield response and soil management zones for the purpose of implementing variable-rate application of nutrients and pesticides to reduce input costs and enhance the environment. Spatial and temporal variability of soil nitrogen(N) supply in conjunction with temporal variability of plant N demand makes conventional N management difficult for site specific N applications. Soils in historically high and low yielding areas within a commercial center-pivot irrigated corn field in northeastern Colorado were sampled to determine NO3-N levels before and after the growing season to
evaluate effectiveness of in-season N management based on remotely sensed crop N assessment. Crop N status was assessed at least weekly during vegetative growth to determine when to apply N. Applications of N based on remote sensing were 180 lb/ac less than the adjacent producer practice in the high yield area and 109 lb/ac less in the low yield area. These significant reductions in N application amounted to $50.40/ac in the high yield area and $30.50/ac in the low yield area at 2001 prices for N fertilizer. Residual NO3-N in the crop root zone was reduced by 117 lb/ac in the high yielding area and remained at similar levels for the low yielding area. In-season N application was reduced based on crop "need" while not reducing grain yield, and crop root zone soil NO3-N levels were reduced which minimizes potential N leaching and degradation of the environment. The efficient application of chemicals is a challenge for farmers to maintain an economical production system while being
good environmental stewards. Field studies with water sensitive paper have shown the coverage uniformity of AccuPulseTM to be comparable to conventional ground application and superior to aerial application. In many high value crops, fungicides that leave a chemical residue on leaves for disease protection, are applied multiple times either by air or chemigation. For chlorothalonil, a widely used fungicide on potatoes, foliage treated with AccuPulse had shown a 10 fold increase in residue compared to chemigation. Futhermore, the concentration of fungicide remaining on the leaves 7 days after application was greater on plants treated with AccuPulse, than on leaves 1 day after treatment with chemigation. These results suggest that farmers can significantly reduce the number of applications of fungicides by utilizing AccuPulse while still maintaining efficacy for controlling diseases. Data has been analyzed and a manuscript is near completion for determining the spatial uniformity
in 2D of the AccuPulse chemical application system. Replicated plot studies were done within the cooperating farmer's field for two years, to determine whether yields in historically low yielding areas could be substantially increased by more intensive water and nitrogen management that minimized any water or nitrogen stress to the crop. Historical yield data were used to identify low (>=15% below mean), average, and high (>=15% above mean) productivity areas. In the first year, there was a 15% increase in corn yield in the low productivity area when supplemental water and nitrogen were applied to insure there was no water or nitrogen stress. In the second year, there was a 10% increase in potato yields in the low production area when 15% additional water was applied to relieve water stress between farmer-managed irrigations. Potato yields were not decreased when the farmer practice of applying 90 lbs/ac of preplant nitrogen was omitted for a savings of $20.00 /ac in reduced
fertilizer costs. These results indicate water is a significant factor affecting yield, but the additional cost of improved management and application technology probably limits the economic feasibility of adoption. Site-specific weed management is a technique for controlling weeds in crops with less herbicide by mapping the weed population in a field and then treating only the areas of a field where control is economically justified and varying management for the most efficient control when the species present varies within a field. However, growers cannot adopt this strategy until 1) they are confident that the benefits of site-specific weed management will exceed the costs, and 2) they have cost effective methods to make weed maps. Our research addresses both these obstacles so site-specific weed management can become a cost-effective method for growers to control weeds with less herbicide. 1) The benefits of site- specific weed management vary with both the distribution of
weeds in a field and the site-specific strategy used. We have developed software for growers to investigate the potential benefits of postemergence site- specific weed management in their irrigated corn fields. The software predicts the outcome of uniform and 4 different site-specific management strategies based on hand drawn weed maps. 2) In cooperation with a private company, we designed and are testing a low cost package (<$4000) of commercially available software and hardware for making weed maps. Our design is a digital camera mounted on a tractor or ATV with automated analysis of digital images to create a map of weed cover within a field. Growers and agricultural consultants need models to predict changes in the number, species and distribution of weeds in cropped fields in response to management so they can anticipate and mitigate weed problems that may be created by using new weed management technologies. WISDEM is model developed by the ARS for this purpose. Scientists of
the ARS Water Management Research Unit, Colorado State University and a private crop protection company, are modifying WISDEM to predict potential weed problems from use of herbicide resistant crops. They have developed expert opinion that can be used in lieu of missing and costly data on weed biology required by the model and are improving the model's interface for use by growers and agricultural consultants. With these changes, WISDEM can become a means to help safeguard and improve critical tools for cost-effective and environmentally sound weed management. Atrazine, an herbicide that is applied to most of the corn grown in the U.S., appears to rapidly dissipate in soil from fields that have received multiple treatments of the herbicide for a number of years. A rapid assay was developed to screen fields for enhanced degradation of atrazine. The accuracy of the assay was tested in several fields in eastern Colorado which have been under continuous corn for many years. In these
fields, atrazine degraded rapidly and no herbicide could be detected by 30 days after application. Farmers should be able to use this assay to determine if atrazine will degrade rapidly in their fields and will be able to change their weed management program if enhanced degradation of atrazine is detected. We developed a system to map weed cover in fallow fields that is automated, inexpensive, easy to use and does not require expensive and complicated GIS, GPS or image analysis software. Weed maps are useful to monitor the effectiveness of weed control, detect new invasions, plan preventative weed management for following crops and use site-specific weed management to reduce herbicide use. Sophisticated methods to map weed populations are being developed with slow progress. Our low cost system uses only readily available technology including a consumer digital camera and GPS unit plus commercial software to map the location of images and software that we developed to estimate and map
weed cover from digital images. We will be able to distribute our software for free. We have demonstrated that expensive and sophisticated technology is not always needed to map weeds in growers fields. Two commercially available active sensors that provide their own light source and a research grade passive system that requires sunlight to illuminate the crop canopy were evaluated for assessment of crop nitrogen status of irrigated corn. One active sensor was essentially nonresponsive to the crops nitrogen content whereas the other active sensor responded to imposed nitrogen treatments. Its response was similar to the well-tested passive system. Analysis of a reflectance-based index to assess the nitrogen status of an irrigated corn crop showed excellent agreement between soil variations in a field determined by soil electrical conductivity for two years of data at a site in eastern Colorado with highly variable soils. Programs were written to control site-specific application of
nitrogen, herbicides, and pesticides with a modified high-clearance tractor based on maps generated from data describing when and where these chemicals were required in a given field. Testing showed inadequate measurement of flow to compensate for ground speed variations during chemical application. Refinements in pump capacity and flow measurement hardware are required. Hardware was designed and constructed to mount infrared thermometers on a center-pivot sprinkler to assess severity of plant water stress in irrigated corn and its spatial extent in a commercial corn field. Evaluation of the Water Deficit Index using canopy temperature monitored from an oblique view shows potential for improving its use during early vegetative growth in corn. Software development and testing for retrieval of soil moisture data at remote sites via radio telemetry and cell phone was completed. 6. What science and/or technologies have been transferred and to whom? When is the science and/or technology
likely to become available to the end- user (industry, farmer, other scientists)? What are the constraints, if known, to the adoption and durability of the technology products? Presented seminar at major university and participated in two university workshops on herbicide resistance management. Participated in workshop with major agro-chemical company on utility of a new plant growth regulator for maintaining crop yield under drought conditions. Participated in two workshops with growers on herbicide-soil interactions and how these interactions affect herbicide activity and dissipation. Invited presentations on the benefits of different strategies of site- specific postemergence weed management and in-season nitrogen management of sprinkler irrigated corn in commercial fields using ground-based remote sensing were given to practitioners at the 8th International Conference on Precision Agriculture in the Practitioner A-Z Track sessions. Invited presentation on in-season nitrogen
management using active sensors at field day held in Yuma, CO which was attended by producers and action agency personnel. Presentations on selection and evaluation of irrigation systems were given at Irrigation Water Management training for technical personnel at NRCS field offices. 7. List your most important publications in the popular press and presentations to organizations and articles written about your work. (NOTE: List your peer reviewed publications below). The units research on methods for more cost-effective weed management with precision agriculture technology was described in the August ARS Magazine. The article described a system to map weed populations in dryland crops, software to evaluate the benefits of site-specific weed management in irrigated corn and a method to reduce the cost of mapping to prescribe variable rate application of soil-applied herbicides. Scientific Meeting Presentations: Bausch, W.C. 2006. Comparison of active and passive optical sensors for
assessment of plant nitrogen. 8th International Conference on Precision Agriculture, Minneapolis, MN. Bausch, W.C. 2006. Canopy temperature view angle affects on the Water Deficit Index. ASABE Annual International Meeting, Portland, OR. Shaner, D. L., G. Brunk, S. Nissen and P. Westra. 2006. Adsorption and degradation of mesotrione in four soils. Western Society of Weed Science Annual Meeting, Reno, NV. Shaner, D. L., and W. B. Henry. 2006. Field history and dissipation of atrazine and metolachlor in Colorado. Weed Science Society of America Annual Meeting, New York, NY. Wiles, L. Site-specific Weed Management: Myth or Magic NSF-ADVANCE Distinguished Lecture Series. Kansas State University. March 8, 2006. Wiles, L., B. Waltermire, T. Giles and R. Bobbitt. Mapping Weed Presence in Dryland Crops. Eighth International Conference on Precision Agriculture. Abstract and Poster.
Impacts
(N/A)
Publications
- Bausch, W.C., Diker, K., Paris, J.F., Khosla, R. 2004. Estimating plant nitrogen status in irrigated corn using ground-based and satellite data. International Conference on Precision Agriculture Abstracts & Proceedings. . In Proc. of the 7th Intern. Conf. on Precision Agriculture. CD-ROM. Minneapolis, MN: ASA, CSSA, SSSA. (Conference proceedings)
- Shaner, D.L. 2004. Precision Weed Management: The wave of the future or just a passing fad?. Phytoparasitica. 32:107-110
- Bausch, W.C. 2006. Canopy temperature view angle affects on the water deficit index. ASABE Annual International Meeting. Portland Oregon, July 9- 12, 2006
- Bausch, W.C. 2006. Comparison of active and passive optical sensors for assessment of plant nitrogen. International Conference on Precision Agriculture Abstracts & Proceedings. Conference Abstract., pp 117; Minneapolis MN July 23-26, 2006.
- Wiles, L. 2006. Site-Specific Weed Management: Myth or Magic?. Meeting Abstract. NSF-ADVANCE Distinguished Lecture Series, Kansas State University, Dept. Agronomy 3/8/2006
- Heermann, D.F. 2006. Impact of variable well yield on center pivot packages. Proceedings of the Central Plains Irrigation Conference. p. 25- 34.
- Bausch, W.C., Delgado, J.A. 2005. Impact of residual soil nitrate on remote sensed plant n status of irrigated corn for managing in-season nitrogen applications. Precision Agriculture. Manuscript number PRAG276-04
- Bausch, W.C., Halvorson, A.D. 2006. Evaluation of active optical sensors for assessment of plant n in irrigated corn. Proceedings Great Plains Soil Fertility Conference. 11:149-154
- Mccutcheon, M.C., Farahani, H., Stednick,, J.D., Buchleiter, G.W., Green, T.R. 2006. Effect of soil water on apparent soil electrical conductivity and texture relationships in a dryland field. Biosystems Engineering.(2006) 94 (1), 19-32
- Shaner, D.L., Hornford, R. 2005. The science of basf's imidazolinone herbicides used in canada. Review Article. Volume 3:pp 23-30
- Shaner, D.L., Nadler-Hassar, T., Henry, W.B., Koger Iii, C.H. 2005. A rapid in vivo epsps assay with excised leaf discs. Weed Science. 53:769- 774
- Shaner, D.L., Westra, P., Nissen, S. 2006. Amads increases the efficacy of glyphosate formulations on corn. Weed Technology.Volume 20, PP179-183
- Ulbrich, A., Souza, J., Shaner, D.L. 2005. Persistence and carry over effect of imazapic and imazapyr in brazilian cropping systems. Weed Technology. 19:986-991
- Shaner, D.L., Brunk, G., Nissen, S., Westra, P. 2006. Soil dissipation and biological activity of metolachlor and s-metolachlor in five soils. Pest Management Science.DOI:1002/ps.1215
- Perez-Jones, A., Park, K.W., Colquhon, J., Mallory-Smith, C., Shaner, D.L. 2005. Identifcation of glyphosate-resistant italian ryegrass (lolium multiflorum) in oregon. Weed Science. 53:775-779
- Trout, T.J., Gartung, J.L. 2006. Use of crop canopy size to estimate crop coefficient for vegetable crops. Environmental and Water Resources Institute World Congress Proceedings. Omaha, NE May 21-25,2006
- Delgado, J.A., Bausch, W.C. 2006. Potential Use of Precision Conservation Techniques to Reduce Nitrate Leaching in Irrigated Crops. Journal of Soil and Water Conservation. 6-:379-387.
- Sadler, E.J., Bausch, W.C., Fausey, N.R., Ferguson, R.B. 2006. Improving water use efficiency in agriculture. In: Proceedings International Fertilizer Industry Association (IFA)/Chinese National Chemical Construction Corporation (CNCCC) Agriculture Conference, Optimizing Resource Use Efficiency for Sustainable Intensification of Agriculture. February 27-March 2, 2006, Kunming, China. 2006 CDROM.
- Delgado, J.A., Khosla, R., Bausch, W.C., Westfll, D., Inman, D. 2006. Nitrogen fertilizer management based on site-specific management zones reduce potential for NO3-n leaching. Journal of Soil and Water Conservation Society. 60:402-410
- Halvorson, A.D., Mosier, A.R., Reule, C.A., Bausch, W.C. 2005. Nitrogen and tillage affects on irrigated continuous corn yields. American Society of Agronomy Abstracts. CD-ROM Publication.
- Halvorson, A.D., Mosier, A.R., Reule, C.A., Bausch, W.C. 2006. Nitrogen and tillage effects on irrigated continuous corn yields. Agronomy Journal. 98:63-71.
- Henry, W.B., Calderon, F.J., Shaner, D.L. 2005. Fourier-transformed diffuse reflectance to measure herbicide injury in the nir and mid-ir in soybean and weed species. Agronomy Abstract. Presented at the 2005 ASA, CSSA-SSSA International Annual Meeting. Nov. 6-10, 2005. Salt Lake City, UT
- Henry, W.B., Koger III, C.H., Shaner, D.L. 2005. Accumulation of shikimate in corn and soybean exposed to various rates of glyphosate. Online. Crop Management doi:1094/CM-2005-1123-01-RS.
- Peters, R.T., Heermann, D.F., Stahl, K.M. 2005. The use of low-cost, differentially-corrected GPS for reporting field position of self- propelled irrigation systems. In: Irrigation Association Conference Proceedings, November 6-8, 2005, Phoenix, Arizona. 2005 CDROM.
- Trout, T.J., Buchleiter, G.W., Bausch, W.C. 2006. Research needs to sustain agriculture on the high plains with limited irrigation water supplies. Soil and Water Conservation Society Proceedings. Keystone Colorado 7/23/2006
- Trout, T.J. 2006. Estimating crop coefficients with crop canopy size. Acta Horticulture Proceedings. Mildura, Australia. August, 2006.
- Trout, T.J. 2006. Fumigant Use Trends In California - Response To The MeBr Phaseout. American Chemical Society Abstracts. San Fransico, CA 9/10/2006
- Farahani, H.J., Shaner, D.L., Buchleiter, G.W., Bartlett, G.A. 2006. Evaluation of a low volume agro-chemical application system for center pivot irrigation. Applied Engineering in Agriculture. Volume 22(4): 517- 528
- Rainbolt, C., Thill, D., Zemetra, R., Shaner, D.L. 2005. Imidazolinone- resistant wheat acetolactate synthase in vivo response to imazamox. Weed Technology. 19:539-549
- Trout, T.J., Gartung, J.L. 2005. Energy use in micro-irrigation. Irrigation Assocation Exposition and Technical Conference Proceedings. Proc. Nov 6-8, pp 62-76.
- Trout, T.J., Skaggs, T.H., Rothfuss, Y. 2005. Irrigation practices that improve drip fumigation.. Methyl Bromide Alternatives and Emissions Research Conference Proceedings. Annual International Research Conference on Methyl Bromide Alternatives And Emissions Reductions Conference 2005, pp 35-1 - 35-3.
- Ajwa, H.A., Trout, T.J. 2006. Polyacrylamide and water quality effects on infiltration in sandy loam soils. Soil Science Society of America Journal, Vol. 70:643-650.
- Wyse Pester, D.Y., Wiles, L., Westra, P. 2002. The potential for mapping nematode distributions for site-specific management. Journal of Nematology. 34(2):80-87
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Progress 10/01/04 to 09/30/05
Outputs
1. What major problem or issue is being resolved and how are you resolving it (summarize project aims and objectives)? How serious is the problem? What does it matter? The major problem being addressed is how to minimize adverse environmental impacts from crop production systems while producing a reliable and safe food supply. Agricultural crop production has been identified as a major nonpoint source of water quality degradation because of contamination from pesticides and nitrates in groundwater resulting from excessive application of water, pesticides, and fertilizers. The National priority to provide an adequate supply of safe drinking water requires efforts to reduce quality degradation by various major water users. Increasing competition for land and water resources and increasing pressure to curtail or more closely regulate agricultural operations because of environmental concerns are forcing producers to consider alternative crop production systems to
continue in operation. Irrigation is a critical component of American agriculture since about 40% of the nation's total crop value is produced on the 15% of the cropland that is irrigated. Precision agriculture is a management strategy that uses information technologies to bring data from multiple sources to bear on decisions associated with crop production. We are addressing the development of integrated systems that can analyze these data to recommend scientifically based management strategies and deliver site specific applications of water, fertilizers, and pesticides. Field sampling strategies, models and remote sensing technology for applying the right amount of water and fertilizer are being developed and evaluated. We are adapting sprinkler irrigation systems to apply chemicals such as fertilizers and pesticides when and where needed during the growing season. A multidisciplinary approach is necessary to get a better understanding of how various nutrient, water, pest, and
climatic factors affect yield variability. Our goal is to increase the scientific understanding of many of the interactions within the crop production system, so the appropriate data are analyzed correctly to make improved management decisions. Our approach is to study commercial fields rather intensively over a 5+ year period. Comparison of different scenarios will provide the basis for assessing the environmental impact and economic feasibility of PF. We are working with industry partners through CRADAs to develop and evaluate economical alternative data collection procedures to characterize soil and crop status as well as variable rate application technologies for water, fertilizers, and pesticides that are economically feasible for producers to use. If producers are to benefit from adopting PF, they must make significant capital investments in equipment and data collection activities as well as obtain the analytical expertise to translate the voluminous data into improved
management decisions. Generally, the science of interpreting and integrating the various kinds of PF data is not well understood and the environmental benefits that have been promised have not been well documented. Producers are not certain whether this new technology is technically or economically practical. Although preliminary PF research indicates herbicide use may be reduced 30 60% without affecting crop yield or quality, the economic feasibility should be carefully evaluated before producers make large capital investments for this and other PF management strategies. Water quality degradation and increase in water demand requires new knowledge and improved systems for using our water resources more efficiently to sustain production of high quality food and fiber. 2. List the milestones (indicators of progress) from your Project Plan. Objective 1 Milestones - Assess Spatial & Temporal Variability: 1a1. Collect and interpret soil electrical conductivity data. Completed
evaluations will be used to train 5 customers to use the protocols and evaluations of customers maps will be completed. 1a2. Collect multispectral imagery of several fields and analyze to assess in-season variability. Develop/modify and field test protocols for collection of remote sensing data. Test protocols on several cooperators fields. 1b1. Assess variability of water and nitrogen application. Evaluate accuracy and usability of simulation processes versus baseline collected data. Develop simplified protocols for customers to allow field scale assessments for improved management. 1b2. Characterize spatial distribution of weed populations through the collection of weed and seed bank data. Analyze collected data to describe spatial and temporal dynamics of weed populations. 1c1. Develop cost effective methods to sample and make maps for site- specific weed management. Various methods and sampling strategies will be investigated. 1d1. Develop tools using various statistical
techniques and data mining procedures to identify factors affecting yield variability. Classification and regression trees, neural networks and other analysis techniques will be explored with the objective of providing users recommendations for analysis protocols and provide feedback to data collection strategies. 1e1. Develop a weed population dynamics model. Initiate model development, identify data gaps, parameterize and verify the model. Perform simulation experiments and conduct field evaluations. Objective 2 Milestones - Assess Potential Benefits of Precision Application: 2a1. Analyze water and nitrogen conservation potential with Precision Farming. Select appropriate simulation models to evaluate management impacts on the environment. Use model to evaluate multi-year impacts on several fields using calibrated model. Expand beyond nitrogen and water if success is achieved. 2a2. Refine sprinkler evaluation software to meet NRCS and industry needs. Model to be enhanced for
new applicators and for entire field evaluation. Test model with NRCS and industry. Consider updating standards for center pivot and linear move evaluations. 2b1. Improve site specific management for water and nitrogen to manage limited water quantity and enhance water quality with economic benefits. Plot studies in commercial fields will be studied to evaluate management strategies and evaluate the economic impact of improved water and nitrogen management. 2c1. Assess potential to reduce herbicide use with site specific weed management model. Utilize an educational model and test with growers. Complete and test scientific model and stochastic simulation method. Objective 3 Milestones - Develop and Evaluate Strategies for Precision Farming Management: 3a1. Use remote sensing to optimize irrigation/nitrogen management. Collect data and optimization technique with farmer practices. Field test on customer managed fields with a couple of crops. 3b1/2. Develop irrigation/nitrogen
scheduling prototype software. Establish criteria, develop and test prototype model. Upgrade model to include Nitrogen reflectance index. 3b3. Explore with industry the addition of improved water management software as an integral part of irrigation system controls. 3c1. Develop decision support tool for site specific weed management in corn. Design, test and obtain user evaluation. Objective 4 Milestones - Improve Uniform Technology and use both Conventional and Irrigation System to deliver water and chemicals variably: 4a1. Test through simulation, laboratory and field tests the uniformity of a commercial chemical application (accupulse) system. 4b1. Modify in conjunction with industry the accupulse system for variable application of chemicals with a center pivot irrigation system. 4c1. Develop site specific weed management model to create variable application maps that can apply with accupulse system. 4d1. Evaluate variable N application maps generated from
remotely sensed data and field test for improved management. 3a List the milestones that were scheduled to be addressed in FY 2005. For each milestone, indicate the status: fully met, substantially met, or not met. If not met, why. 1. Evaluate use of EC maps to infer the spatial variability of texture, soil water properties, and pesticide binding and leaching potentials. Work with the cooperator (new in 2004) to assess potential for using EC and yield maps collected in 2004 to change weed, water, and nutrient management. Identify and map EC of fields with much different soil types to further assess potential for improving water and herbicide management. Milestone Substantially Met 2. Use active optical sensor and spectroradiometer to monitor canopy and plant N status of corn and potatoes. Evaluate mounting options of the active sensor on a center pivot sprinkler system. Finish analysis of satellite data to compare with corn canopy N status. Milestone Substantially Met 3.
Analyze multi-site, multi-year EC, yield, and plant biomass and canopy N status estimates from remotely sensed data to determine if in-season and end-of-season plant parameters correlate with soil property estimates from EC measurements. Milestone Substantially Met 4. Evaluate the potential value of using a detailed soil-water-crop computerized model (RZWQM) to simulate water, nitrogen, and herbicide movement in irrigated sandy soils. Initial efforts will concentrate on compiling the past six years of field data from Wiggins and Yuma, constructing model input data files, and calibrating RZWQM for the prevailing management and cropping systems. Milestone Not Met Critical SY Vacancy 5. Evaluate weed management zones based on soil mapping and weed distribution in fields. Milestone Substantially Met 6. Develop maps on distribution of glyphosate-resistant weed populations in Colorado. Milestone Not Met Progress slowed by resource limitation (human,fiscal,equipment, etc. 7. Determine
relationship(s) between soil texture and EC that are useful in predicting herbicide behavior. Milestone Substantially Met 8. Determine the relationship between frequency of herbicide use and degradation of the herbicide in irrigated corn. Milestone Substantially Met 9. Evaluate the utility of active sensors on field equipment for identifying presence/absence of weeds and spraying as needed. Milestone Substantially Met 10. Test RZWQM predictions on herbicide behavior in field with data collected on herbicide movement and dissipation from two different fields. Milestone Not Met Critical SY Vacancy 11. Enhance CPED for new applicators and for entire field evaluation. Do more comprehensive testing of the existing model with NRCS and industry. Milestone Substantially Met 12. Quantify herbicide efficacy dissipation and leaching potential under field conditions, coupled with detail laboratory soil column studies to evaluate herbicide behavior under varying management. Milestone
Substantially Met 13. Upgrade the prototype irrigation and nitrogen scheduling program to include a nitrogen budget component and structured modularly in an object oriented language. Milestone Not Met Critical SY Vacancy 14. Explore with industry the addition of improved water management software as an integral part of irrigation system controls including adding improved water measurement devices. Milestone Substantially Met 15. Continue evaluating the value/benefits of variable application using a specially modified high-clearance tractor applicator capable of applying chemicals and/or liquid fertilizer like a center pivot as well as a conventional ground applicator. Substantially met Milestone Substantially Met 3b List the milestones that you expect to address over the next 3 years (FY 2006, 2007, and 2008). What do you expect to accomplish, year by year, over the next 3 years under each milestone? FY 2006 Milestone 1a2 - Evaluate robustness and reliability of an active optical
sensing system for acquiring plant N status to manage in-season N applications on irrigated corn. Evaluate various sensor mounting options. Milestone 1a2, 1d1. Analyze multisite, multiyear EC, yield and in-season plant parameters estimated from canopy reflectance measurements to determine if in-season plant parameters correlate with soil property estimates from EC measurements. Milestone 1c1. Develop easy to use software to automatically estimate and map % green cover in digital images collected in fallow fields. The method to collect digital images has already been developed with images collected when traveling 4 to 5 mph. Milestone 2a2: Begin updating standards for center pivot and linear move evaluations Milestone 2b1. Investigate use of infrared thermometers mounted on a center-pivot sprinkler to detect plant water stress and its spatial extent in a commercial irrigated corn field. Evaluate various techniques requiring canopy temperature for potential management of limited
water supplies. Milestone 2c1. a. WeedSite is a model that was developed for growers to estimate the benefits of postemergence site-specific weed management compared to uniform in irrigated corn fields. This model will be expanded for comparison of site-specific and uniform management of soil-applied herbicides. b. Assess potential to reduce postemergence herbicide use with site- specific weed compared to uniform management. Extensive data has already been collected for this analysis. c. Evaluate effectiveness of variable rate herbicide application based on EC zones in farmers' fields. d. Determine impact of variable rate herbicide application on ground and surface water contamination based on models and field measurements. Milestone 4b1. a. Continue design/modifications to high-clearance tractor for variable rate application of chemicals and field test for application uniformity. b. Use the modified high clearance tractor on field plot studies, to compare the performance and
efficacy of various application methods for nitrogen and pesticides. By strategically locating the various plots according to our variable rate criteria, the performance and value of variable rate application will be evaluated for the different application methods. FY 2007 A new CRIS will be written in 2006 and implemented in 2007. 4a What was the single most significant accomplishment this past year? Herbicide use may be reduced with site-specific weed control compared to uniform management, but reductions vary with the spatial distribution of weeds and the method of site-specific management. Growers, and agricultural consultants can use the software WeedSite to investigate variability in their irrigated corn fields based on hand drawn maps. Databases of herbicides have been updated for relevance to current management. WeedSite can be downloaded for free from an ARS website. The program can also be obtained on a CD. 4b List other significant accomplishments, if any. The amount of
glyphosate used has dramatically increased in recent years and has resulted in the selection of resistance in weeds. A leaf disc assay was developed that can be used to determine if a weed is resistant to glyphosate. This assay is rapid and relatively simple and will be useful for screening weed populations that are not controlled by glyphosate so that farmers can change their weed management program in a timely fashion. Nitrogen (N) fertilizer has received attention for a long time as a potential source of ground water pollution because of the mobility of the nitrate ion through the soil and because of the large amount of N fertilizer used. Significant savings in applied N have been reported by monitoring the crops N status during the growing season and applying N as needed by the crop and where needed in the field. These studies used passive type sensors that require the presence of sunlight. Active sensors provide their own illumination which means they can be used to take
measurements anytime of day under all possible sky conditions. Studies are being conducted by the Water Management Research Unit to evaluate these sensors. The potential impact of this type of sensor is that they could be mounted on a center-pivot or linear-move sprinkler system to provide real-time data to an on-board computer so that the sprinkler system could be used as the vehicle to apply N when and where needed by the crop. 4d Progress report. The project suffered a major setback with the resignation of a CAT 1 scientist: Uniformity of chemical application by Accu-Pulse Bromide, a water soluble dye and herbicides were applied through a 7 tower Accu-pulse system. Data collection for the AccuPulse test in the lab was completed and data are being analyzed so the evaluation of performance can be completed. The AccuPulse system applied all three markers very uniformly across the 7 tower system. Development of a variable rate application system: Modifications to a high-clearance
tractor were completed for use with a 40-ft spray boom and an eight-row coulter fertilizer applicator for in- season N application to irrigated corn. Preliminary testing was conducted with the coulter fertilizer toolbar to find that the tractor did not have sufficient power. An engine replacement is currently underway. Testing of active optical sensors: Two commercially available active optical sensors were compared to a research grade passive mutispectral radiometer to monitor plant nitrogen (N) status of irrigated corn in a commercial center-pivot irrigated field and in plots with various imposed N treatments. Two mounting options for one of the active sensors were investigated (nadir and oblique views). Sensor mounting on a center pivot sprinkler system will not be attempted until the sensors operational characteristics with a developing crop canopy are fully understood. Additional processing of Quick Bird satellite images from 2003 did not happen because the person with image
analysis expertise is no longer with the research unit. Mapping differences in herbicide behavior across a field: Soil was collected from high and low EC regions from 3 different fields in eastern Colorado where atrazine, metolachlor, or pendimethalin had been applied. It was found that atrazine disappeared very quickly in all of these fields that had been under continuous corn for at least 3 years. Laboratory studies showed that there is enhanced metabolism of atrazine in soils that had received multiple applications of the herbicide for several years. This phenomenon is being studied further. Utilization of EC to map soil heterogeneity in the field: EC maps from a producer were used to recommend a small set of soil sampling sites. Soil texture and nutrient data obtained from these sites were combined with EC data to develop improved water holding capacity maps that the producer used for water and nutrient management. EC data for two fields at ARDEC with silty clay soil were
mapped and sampled to quantify differences in water holding capacities. Image Analysis to Map Weeds in Fallow Fields: Growers may be able to control weeds with less herbicide with site- specific weed management (SSWM), but many growers need inexpensive, simple and convenient methods for making georeferenced weed maps because sprayers that detect weeds and automatically apply herbicide are expensive. Further, historic information on how weeds are distributed within a field can be valuable for prescribing SSWM. We designed a system to collect digital images in fallow fields with a commercially available digital camera. Then we developed an algorithm to estimate % green cover in the digital images. In preliminary tests, accuracy of estimating % green cover in an image was 90 to 98%. 5. Describe the major accomplishments over the life of the project, including their predicted or actual impact. The selection of herbicide resistant weed populations is increasing and there is a need to
develop simple methods to determine if a weed population is resistant to certain herbicides so that an effective weed management program can be implemented. We have developed relatively simple leaf disc assays for determining resistance to ALS inhibitors, photosynthesis inhibitors and glyphosate. These assays have been used successfully in the field to detect resistance in different weed populations. Whole-field EC data from three commercial center pivot fields in Colorado were collected for 1998-2003 and analyzed using GIS and statistical packages. These analyses found strong relationships between yield and soil electrical conductivity (EC), but the relationships between EC and various soil productivity factors, were needed to be useful for site-specific management. The implementation of variable rate herbicide application depends on finding a means to economically map soil variability in the field. Three significant results applicable to non- saline agricultural fields were
found: 1) soil electrical conductivity maps are highly stable over time and do not require annual mapping, 2) soil electrical conductivity correlates strongly with texture (clay content), organic matter and soil water, and 3) the fields could be divided into herbicide binding zones based on soil EC, and subsequent sampling of areas of these fields that had not been previously sampled showed that we could predict herbicide binding with good accuracy. Field EC mapping provides a sound method of subdividing the field into yield response and soil management zones for the purpose of implementing variable-rate application of nutrients and pesticides to reduce input costs and enhance the environment. Spatial and temporal variability of soil N supply in conjunction with temporal variability of plant N demand makes conventional N management difficult for site specific N applications. Soils in historically high and low yielding areas within a commercial center-pivot irrigated corn field in
northeastern Colorado were sampled to determine NO3-N levels before and after the growing season to evaluate effectiveness of in- season N management based on remotely sensed crop N assessment. Crop N status was assessed at least weekly during vegetative growth to determine when to apply N. Applications of N based on remote sensing were 180 lb/ac less than the adjacent producer practice in the high yield area and 109 lb/ac less in the low yield area. These significant reductions in N application amounted to $50.40/ac in the high yield area and $30.50/ac in the low yield area at 2001 prices for N fertilizer. Residual NO3-N in the crop root zone was reduced by 117 lb/ac in the high yielding area and remained at similar levels for the low yielding area. In-season N application was reduced based on crop "need" while not reducing grain yield, and crop root zone soil NO3-N levels were reduced which minimizes potential N leaching and degradation of the environment. The efficient
application of chemicals is a challenge for farmers to maintain an economical production system while being good environmental stewards. Field studies with water sensitive paper have shown the coverage uniformity of AccuPulseTM to be comparable to conventional ground application and superior to aerial application. In many high value crops, fungicides that leave a chemical residue on leaves for disease protection, are applied multiple times either by air or chemigation. For chlorothalonil, a widely used fungicide on potatoes, foliage treated with AccuPulse had shown a 10 fold increase in residue compared to chemigation. Futhermore, the concentration of fungicide remaining on the leaves 7 days after application was greater on plants treated with AccuPulse, than on leaves 1 day after treatment with chemigation. These results suggest that farmers can significantly reduce the number of applications of fungicides by utilizing AccuPulse while still maintaining efficacy for controlling
diseases. Replicated plot studies were done within the cooperating farmer's field for 2 years, to determine whether yields in historically low yielding areas could be substantially increased by more intensive water and nitrogen management that minimized any water or nitrogen stress to the crop. Historical yield data were used to identify low (>=15% below mean), average, and high (>=15% above mean) productivity areas. In the first year, there was a 15% increase in corn yield in the low productivity area when supplemental water and nitrogen were applied to insure there was no water or nitrogen stress. In the second year, there was a 10% increase in potato yields in the low production area when 15% additional water was applied to relieve water stress between farmer-managed irrigations. Potato yields were not decreased when the farmer practice of applying 90 lbs/ac of preplant nitrogen was omitted for a savings of $20.00 /ac in reduced fertilizer costs. These results indicate water is
a significant factor affecting yield, but the additional cost of improved management and application technology probably limits the economic feasibility of adoption. Site-specific weed management is a technique for controlling weeds in crops with less herbicide by mapping the weed population in a field and then treating only the areas of a field where control is economically justified and varying management for the most efficient control when the species present varies within a field. However, growers cannot adopt this strategy until 1) they are confident that the benefits of site-specific weed management will exceed the costs, and 2) they have cost effective methods to make weed maps. Our research addresses both these obstacles so site-specific weed management can become a cost-effective method for growers to control weeds with less herbicide. 1) The benefits of site- specific weed management vary with both the distribution of weeds in a field and the site-specific strategy used.
We have developed software for growers to investigate the potential benefits of postemergence site- specific weed management in their irrigated corn fields. The software predicts the outcome of uniform and 4 different site-specific management strategies based on hand drawn weed maps. 2) In cooperation with a private company, we designed and are testing a low cost package (< $4000) of commercially available software and hardware for making weed maps. Our design is a digital camera mounted on a tractor or ATV with automated analysis of digital images to create a map of weed cover within a field. Growers and agricultural consultants need models to predict changes in the number, species and distribution of weeds in cropped fields in response to management so they can anticipate and mitigate weed problems that may be created by using new weed management technologies. WISDEM is model developed by the ARS for this purpose. Scientists of the ARS Water Management Research Unit, Colorado
State University and a private crop protection company, are modifying WISDEM to predict potential weed problems from use of herbicide resistant crops. They have developed expert opinion that can be used in lieu of missing and costly data on weed biology required by the model and are improving the model's interface for use by growers and agricultural consultants. With these changes, WISDEM can become a means to help safeguard and improve critical tools for cost-effective and environmentally sound weed management. 6. What science and/or technologies have been transferred and to whom? When is the science and/or technology likely to become available to the end- user (industry, farmer, other scientists)? What are the constraints, if known, to the adoption and durability of the technology products? Participated in 5 workshops with major agrochemical companies, and growers on herbicide-soil interactions and how these interactions affect herbicide activity and dissipation. Participated in a
workshops with a major agrochemical company on herbicide resistance and the utilization of leaf disc assays to measure resistance to ALS inhibitors and glyphosate. Participated in a special session at the 2004 Aquatic Plant Management Society on herbicide resistance management in aquatic systems. Information on in-season N management using ground-based and satellite remote sensing was presented to interested parties at a field day organized at the Yuma research site. Techniques for estimating plant N status from remotely sensed canopy reflectance have been transferred to the scientific community through presentations. Industry, consultants, and farmers can make use of this technology to determine when nitrogen applications should be made through use of commercial satellite data. Two commercially available active optical sensors were compared to a research grade passive mutispectral radiometer to monitor plant nitrogen (N) status of irrigated corn in a commercial center-pivot
irrigated field and in plots with various imposed N treatments. Two mounting options for one of the active sensors were investigated (nadir and oblique views). The ability to actively monitor the N status of plants from the center pivot will make variable rate nitrogen application more feasible. The Center Pivot Evaluation and Design program has been distributed to NRCS, industry and other interested users via the internet for their use in evaluating uniformities of center pivot sprinkler systems. Presented training sessions on CPED for the NRCS at North Platte,NE and at the Central Plains Irrigation Association at Kearney, NE. Presented overview of Precision Farming at Workshops held at Lamar and Brush, Colorado. These workshops were attended by producers and action agency personnel. Provided soil EC maps and technical advice to the University of Wyoming for developing a new Ag Experiment Station farm. Presented research results on relating soil electrical conductivity data with
soil water properties that could improve irrigation management at Extension Service sponsored field days in eastern Colorado. Equipment for measuring soil electrical conductivity is commercially available. There is interest from some of the 'progressive' producers to map fields to aid in identifying and rectifying production problems related to the soil. Sound advice on interpreting EC is limited but should improve in the next 5 years as consultants and other ag service providers gain more experience. AccuPulse, an independent, low-volume chemical application system, mounted on a center pivot irrigation system, has been available to producers for several years. However, the manufacturer has stopped production and marketing of this system because of difficulties in providing technical support through their dealers and sluggish sales in the ag sector. The technology still appears to be viable technically but additional research and technical support are needed to help producers
improve their level of management to fully utilize this technology. Herbicide use may be reduced with site-specific weed compared to uniform management, but reductions vary with the spatial distribution of weeds and the method of site-specific management. Growers, agricultural consults can use the software WeedSite to investigate variability in their irrigated corn fields based on hand drawn maps. Databases of herbicides have been updated for relevance to current management. WeedSite can be downloaded for free from an ARS website. The program can also be obtained on a CD. Growers may be able to control weeds with less herbicide with site- specific weed management (SSWM), but many growers need inexpensive, simple and convenient methods for making georeferenced weed maps because sprayers that detect weeds and automatically apply herbicide are expensive. Further, historic information on how weeds are distributed within a field can be valuable for prescribing SSWM. We designed a
system to collect digital images in fallow fields with a commercially available digital camera. Then we developed an algorithm to estimate % green cover in the digital images. In preliminary tests, accuracy of estimating % green cover in an image was 90 to 98%. 7. List your most important publications in the popular press and presentations to organizations and articles written about your work. (NOTE: List your peer reviewed publications below). Wiles, L. J. 2005 Users Manual for WeedSite. 7 pp Bausch, W.C. 2005. Evaluation of vegetation indices to estimate fraction vegetation cover for the Water Deficit Index. Oral Presentation. ASAE Annual International Meeting, July 17-20, 2005. Tampa, FL. (No ARS-115) Bausch, W.C. and M.K. Brodahl. 2004. In-season nitrogen management for irrigated corn: Effects on grain yield. In Annual Meeting Abstracts CD- ROM. ASA, CSSA, SSSA, Oct. 31- Nov. 4, 2004. Seattle, WA. Shaner, D. L., and R. Hornford. 2005. Soil Interactions of Imidazolinone
Herbicides Used in Canada. Oral presentation. CWSS annual meeting, Winnipeg, Manitoba, Canada. November 28-30, 2004. Shaner, D. L., T. Nadler-Hassar, B. Henry, and C. Koger. A rapid in vivo EPSPS assay with excised leaf discs of crops and weeds. WSSA Annual Meeting. Honolulu, HI. February 7-10, 2005. Core, J. 2005 New tests screen for glyphosate resistance. USDA press release. June 21, 2005.
Impacts
(N/A)
Publications
- Koger III, C.H., Shaner, D.L., Henry, W.B., Nadler-Hassar, T. 2005. Assessment of two non-destructive assays for detecting glyphosate resistance in conyza canadensis. Weed Science. 53(4):438-445.
- Westra, P., Shaner, D.L., Nissen, S., Haley, S., Johnson, J., Helm, A., Henry, W.B. 2004. Weed control for colorado farmers and wheat producers. Popular Publication. p. 58-67.
- Tan, S., Evans, R., Dahmer, M., Singh, B., Shaner, D.L. 2005. Imidazolinone-tolerant crops: history, current status, and future. Pest Management Science. Volume 61:pp246-257
- Wiles, L. 2005. Sampling to make maps for site-specific weed management. Weed Science. 53:228-235
- Wiles, L. 2004. Economics of weed management: principles and practices. Weed Science. Weed Technology 18:1403-1407.
- Fleming, K.L., Heermann, D.F., Westfall, D.G. 2004. Evaluating soil color with farmer input and apparent soil electrical conductivity for management zone delineation. Agronomy Journal. Vol. 96, Issue 6, Manuscript A03-0307. Nov.-Dec., 2004.
- Luz, P.B., Heermann, D.F. 2005. A statistical approach to estimating runoff in center pivot irrigation with crust conditions. Agricultural Water Management. Vol 72 (1) pp 33-46
- Bausch, W.C., Diker, K., Khosla, R., Paris, J.F. 2004. Estimating corn nitrogen status using ground-based and satellite multispectral data. Proceedings of SPIE.
- Farahani, H., Buchleiter, G.W., Brodahl, M.K. 2004. Characterization of apparent soil electrical conductivity variability in irrigated sandy and non-saline fields in colorado. Transactions of the ASAE.
- Diker, K., Heermann, D.F., Brodahl, M.K. 2004. Frequency analysis of yield for delineating yield response zones. Precision Agriculture.
- Luz, P.B., Heermann, D.F. 2005. A statistical approach to estimating runoff in center pivot irrigation with crust conditions. Agricultural Water Management.
- Schleicher, T.D., Bausch, W.C., Delgado, J.A. 2003. Low ground cover filtering to improve reliability of nri corn n status classification. Transactions of the ASAE.
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Progress 10/01/03 to 09/30/04
Outputs
1. What major problem or issue is being resolved and how are you resolving it (summarize project aims and objectives)? How serious is the problem? What does it matter? The major problem being addressed is how to minimize adverse environmental impacts from crop production systems while producing a reliable and safe food supply. Agricultural crop production has been identified as a major nonpoint source of water quality degradation because of contamination from pesticides and nitrates in groundwater resulting from excessive application of water, pesticides, and fertilizers. The National priority to provide an adequate supply of safe drinking water requires efforts to reduce quality degradation by various major water users. Increasing competition for land and water resources and increasing pressure to curtail or more closely regulate agricultural operations because of environmental concerns are forcing producers to consider alternative crop production systems to
continue in operation. Irrigation is a critical component of American agriculture since about 40% of the nation's total crop value is produced on the 15% of the cropland that is irrigated. Precision agriculture is a management strategy that uses information technologies to bring data from multiple sources to bear on decisions associated with crop production. We are addressing the development of integrated systems that can analyze these data to recommend scientifically based management strategies and deliver site specific applications of water, fertilizers, and pesticides. Field sampling strategies, models and remote sensing technology for applying the right amount of water and fertilizer are being developed and evaluated. We are adapting sprinkler irrigation systems to apply chemicals such as fertilizers and pesticides when and where needed during the growing season. A multidisciplinary approach is necessary to get a better understanding of how various nutrient, water, pest, and
climatic factors affect yield variability. Our goal is to increase the scientific understanding of many of the interactions within the crop production system, so the appropriate data are analyzed correctly to make improved management decisions. Our approach is to study two commercial fields rather intensively over a 5+ year period. Comparison of these two scenarios will provide the basis for assessing the environmental impact and economic feasibility of PF. We are working with industry partners through CRADAs to develop and evaluate economical alternative data collection procedures to characterize soil and crop status as well as variable rate application technologies for water, fertilizers, and pesticides that are economically feasible for producers to use. If producers are to benefit from adopting PF, they must make significant capital investments in equipment and data collection activities as well as obtain the analytical expertise to translate the voluminous data into improved
management decisions. Generally, the science of interpreting and integrating the various kinds of PF data is not well understood and the environmental benefits that have been promised have not been well documented. Producers are not certain whether this new technology is technically or economically practical. Although preliminary PF research indicates herbicide use may be reduced 30 60% without affecting crop yield or quality, the economic feasibility should be carefully evaluated before producers make large capital investments for this and other PF management strategies. Water quality degradation and increase in water demand requires new knowledge and improved systems for using our water resources more efficiently to sustain production of high quality food and fiber. 2. List the milestones (indicators of progress) from your Project Plan. Objective 1 Milestones - Assess Spatial & Temporal Variability: 1a1. Collect and interpret soil electrical conductivity data. Completed
evaluations will be used to train 5 customers to use the protocols and evaluations of customers maps will be completed. 1a2. Collect multispectral imagery of several fields and analyze to assess in-season variability. Develop/modify and field test protocols for collection of remote sensing data. Test protocols on several cooperators fields. 1b1. Assess variabilities of water and nitrogen application. Evaluate accuracy and usability of simulation processes versus baseline collected data. Develop simplified protocols for customers to allow field scale assessments for improved management. 1b2. Characterize spatial distribution of weed populations through the collection of weed and seed bank data. Analyze collected data to describe spatial and temporal dynamics of weed populations. 1c1. Develop cost effective methods to sample and make maps for site- specific weed management. Various methods and sampling strategies will investigated 1d1. Develop tools using various
statistical techniques and data mining procedures to identify factors affecting yield variability. Classification and regression trees, neural networks and other analysis techniques will be explored with the objective of providing users recommendations for analysis protocols and provide feedback to data collection strategies. 1e1. Develop a weed population dynamics model. Initiate model development, identify data gaps, parameterize and verify the model. Perform simulation experiments and conduct field evaluations. Objective 2 Milestones - Assess Potential Benefits of Precision Application: 2a1. Analyze water and nitrogen conservation potential with Precision Farming. Select appropriate simulation models to evaluate management impacts on the environment. Use model to evaluate multi-year impacts on several fields using calibrated model. Expand beyond nitrogen and water if success is achieved. 2a2. Refine sprinkler evaluation software to meet NRCS and industry needs. Model to be
enhanced for new applicators and for entire field evaluation. Test model with NRCS and industry. Consider updating standards for center pivot and linear move evaluations. 2b1. Improve site specific management for water and nitrogen to manage limited water quantity and enhance water quality with economic benefits. Plot studies in commercial fields will be studied to evaluate management strategies and evaluate the economic impact of improved water and nitrogen management. 2c1. Assess potential to reduce herbicide use with site specific weed management model. Utilize an educational model and test with growers. Complete and test scientific model and stochastic simulation method. Objective 3 Milestones - Develop and Evaluate Strategies for Precision Farming Management: 3a1. Use remote sensing to optimize irrigation/nitrogen management. Collect data and optimization technique with farmer practices. Field test on customer managed fields with a couple of crops. 3b1/2. Develop
irrigation/nitrogen scheduling prototype software. Establish criteria, develop and test prototype model. Upgrade model to include Nitrogen reflectance index. 3b3. Explore with industry the addition of improved water management software as an integral part of irrigation system controls. 3c1. Develop decision support tool for site specific weed management in corn. Design, test and obtain user evaluation. Objective 4 Milestones - Improve Uniform Technology and use both Conventional and Irrigation System to deliver water and chemicals variably: 4a1. Test through simulation, laboratory and field tests the uniformity of a commercial chemical application (accupulse) system. 4b1. Modify in conjunction with industry the accupulse system for variable application of chemicals with a center pivot irrigation system. 4c1. Develop site specific weed management model to create variable application maps that can applied with accupulse system. 4d1. Evaluate variable N application maps generated
from remotely sensed data and field test for improved management. 3. Milestones: A. 1c1 & 2c1 - Determination of feasibility of weed management zones utilizing variable rate application of soil applied herbicides based on soil EC. Measure the effects on efficacy dissipation and leaching potential under field conditions. Development of field assays for measuring resistance to herbicides other than ALS inhibitors and surveys of weed populations in the field. Testing of current models' prediction of herbicide behavior under laboratory and field conditions. The variability of leaching and dissipation of atrazine and acetochlor applied to different EC zones was determined at 10 different sites (5 in low EC and 5 in high EC zones) within a field. Results showed slightly more leaching in the low EC zones versus the high EC zones, which correlated with the binding of the herbicides to the soil, but more than 80% of the herbicides stayed in the top 10 cm of the soil surface in both zones.
Both herbicides dissipated extremely rapidly (half life of 6 days) in both EC zones and laboratory results confirmed that this dissipation was due to microbial activity, which may be related to the history of use of these herbicide in this field. Intact soil columns have been taken from two EC zones and will be used to test model predictions of herbicide behavior in the different zones. A leaf disc assay was developed that can determine resistance to glyphosate and has been tested on conventional and glyphosate resistant crops and on glyphosate resistant weed populations in the greenhouse and field. 4b1 - Begin any software development required to implement variable rate application with the AccuPulse system. Determine the methods for increasing the coverage of spray droplets applied via AccuPulse such as adjuvants, spreader design, etc, without compromising anti-drift potential of system. The processing of variable rate maps to input to the accupulse system for variable rate
control was completed. Algorithms were developed to provide the angle for controlling the application of chemicals from tower to tower on a center pivot sprinkler system. This considered the time to reach the new steady state application rate. The maps for test cases included maps for variable rate herbicide and fertilizer applications. A test on the distribution of herbicides applied through AccuPulse under windy conditions showed very even distribution under these adverse conditions. The effect of adjuvants on the distribution of spray droplets from AccuPulse was measured utilizing a fluorescent dye and showed much better leaf coverage when an adjuvant was included in the spray solution. 2c1 - Distribution of computer software that growers, agricultural consultants and other decision makers can use to evaluate how much herbicide use may be reduced with site-specific weed management in their irrigated corn fields and the impact on crop yield and weeds left in the field that will
produce seed. Distribution was delayed by an unanticipated problem with the commercial GIS development code needed to complete the software. The software (WeedSite)will be available for free on an ARS website as soon as herbicide databases are updated (September or October 2004). 1c1 - Determine the position of the camera for most accurate mapping of weed populations with an inexpensive system using a video camera mounted on a tractor. Also, assess whether video mapping of weeds is accurate enough for making management decisions. Video images did not have sufficient resolution for weed mapping so we developed a system with digital camera mounted on an ATV for collecting true color, still images while traveling at 3-6 mph. Also, image analysis algorithms were developed to assess weed cover in images collected in fallow fields. 1a1 - Work with several cooperators to field test the best analytical techniques for interpreting EC data and relating it to soil parameters affecting the
water holding capacity Two additional cooperators' fields were mapped. Field EC mapping was demonstrated to provide a sound method of subdividing the field into soil management zones. The ongoing interdisciplinary precision farming research of WMU and cooperating scientists at Colorado State University has adapted the EC method to sub divide large fields as the basis for variable rate application and have shown the method to have economic advantages. Because of the simplicity of EC mapping to identify field variability, cooperating farmers have adopted the method and are encouraging the furthering of its utility. 1b1, 2b1, 3b1/2 - Complete testing of an integrated irrigation and nitrogen budgeting prototype program that contains appropriate science as well as capabilities for updating water and nitrogen amounts based on real-time feedback. A prototype of the irrigation scheduling program with the recently standardized method (adopted by Amer. Soc. of Civil Eng.) for calculating
reference ET and an improved user interface for easier updating, was written in Microsoft Access and tested. Plans are to port this to a modular object oriented platform (VBNet) and incorporate the nitrogen budgeting aspect with the water budget. 4a1 - Complete evaluation of the application performance of a complete 7 tower AccuPulse system primarily in the laboratory. Initiate software development required to implement variable rate application with the AccuPulse system. The application uniformity of the 7 tower AccuPulse system measured in the lab but based on operating times measured in the field, was approximately 90% (Christiansen CU) although the performance of several nozzles was erratic. The evaluation of the applied chemical uniformity is in progress and will be completed by October 1, 2004. 1a2, 3a1 - Evaluate combined effects of water and nitrogen amounts applied to a sandy soil on soil N, plant N, biomass production, and grain yield. Data will be used to enhance
algorithms to estimate soil N from remotely sensed canopy reflectance data to determine N amounts to apply for "spoon-feeding" the crop when and where needed. Analyze and interpret QuickBird satellite data provided by DigitalGlobe and its correlation to ground-based data for four simultaneous acquisitions during the 2003 corn growing season. Analyze remote sensed and plant based measurements taken on potatoes to determine usefulness of remote sensing for in-season N management for potatoes. Evaluate prototype active optical radiometers provided by Holland Scientific for possible mounting on a center-pivot system for any-time-of-day acquisition of plant canopy reflectance data. The water frequency/nitrogen study in a cooperator's field was not undertaken because of drought conditions; thus, the milestone to evaluate the combined effects of water and nitrogen on soil N, plant N, biomass production, and yield was not met and will not happen until a cooperator is located to conduct
this study. Analysis and interpretation of the QuickBird satellite data has been completed for the Yuma field site and two conference papers prepared; thus the milestone has been substantially met. Analysis of satellite data acquired at ARDEC has not been done because the person doing the image analysis left ARS for another job; image processing and analysis will be completed during FY05 for comparison to the Yuma site data. Remotely sensed data on potatoes to determine usefulness of remote sensing for in-season N management is progressing slowly. The remote sensed data is processed; however, the cooperating party has not completed the petiole NO3-N and leaf N analysis. Lab analyses will be completed in FY05 along with data interpretation. Evaluation of a prototype active optical sensor provided by Holland Scientific is currently underway. The sensor was received on June 11. A mounting bracket for hand-held operation was constructed and the sensor was interfaced with existing
data logging instrumentation to acquire location (latitude and longitude) of the measurement as well as the canopy reflectance values at the location. Data have been obtained three times on potatoes and corn and will continue for the remainder of each crops' growing season. Data is also being taken with a passive sensor (spectroradiometer) for comparison purposes. Data will be processed and analyzed during FY05. B. List the milestones (from the list in Question #2) that you expect to address over the next three years (FY2005, 2006, & 2007). What do you expect to accomplish, year by year over the next three years under each milestone? FY 2005 Milestone 1a1, 1c1, 1c2: Evaluate use of EC maps to infer the spatial variability of texture, soil water properties, and pesticide binding and leaching potentials. Work with the cooperator (new in 2004) to assess potential for using EC and yield maps collected in 2004 to change weed, water, and nutrient management. Identify and map EC of
fields with much different soil types to further assess potential for improving water and herbicide management. Milestone 1a2: Use active optical sensor and spectroradiometer to monitor canopy and plant N status of corn and potatoes. Evaluate mounting options of the active sensor on a center pivot sprinkler system. Finish analysis of satellite data to compare with corn canopy N status. Milestone 1a2, 1b1, 1d1: Analyze multi-site, multi-year EC, yield, and plant biomass and canopy N status estimates from remotely sensed data to determine if in-season and end-of-season plant parameters correlate with soil property estimates from EC measurements. Milestone 1b1, 2a1, 2b1: Evaluate the potential value of using a detailed soil-water-crop computerized model (RZWQM) to simulate water, nitrogen, and herbicide movement in irrigated sandy soils. Initial efforts will concentrate on compiling the past six years of field data from Wiggins and Yuma, constructing model input data files, and
calibrating RZWQM for the prevailing management and cropping systems. Milestone 1c1 and 2c1: 1. Evaluate weed management zones based on soil mapping and weed distribution in fields. 2. Develop maps on distribution of glyphosate-resistant weed populations in Colorado. 3. Determine relationship(s) between soil texture and EC that are useful in predicting herbicide behavior. 4. Determine the relationship between frequency of herbicide use and degradation of the herbicide in irrigated corn. 5. Evaluate the utility of active sensors on field equipment for identifying presence/absence of weeds and spraying as needed. 6. Test RZWQM predictions on herbicide behavior in field with data collected on herbicide movement and dissipation from two different fields. Milestone 2a2: Enhance CPED for new applicators and for entire field evaluation. Do more comprehensive testing of the existing model with NRCS and industry. Milestone 2c1: Quantify herbicide efficacy dissipation and leaching
potential under field conditions, coupled with detail laboratory soil column studies to evaluate herbicide behavior under varying management. Milestone 3b1: Upgrade the prototype irrigation and nitrogen scheduling program to include a nitrogen budget component and structured modularly in an object oriented language. Milestone 3b3: Explore with industry the addition of improved water management software as an integral part of irrigation system controls including adding improved water measurement devices. Milestone 4b1: The manufacturer has stopped all in-house research/development, production and marketing of its AccuPulse (AP) system, making it impossible for us to continue with equipment and software modifications for variable rate application. However, we will continue evaluating the value/benefits of variable application using a specially modified high- clearance tractor applicator capable of applying chemicals and/or liquid fertilizer like a center pivot as well as a conventional
ground applicator. Most of the efforts will be to design, do limited testing of applicator components, identify and test nozzles best suited for various application methods, and fabricate modifications, to have the tractor applicator operational for the 2005 field season. Will compare application uniformities for the various methods. If possible, establish field plot studies to: (1) evaluate the ability of spray system to apply variable rates of herbicides, (2) apply variable rates of herbicides based on soil EC map and compare efficacies with the uniform application of herbicides. FY 2006 Milestone 1a1, 1c1, 1c2: Continue working with additional farm cooperators on interpreting soil EC maps. Milestone 1a2, 1b1, 1d1: Continue multi-site, multi-year analysis of EC, yield, and various remotely sensed plant parameters with soil property estimates. Milestone 1a2: Evaluate robustness and reliability of an active optical sensing system mounted on a sprinkler system for acquiring data to
manage in-season N applications. Evaluate use of the active sensor for potential improvements in water management over traditional methods. Milestone 1b1, 2a1, 2b1: Evaluate the usefulness of detailed soil-water-crop models (RZWQM) to quantify the spatial and temporal variations in water and nitrogen in irrigated sandy soils with most efforts concentrated on RZWQM model evaluation and comparison of conventional uniform versus variable rate application methods. Milestone 1b2,1c1: Assess whether the distributions of weeds and weed seeds in a field are consistent enough over several years for predicting the distributions of future weed populations. If so, maps of the distribution of weed seeds and weeds in a field may be useful for prescribing site-specific weed management for several years. Milestones 1c1 and 2c1: 1. Evaluate cost-effectiveness of variable rate herbicide application based on EC zones and farmers' experience. 2. Determine impact of variable rate herbicide application
on ground and surface water contamination based on models and field measurements. 3. Complete development and evaluate cost-effectiveness and convenience of a video weed mapping system that growers and agricultural consultants can use to make weed maps for prescribing site-specific weed management. 4. Complete development and begin evaluating the accuracy and convenience of the weed mapping system using a digital camera mounted on a tractor or ATV. Milestone 2a1, 2c1: Use field data with physically based simulation models to estimate the environmental benefits of PF. Quantify herbicide efficacy dissipation and leaching in laboratory soil columns and under field conditions to further evaluate and refine modeling of herbicide behavior under varying management. Milestone 2a2: Begin updating standards for center pivot and linear move evaluations Milestone 3b1: Test prototype irrigation and nitrogen scheduling program. Develop a procedure for using remotely sensed data on nitrogen
status to update the nitrogen budget in the prototype program. Milestone 4b1: Use the modified high clearance tractor on field plot studies, to compare the performance and efficacy of various application methods (including AccuPulse) for nitrogen and pesticides. By strategically locating the various plots according to our variable rate criteria, the performance and value of variable rate application will be evaluated for the different application methods. FY 2007 Milestone 1a1, 1c1, 1c2: Complete the soil EC mapping studies and synthesize potential usefulness in precision farming. Evaluate use of weed mapping system for prescribing site-specific weed management Milestone 1b2, 1c1: Identify factors correlated with the distribution of weed seeds and seedlings within fields and investigate use of correlations for making weed maps. Milestones 1c1 and 2c1: 1. Document cost-effectiveness of variable rate herbicide application based on EC zones and farmers' experience. 2. Document impact
of variable rate herbicide application on ground and surface water contamination based on models and field measurements. 3. Train farmers on methods for implementing variable rate herbicide application. Milestone 2a1, 2c1, 4a1, 4b: Continue if necessary, use of the high-clearance tractor applicator on field plot studies to complete the evaluation of variable rate application methods. Estimate the environmental and economic benefits of variable rate application of agrochemicals using results from the FY05 and FY06 simulation modeling, laboratory and field studies. Milestone 2c1: Complete simulation experiments to assess the impact of site-specific weed management in irrigated corn on herbicide use, net return, crop yield loss from weed competition, and the number, species and distribution of weeds that are not controlled Milestone 3a1: Implement remotely sensed in-season N management on a commercial center- pivot irrigated corn field using active sensors to monitor and assess the
corn canopy N status. Milestone 3b3: In cooperation with industry, add improved water management software as an integral part of irrigation system controls. Milestone 4c1, 2c1: Modify software for evaluating the benefits of site-specific weed management (WeedSite) to create weed maps with GPS coordinates to more accurately evaluate the benefits of site-specific weed management and also to produce spatially referenced prescriptions that are needed for spatially variable application of herbicides Milestone 4d1: Generate variable N application maps from remotely sensed data and apply N based on these maps with the high-clearance tractor/sprayer. 4. What were the most significant accomplishments this past year? A. Single most significant accomplishment during FY 2004. The CPEDlite program for modeling the uniformity of center pivot sprinkler programs has been written to meet NRCS and industry requirements. It is included in the NRCS sprinkler conservation practice standard (442-1) to
evaluate center pivot performance. The model results of uniformity must be met by irrigation systems for cost sharing as part of their EQIP program to encourage the conservation of limited water resources. Several training sessions were presented to NRCS technicians and technical service providers for use of the program. Industry designers have developed programs that would take the output from their design programs and input to CPEDlite; saving a significant amount of time for the NRCS and their technical service providers in approving and evaluating proposed designs. Water conservation in NRCS targeted areas will be greatly enhanced by ensuring quality designs of systems that are cost shared with producers to save water and reduce pollution. B. Other Significant Accomplishments If EC maps are going to be useful in predicting soil-herbicide behavior, it is important that we be able to see differences across a number of fields. We made an EC map of a new field and then examined
the behavior of atrazine and dimethenamid in a high versus low EC zone. We found that there was a difference in the binding of these herbicides between the two zones and that the herbicides leached more in the low EC zone versus the high EC zone. The amount of glyphosate used has dramatically increased in recent years, increasing the chance of injury to sensitive crops due to drift. A leaf disc assay was developed that can be used to determine if a sensitive crop has been exposed to glyphosate if the plants are sampled within 10 days after exposure. There is increasing selection of glyphosate resistant weed populations due to the widespread adoption of glyphosate resistant crops. A leaf disc assay was developed that can be used to screen weeds for resistance to glyphosate. The system has been tested in the laboratory and the field and has shown potential as a relatively simple method for monitoring crop injury and to determine if a weed population has developed resistance to
glyphosate. Adjuvants are required to maximize the foliar activity of glyphosate. We have screened several adjuvants and have found that a certain acidifying agent increases the activity of glyphosate 2 to 3 fold. This acidifying agent works with all formulations of glyphosate. In addition, combining this acidifying agent with glyphosate has the potential to control glyphosate-resistant weeds, where the mechanism of resistance is due to decreased translocation of the herbicide to the site of action. Many satellite-based sensors have spatial resolutions too coarse for within field analysis and inadequate repeat coverage for intensive agricultural management. A cooperative study by the Water Management Research Unit and DigitalGlobe, Inc. compared high-resolution multispectral satellite data to ground-based multispectral data to determine if the QuickBird satellite could provide information on a crop's N status equivalent to the ground-based system. Satellite images and ground-based
data were acquired five times on a center-pivot irrigated corn field in eastern Colorado from June 24 to July 25, 2003. Results from three clear days of the five attempts to acquire satellite images suggest that the QuickBird satellite can be used for within field estimation of corn canopy N status; however, cloud cover over the area of interest is a hindrance to satellite data acquisition. First version of the software (WeedSite) has been completed and will be available for free on an ARS website as soon as herbicide databases are updated. With this software, corn growers can compare and map herbicide use and cost, net return, weeds left in the field with uniform and 4 different, postemergence site-specific weed management strategies based on had drawn weed maps. Further, we successfully structured the software so major components can be used for simulation experiments to assess the potential benefits of site-specific weed management and to prescribe spatially variable herbicide
applications from georeferenced weed maps. C. Significant Acomplishments/Activities that Support Special Target Populations. None D. Progress Report The project suffered a major set back due to the drought. Several of the cooperating farmers were unable to have a water supply and the fields were not in production during the 2003 growing season. New weed problems: Late emerging weeds. New weed management strategies, such as use of herbicide resistant crop or minimum tillage, are more cost-effective for controlling current problem weed species, but can result in other species becoming problems (weed shifts). If we can predict weed shifts, we can develop strategies to prevent shifts or minimize crop yield loss from shifts. Simulation experiments with a weed population dynamics model indicate weeds with extended periods of emergence or late emergence are most likely to become the new problem weeds in herbicide resistant crops. Mapping weed seed banks to reduce herbicide use. The
distribution of weed seeds within corn fields is patchy so soil- applied herbicide use may be reduced by targeting control for the patches, but mapping a seed bank to know where to spray is expensive. Mapping may be more cost-effective if we knew what determines size and shape of patches and how size and shape change over time. We compared the distribution of seed banks within 8 corn fields. Seed bank density, type of irrigation, how long seeds survive in the soil, adaptations for more extensive natural dispersal and seed size determined how large and oblong patches were. How patches change over time is likely influenced the most by whether seeds are spread by wind or tillage, or are just dropped around the parent plant. We now have information to predict distribution of weed seeds in a field and consequently, may be able to recommend ways to sample the seed bank to reduce the cost of mapping (1b2). 5. Describe the major accomplishments over the life of the project, including their
predicted or actual impact. The selection of herbicide resistant weed populations is increasing and there is a need to develop simple methods to determine if a weed population is resistant to certain herbicides so that an effective weed management program can be implemented. We have developed relatively simple leaf disc assays for determining resistance to ALS inhibitors, photosynthesis inhibitors and glyphosate. These assays have been used successfully used in the field to detect resistance all three classes of herbicides in different weed populations. Whole-field EC data from three commercial center pivot fields in Colorado were collected for 1998-2003 and analyzed using GIS and statistical packages. These analyses found strong relationships between yield and soil electrical conductivity (EC), but the relationships between EC and various soil productivity factors, were needed to be useful for site-specific management. The implementation of variable rate herbicide application
depends on finding a means to economically map soil variability in the field. Three significant results applicable to non- saline agricultural fields were found: 1) soil electrical conductivity maps are highly stable over time and do not require annual mapping, 2) soil electrical conductivity correlates strongly with texture (clay content), organic matter and soil water, and 3) the fields could be divided into herbicide binding zones based on soil EC, and subsequent sampling of areas of these fields that had not been previously sampled showed that we could predict herbicide binding with good accuracy. Field EC mapping provides a sound method of subdividing the field into yield response and soil management zones for the purpose of implementing variable-rate application of nutrients and pesticides to reduce input costs and enhance the environment. Spatial and temporal variability of soil N supply in conjunction with temporal variability of plant N demand makes conventional N
management difficult for site specific N applications. Soils in historically high and low yielding areas within a commercial center-pivot irrigated corn field in northeastern Colorado were sampled to determine NO3-N levels before and after the growing season to evaluate effectiveness of in- season N management based on remotely sensed crop N assessment. Crop N status was assessed at least weekly during vegetative growth to determine when to apply N. Applications of N based on remote sensing were 180 lb/ac less than the adjacent producer practice in the high yield area and 109 lb/ac less in the low yield area. These significant reductions in N application amounted to $50.40/ac in the high yield area and $30.50/ac in the low yield area at 2001 prices for N fertilizer. Residual NO3-N in the crop root zone was reduced by 117 lb/ac in the high yielding area and remained at similar levels for the low yielding area. In-season N application was reduced based on crop "need" while not
reducing grain yield, and crop root zone soil NO3-N levels were reduced which minimizes potential N leaching and degradation of the environment. The efficient application of chemicals is a challenge for farmers to maintain an economical production system while being good environmental stewards. Field studies with water sensitive paper have shown the coverage uniformity of AccuPulseTM to be comparable to conventional ground application and superior to aerial application. In many high value crops, fungicides that leave a chemical residue on leaves for disease protection, are applied multiple times either by air or chemigation. For chlorothalonil, a widely used fungicide on potatoes, foliage treated with AccuPulse had shown a 10 fold increase in residue compared to chemigation. Futhermore, the concentration of fungicide remaining on the leaves 7 days after application was greater on plants treated with AccuPulse, than on leaves 1 day after treatment with chemigation. These results
suggest that farmers can significantly reduce the number of applications of fungicides by utilizing AccuPulse while still maintaining efficacy for controlling diseases. Replicated plot studies were done within the cooperating farmer's field for 2 years, to determine whether yields in historically low yielding areas could be substantially increased by more intensive water and nitrogen management that minimized any water or nitrogen stress to the crop. Historical yield data were used to identify low (>=15% below mean), average, and high (>=15% above mean) productivity areas. In the first year, there was a 15% increase in corn yield in the low productivity area when supplemental water and nitrogen were applied to insure there was no water or nitrogen stress. In the second year, there was a 10% increase in potato yields in the low production area when 15% additional water was applied to relieve water stress between farmer-managed irrigations. Potato yields were not decreased when the
farmer practice of applying 90 lbs/ac of preplant nitrogen was omitted for a savings of $20.00 /ac in reduced fertilizer costs. These results indicate water is a significant factor affecting yield, but the additional cost of improved management and application technology probably limits the economic feasibility of adoption. Site-specific weed management is a technique for controlling weeds in crops with less herbicide by mapping the weed population in a field and then treating only the areas of a field where control is economically justified and varying management for the most efficient control when the species present varies within a field. However, growers cannot adopt this strategy until 1) they are confident that the benefits of site-specific weed management will exceed the costs, and 2) they have cost effective methods to make weed maps. Our research addresses both these obstacles so site-specific weed management can become a cost-effective method for growers to control weeds
with less herbicide. 1) The benefits of site- specific weed management vary with both the distribution of weeds in a field and the site-specific strategy used. We have developed software for growers to investigate the potential benefits of postemergence site- specific weed management in their irrigated corn fields. The software predicts the outcome of uniform and 4 different site-specific management strategies based on hand drawn weed maps. 2) In cooperation with a private company, we designed and are testing a low cost package (< $4000) of commercially available software and hardware for making weed maps. Our design is a digital camera mounted on a tractor or ATV with automated analysis of digital images to create a map of weed cover within a field. Growers and agricultural consultants need models to predict changes in the number, species and distribution of weeds in cropped fields in response to management so they can anticipate and mitigate weed problems that may be created by
using new weed management technologies. WISDEM is model developed by the ARS for this purpose. Scientists of the ARS Water Management Research Unit, Colorado State University and a private crop protection company, are modifying WISDEM to predict potential weed problems from use of herbicide resistant crops. They have developed expert opinion that can be used in lieu of missing and costly data on weed biology required by the model and are improving the model's interface for use by growers and agricultural consultants. With these changes, WISDEM can become a means to help safeguard and improve critical tools for cost-effective and environmentally sound weed management. 6. What science and/or technologies have been transferred and to whom? When is the science and/or technology likely to become available to the end- user (industry, farmer, other scientists)? What are the constraints, if known, to the adoption and durability of the technology products? Participated in 5 workshops with
major agrochemical companies, and growers on herbicide-soil interactions and how these interactions affect herbicide activity and dissipation. Participated in a workshops with a major agrochemical company on herbicide resistance and the utilization of leaf disc assays to measure resistance to ALS inhibitors and glyphosate. Participated in a special session at the 2004 Aquatic Plant Management Society on herbicide resistance management in aquatic systems. Information on in-season N management using ground-based and satellite remote sensing was presented to interested parties at a field day organized at the Yuma research site. Techniques for estimating plant N status from remotely sensed canopy reflectance have been transferred to the scientific community through presentations. Industry, consultants, and farmers can make use of this technology to determine when nitrogen applications should be made through use of commercial satellite data. Evaluation of a prototype active optical sensor
through an industry CRADA is underway to determine its use for anytime-of-day assessment of a crops' N status for in-season N management. The Center Pivot Evaluation and Design program has been distributed to NRCS, industry and other interested users via the internet for their use in evaluating uniformities of center pivot sprinkler systems. Presented training sessions on CPED for the NRCS at North Platte,NE and at the Central Plains Irrigation Association at Kearney, NE. Presented overview of Precision Farming at Workshops held at Lamar and Brush, Colorado. These workshops were attended by producers and action agency personnel. Provided soil EC maps and technical advice to the University of Wyoming for developing a new Ag Experiment Station farm. Presented research results on relating soil electrical conductivity data with soil water properties that could improve irrigation management at Extension Service sponsored field days in eastern Colorado. Equipment for measuring soil
electrical conductivity is commercially available. There is interest from some of the 'progressive' producers to map fields to aid in identifying and rectifying production problems related to the soil. Sound advice on interpreting EC is limited but should improve in the next 5 years as consultants and other ag service providers gain more experience. AccuPulse, an independent, low-volume chemical application system, mounted on a center pivot irrigation system, has been available to producers for several years. However, the manufacturer has stopped production and marketing of this system because of difficulties in providing technical support through their dealers and sluggish sales in the ag sector. The technology still appears to be viable technically but additional research and technical support are needed to help producers improve their level of management to fully utilize this technology. 7. List your most important publications in the popular press and presentations to
organizations and articles written about your work. Bausch, W.C. 2004. Comparison of multispectral analog and imaging systems for assessing plant nitrogen status in irrigated corn. Great Plains Soil Fertility Conference, March 2-3, Denver, CO. Bausch, W.C., K. Diker, J.F. Paris, and R. Khosla. 2004. Estimating plant nitrogen status in irrigated corn using ground-based and satellite data. Seventh International Conference on Precision Agriculture, July 25- 28, Minneapolis, MN. Bausch, W.C., K. Diker, R. Khosla, and J.F. Paris. 2004. Estimating corn nitrogen status using ground-based and satellite multispectral data. International Symposium on Optical Science and Technology, Aug. 2-4, Denver, CO. Diker, K., D.F. Heermann, G.W. Buchleiter, W.C. Bausch and H. Farahani. 2004. Modeling Yield by Neural Network. Seventh International Conference on Precision Agriculture, July 25-28, Minneapolis, MN. Heermann, D.F. 2004. Center Pivot Evaluation and Design. Proceedings of the 16th Annual
Central Plains Irrigation Conference. Febr. 17-18, 2004, Kearney, NE. pp. 1-15. Heermann, D. F. 2004. Center Pivot Irrigation System Evaluation and Design. AgEng 2004, September 12-16, Leuven, Belgium. Shaner, D.L., (2004) Challenges and Innovations in Weed Science for the 21st Century. Proceedings 15th International Plant Protection Congress, Beijing, China p.16. Shaner, D.L., (2004) Herbicide resistance management strategies for weeds. CAST Special Publication No. 24. pp. 143-145. Wiles, L. 2004. Sampling to Make Maps for Site-specific Weed Management. Presentation for symposium on Remote Sensing and Site- Specific Weed Management at the Annual Meeting of Weed Science Society of America. Wiles, L. 2003. Economics of Weed Management: Principles and Practices. Presentation for symposium on Contributions of Weed Science to Management of Invasive Species at the International Conference of Invasive Plants in Natural and Managed Systems: Linking Science and Management in
conjunction with 7th International Conference on Ecology and Management of Alien Plant Invasions.
Impacts
(N/A)
Publications
- DIKER, K., HENDERSON, S.A., BAUSCH, W.C., WRIGHT, D.K. RELATIONSHIP BETWEEN YIELD MONITOR AND REMOTELY SENSED DATA FOR CORN. ASAE ANNUAL INTERNATIONAL MEETING. 2003.
- HEERMANN, D.F., DIKER, K., BUCHLEITER, G.W., BRODAHL, M.K. THE VALUE OF ADDITIONAL DATA TO LOCATE POTENTIAL MANAGEMENT ZONES IN COMMERCIAL CORN FIELDS UNDER CENTER PIVOT IRRIGATION. EUROPEAN CONFERENCE ON PRECISION AGRICULTURE PROCEEDINGS. 2003.
- OZCAN, H., CETIN, M., DIKER, K. MONITORING AND ASSESSMENT OF LAND USE STAUS BY GIS. ENVIRONMENTAL MONITORING AND ASSESSMENT. 2003.
- UNLU, M., KANBER, R., DIKER, K., STEDUTO, P. COMPARING COTTON EVAPOTRANSPIRATIONS ESTIMATED BY MICROMETEOROLOGICAL AND WATER BUDGET METHODS. . 2001.
- Heermann, D.F., Diker, K., Buchleiter, G.W., Brodahl, M.K. 2003. The value of additional data to locate potential management zones in commercial corn fields under center pivot irrigation. European Conference on Precision Agriculture Proceedings.
- DIKER, K., BAUSCH, W.C. POTENTIAL USE OF NITROGEN REFLECTANCE INDEX TO ESTIMATE PLANT PARAMETERS AND YIELD OF MAIZE. BIOSYSTEMS ENGINEERING. 2003.
- DIKER, K., BUCHLEITER, G.W., FARAHANI, H., HEERMANN, D.F., BRODAHL, M.K. FREQUENCY ANALYSIS OF YIELD FOR DELINEATING MANAGEMENT ZONES. INTERNATIONAL CONFERENCE ON PRECISION AGRICULTURE ABSTRACTS & PROCEEDINGS. 2002.
- Koger III, C.H., Henry, W.B., Shaner, D.L. 2004. Shikimate accumulation in conventional corn and soybean as affected by sub-lethal rates of glyphosate. Meeting Abstract. Presented at the SWSS Annual Meeting. Jan. 23-30, 2004. Memphis, TN.
- Henry, W.B., Koger Iii, C.H., Shaner, D.L. 2004. Shikimate accumulation in conventional corn and soybean as affected by sub-lethal rates of glyphosate. Meeting Abstract. Presented at the WSSA 2004 Annual Meeting, February 2004. Kansas City, MO.
- Bausch, W.C., Delgado, J.A. 2003. Ground-based sensing of plant nitrogen status in irrigated corn to improve nitrogen management. Crop Science Society Of America.
- DIKER, K., BAUSCH, W.C. RADIOMETRIC FIELD MEASUREMENTS OF MAIZE FOR ESTIMATING SOIL AND PLANT NITROGEN. BIOSYSTEMS ENGINEERING. 2003.
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Progress 10/01/02 to 09/30/03
Outputs
1. What major problem or issue is being resolved and how are you resolving it? The major problem being addressed is how to minimize adverse environmental impacts from crop production systems while producing a reliable and safe food supply. Agricultural crop production has been identified as a major nonpoint source of water quality degradation because of contamination from pesticides and nitrates in groundwater resulting from excessive application of water, chemicals, and fertilizers. The National priority to provide an adequate supply of safe drinking water requires efforts to reduce quality degradation by various major water users. Increasing competition for land and water resources and increasing pressure to curtail or more closely regulate agricultural operations because of environmental concerns are forcing producers to consider alternative crop production systems to remain sustainable. Irrigation is a critical component of American agriculture since about 40%
of the nation's total crop value is produced on the 15% of the cropland that is irrigated. Precision agriculture is a management strategy that uses information technologies to bring data from multiple sources to bear on decisions associated with crop production. Small areas within a field are managed so only the needed amounts of fertilizer, chemicals, or water are applied in a timely manner rather that managing the entire field as a single unit, making uniform applications at the average or possibly maximum rate needed. Much of the commercial sector in Precision Farming (PF) is involved in developing equipment to collect large amounts of data, maps that visualize the data, and sophisticated equipment to variably apply crop production inputs. The part of the major problem that we are addressing is the development of integrated systems that can analyze these data to recommend scientifically based management strategies and deliver site specific applications of water, fertilizers, and
pesticides. Since more herbicide is applied than any other pesticide and nearly every acre of the major fields crops is treated, we are developing and evaluating sampling plans and bioeconomic weed management models. These tools will help growers determine whether weed control is economically justified and, if so, the most appropriate herbicide application for the weed population. Models and remote sensing technology for applying the right amount of water and fertilizer are being developed and evaluated. We are adapting sprinkler irrigation systems to apply chemicals such as fertilizers and pesticides when and where needed during the growing season. Producers can use this information to make and implement better management decisions that reduce water quality degradation and conserve soil and water resources while optimizing crop production. A multidisciplinary approach is necessary to get a better understanding of how various nutrient, water, pest, and climatic factors affect
yield variability. Our goal is to increase the scientific understanding of many of the interactions within the crop production system, so the appropriate data are analyzed correctly to make improved management decisions. Our approach is to study two commercial fields rather intensively over a 5+ year period. A combination of direct measurements and values calculated from calibrated models is used to quantify and map various parameters affecting yield. Two years of data without variable rate application technology (VRT) are used to establish a baseline scenario. Several years of data collected after implementing PF practices will provide the PF scenario. Comparison of these two scenarios will provide the basis for assessing the environmental impact and economic feasibility of PF. We are working with industry partners through CRADAs to develop and evaluate economical alternative data collection procedures to characterize soil and crop status as well as variable rate application
technologies for water, fertilizers, and pesticides that are economically feasible for producers to use. 2. How serious is the problem? Why does it matter? Public values demand a safe and reliable food supply and the public is voicing increasing concerns about the environmental impacts of agricultural activities on natural resources. Irrigation represents about 40% of the total annual fresh water use in the U.S. Since agriculture is a major water user, it is vulnerable to the increased competition for developed water supplies and available land caused by population growth and redistribution. Nearly half of the irrigated area in the Northern Plains is planted to corn and is typically fertilized with nitrogen. Most producers of high value crops, which are nearly all irrigated, apply herbicides to minimize the risk of reduced crop yield and quality. Herbicides are also viewed as inexpensive insurance against future weed problems, although the environmental impacts of this use, which
are difficult to quantify, may not be considered. Almost every acre of corn is treated with herbicides and the average application is two or more times per season. To remain competitive and economically viable, agricultural producers need new technologies to minimize their inputs and either reduce adverse impacts on the environment or document their wise stewardship of natural resources. Precision farming is currently being promoted by agribusiness as a way of improving management. Harvesters with global positioning systems (GPS) and yield monitors collect data to generate yield maps using geographical information system (GIS) technology. Intensive soil sampling and variable rate application of fertilizers are heavily promoted. If producers are to benefit from adopting PF, they must make significant capital investments in equipment and data collection activities as well as obtain the analytical expertise to translate the voluminous data into improved management decisions.
Generally, the science of interpreting and integrating the various kinds of PF data is not well understood and the environmental benefits that have been promised have not been well documented. Producers are not certain whether this new technology is technically or economically practical. Although preliminary PF research indicates herbicide use may be reduced 30 60% without affecting crop yield or quality, the economic feasibility should be carefully evaluated before producers make large capital investments for this and other PF management strategies. Water quality degradation and increase in water demand requires new knowledge and improved systems for using our water resources more efficiently to sustain production of high quality food and fiber. 3. How does it relate to the National Program(s) and National Program Component(s) to which it has been assigned? The project contributes to National Programs 201 Water Quality and Management, 202 Soil Resource Management, 207 Integrated
Farming Systems, 304 Crop and Commodity Pest Biology, Control and Quarantine, and 305 Integrated Crop Production and Protection Systems. This project contributes directly toward the theme for Precision Agriculture in the Irrigation and Drainage Management Systems component of NP 201. The approach of this theme is to study the entire production system including water, fertility, cultural, and pest control aspects to develop production systems and management strategies. Although irrigation systems can provide technology to complement precision farming, a multi disciplinary approach is needed to identify the spatial and temporal factors affecting yield variability and response functions. Research is needed to determine economically feasible sampling strategies and the appropriate size of management zones. Remote sensing with new rapid, economical sensors to measure variability of soil, water, and crop parameters may reduce the cost of obtaining necessary data. Needed scientific
management decisions must be delivered through automated variable rate equipment, including irrigation systems. This project also contributes to the themes for Environmental Quality Impacts, Irrigation in Humid Areas, Water Conservation Management and Salinity Management. The project contributes significantly to NP 207 but is being categorized under NP 201. NP 305, Integrated Crop Production and Protection Systems includes development of weed management systems, more effective sensor technology, and pesticide application technologies. Site specific weed management is potentially a cost effective strategy to reduce water contamination from agricultural lands (NP 201), improve food safety (NP 304) and facilitate the use of economic thresholds for weed management(NP 304). Factors affecting weed spatial distributions are being investigated to improve our ability to develop environmentally sound, site specific weed management techniques and methods to sample and map weed populations
(NP304). 4. What were the most significant accomplishments this past year? Previous work found strong relationships between yield and soil electrical conductivity (EC), but we needed to explore the practical utility of EC mapping to characterize the soil productivity factors for site-specific management. Whole-field EC data from three commercial center pivot fields in Colorado were collected for the 1998-2003 period and analyzed by the Water Management Unit, Fort Collins, CO using GIS and statistical packages. Two significant results applicable to non-saline agricultural fields were found: 1) soil electrical conductivity maps are highly stable over time and do not require annual mapping, and 2) soil electrical conductivity correlates strongly with texture (clay content), organic matter and soil water. Field EC mapping provides a sound method of subdividing the field into yield response and soil management zones for the purpose of implementing variable-rate application of nutrients
and pesticides to reduce input costs and enhance the environment. B. Other Significant Accomplishments Spatial and temporal variability of soil N supply in conjunction with temporal variability of plant N demand makes conventional N management difficult for site specific N applications. The Water Management Research Unit soil sampled historically low and high yielding areas within a commercial center-pivot irrigated corn field in northeastern Colorado to determine NO3-N levels before and after the growing season to evaluate effectiveness of in-season N management based on remotely sensed crop N assessment. Residual NO3-N in the crop root zone was reduced by 117 lb/ac in the high yielding area and remained at similar levels for the low yielding area. In-season N application was reduced based on crop "need" while not reducing grain yield, and crop root zone soil NO3-N levels were reduced which minimizes potential N leaching and degradation of the environment. The NRCS must approve
improvements in irrigation systems for cost sharing as part of their EQIP program to encourage the conservation of limited water resources. The National Water Management Engineer, NRCS in conjunction with the Water Management Unit convened a meeting with center pivot and sprinkler manufacturers to critique the new NRCS sprinkler standard which led. to the development of a version of CPED (center pivot evaluation and design program) for evaluating the adequacy of design of center pivot systems that would be eligible for cost sharing. CPEDlite is being used by the NRCS and manufacturers developed programs that would take the output from their design programs and input to CPEDlite; saving a significant amount of time for the NRCS and their technical service providers in approving and evaluating proposed designs. Water conservation in NRCS targeted areas will be greatly enhanced by ensuring quality designs of systems that are cost shared with producers to save water and reduce
pollution. Many high value crops are treated multiple times with fungicides applied either by air or chemigation in order to maintain disease control. A comparison of the efficiency of AccuPulse versus chemigation for applying chlorothalonil, a widely used fungicide, on potatoes showed that there was 10 fold more residue of chlorothalonil on foliage treated with AccuPulse compared to chemigation, and the concentration of fungicide remaining on the leaves 7 days after application was greater on plants treated with AccuPulse than on leaves 1 day after treatment with chemigation. These results suggest that farmers could reduce the number of applications of fungicides utilizing AccuPulse and still maintain efficacy. Herbicide resistance is a major problem in weed control and resistance to multiple herbicides is increasing in a number of species, such as kochia. A simple leaf disc assay to measure resistance to photosynthesis inhibitors was developed. This assay coupled with an in vivo
ALS assay was done on kochia plants collected from different fields and roadsides and revealed plants that were resistant to both classes of herbicides. These coupled assays promise to be a rapid, inexpensive way to determine the occurrence and spread of weed populations resistant to multiple herbicides. Plots studies were continued a second year within the cooperating farmer's field to determine whether yields in historically low yielding areas could be substantially increased by more intensive water and nitrogen management. Potato yields were increased by 10% in the sandier low yielding areas by applying about 15% additional water to relieve water stress between farmer managed irrigations. Potato yields were not decreased when the farmer practice of applying 90 lbs/ac of nitrogen preplant was omitted indicating a savings of $20.00 /ac in reduced fertilizer costs. Site-specific weed management (SSWM), such as leaving weed-free areas of a field untreated, may reduce herbicide use by
30 to 80% compared to a uniform application, but the reduction varies with both the distribution of weeds within a field and the strategy for varying weed management. A model was developed to simulate the outcomes of uniform and SSWM for irrigated corn in Colorado, and how much herbicide use could be reduced with several strategies for implementing SSWM was estimated from four years of observed weed distributions in two fields. Distributions of weeds were too uniform for SSWM in two cases, however, for three cases, the maximum possible reduction in herbicide use with SSWM was 46 to 60% and the estimated reduction with patch spraying was 14 to 47%. Variation in how much herbicide use was reduced with SSWM among years, fields and strategies indicates growers need information about the benefits of SSWM specifically for the strategies they will use and the nature of weed distributions in their fields. Growers may be able to control weeds with less herbicide with site- specific weed
management (SSWM), but many will need affordable, simple and convenient methods for making georeferenced weed maps because sprayers that detect weeds can be expensive and historic information on how weeds are distributed within a field can be valuable for prescribing SSWM. We developed and tested a system for making weed maps that uses commercially available video cameras, software, and GPS units and involves filming transects across a field while spraying or cultivating, capturing georeferenced frames of video for estimating percent weed biomass with image analysis and then interpolating between estimates for captured frames to make a map of the variation in weed biomass within a field. Transects were filmed prior to postemergence management in two summer fallow fields and one irrigated corn field using two adjacent cameras (true color and near infrared filtered). Percent biomass could be estimated from both types of video with simple procedures of image analysis so growers may be
able to map weed populations for SSWM without expensive and complex remote sensing equipment and image analysis software. The implementation of variable rate soil-herbicide application depends on finding a means to economically determine soil variability in the field and soil electrical conductivity (EC) could be such a method. The relationship between soil EC and herbicide binding of three different soil-applied herbicides was determined in three different fields. We found that we could divide the fields into herbicide binding zones based on soil EC, and subsequent sampling of areas of these fields that had not been previously sampled showed that we could predict herbicide binding with good accuracy. These results indicate that this relationship between soil EC maps and herbicide behaviors could be utilized to develop a practical method for creating variable rate herbicide maps. Variable rate application with the Accu-pulse chemical application system requires the control
sequence for implementation of the technology. The Water Management Unit used an ArcMap GIS model to develop the command sequence for variable rate application for Accu-pulse chemical application system. Maps that are created showing where the application rate should be changed based on management zones can be input to the model and the variable rate technology can be implemented with span by span control of the accu-pulse system installed on a center pivot irrigation system. C. Significant Acomplishments/Activities that Support Special Target Populations. None D. Progress Report The project suffered a major set back due to the drought. Several of the cooperating farmers were unable to have a water supply and the fields were not in production during the 2003 growing season. 6. What do you expect to accomplish, year by year, over the next 3 years? The selection of herbicide resistant weed populations is increasing and there is a need to develop simple methods to determine if a weed
population is resistant to certain herbicides so that an effective weed management program can be implemented. We developed a simple assay for determining resistance to sulfonylureas, imidazolinones and other herbicides with the same mechanism of action and used this assay to survey fields in Morgan and Weld counties in Colorado. We found widespread resistance in kochia populations in both counties. This assay provides a rapid and inexpensive way to determine if a weed population is resistant to certain herbicides so that a farmer can change his weed management program before the problem becomes widespread. Producers that have been adopting the tools (grain yield monitors and global positioning systems) of precision farming have become perplexed on how to use the large data sets and yield maps and have requested assistance in how to interpret them. The Water Management Unit in Fort Collins collected yields maps from multiple fields over four years and developed a simple procedure
that visually identifies the areas of the fields where yields are consistently high or low under different climactic conditions. These maps can be used by the producer to implement changes in management strategies that use other tools (e.g. variable rate applicators) of precision farming. These maps characterizing the yield performance of a field over multiple years are in important step in developing management strategies for environmental stewardship of our natural resources while maintaining the economical production of food and fiber for the consumer. Water quality is often degraded when nitrogen is used inefficiently by applying nitrogen (N) fertilizer to irrigated corn without adequate knowledge of soil N supply and crop N requirements. The Water Management Unit made weekly assessments of crop N status during vegetative growth in historically high and low yielding areas within a commercial field in northeastern Colorado to determine when to apply N. Applications of N based
on remote sensing were 109 lb/ac less than the adjacent producer practice in the low yield area and 180 lb/ac less in the high yield area, with essentially the same yields. Significant reductions in N applications amounting to $30.50/ac in the low yield area and $50.40/ac in the high yield area at 2001 prices are an environmental benefit, but the economic benefit to the producer will be less due to the cost of obtaining the data for determining the time to apply the fertilizer on a commercial farm. Site-specific weed management is a technique for controlling weeds in crops with less herbicide by treating only the areas of a field where control is economically justified and varying management for the most efficient control when the species present varies within a field, however, growers cannot adopt this technique without convenient and cost- effective methods to map the distributions of weeds in their fields. In cooperation with a private company, scientists in the Water Management
Research Unit designed a method for making weed maps that does not require an additional trip across a field to collect data, includes automated analysis and mapping of data, and uses technology that is available and growers can afford. We used the system to collect data on the weed populations in an irrigated and two dryland fields. If weed maps that are accurate enough for making management decisions can be created with this system, more growers will be able to adopt site-specific weed management because current methods for mapping the distribution of weeds in fields require expensive technology and specific technical expertise or are too time-consuming. We need models to predict changes in the number, species and distribution of weeds in cropped fields in response to management so we can anticipate and mitigate weed problems that may be created by using new weed management technologies and we can help growers with increasingly complex management decisions, but data on weed biology
needed to develop these models is scare and requires difficult and expensive long term experiments. Scientists of the ARS Water Management Research Unit, Colorado State University and a private crop protection company, developed a questionnaire to obtain expert opinion on how and why weed populations change with management. These scientists now have information that can be used in lieu of missing data to develop a model to predict weed problems with recently introduced new technologies such as herbicide resistant crops and improve an ARS model for evaluating weed management strategies for crop rotations. This model will help us safeguard and improve critical tools for cost-effective and environmentally sound weed management. Improved water management could be enhanced with an accurate, quick and low cost method to map water holding capacity. The Water Management Unit collected soil electrical conductivity (EC) data from three center pivot irrigated fields in northeastern Colorado
for 1998-2002 which were analyzed using geographic information systems (GIS) and statistical packages to identify EC patterns. The patterns in soil EC maps are highly stable over time and soil EC correlates strongly with texture (clay content), organic matter, and soil water in non-saline agricultural fields that can be used to estimate the water holding capacity. Thus EC mapping to identify water management zones with various water holding capacities, can be done infrequently, resulting in better maps and significant savings in data collection costs for producers to improve their water conservation and environmental stewardship. The efficient application of chemicals is a challenge for farmers to maintain an economical production system while being good environmental stewards. The Water Management Unit with CRADA partner Valmont Industry and a technology transfer/energy conservation study for the Department of Energy and the Colorado Corn Growers Association, have conducted
comparison studies and measured uniformity of a 7 tower AccPulseTM system with water sensitive cards and have made comparisons with conventional ground and aerial applicators and have tracked the pesticide residue at several levels in the crop canopy. The results demonstrate the comparability of the AccuPulse technology for producers to apply chemicals during the season with reduced wind drift potential. Summary: Future plans: FY04 Determination of feasibility of weed management zones utilizing variable rate application of soil applied herbicides based on soil EC. Measure the effects on efficacy dissipation and leaching potential under field conditions. Development of field assays for measuring resistance to herbicides other than ALS inhibitors and surveys of weed populations in the field. Testing of current models' prediction of herbicide behavior under laboratory and field conditions. Begin any software development required to implement variable rate application with the
AccuPulse system. Determine the methods for increasing the coverage of spray droplets applied via AccuPulse such as adjuvants, spreader design, etc, without compromising anti-drift potential of system. Distribution of computer software that growers, agricultural consultants and other decision makers can use to evaluate how much herbicide use may be reduced with site-specific weed management in their irrigated corn fields and the impact on crop yield and weeds left in the field that will produce seed. Growers will also be able to compare the outcomes of several strategies for dividing the field into areas that may be managed differently. Determine the position of the camera for most accurate mapping of weed populations with an inexpensive system using a video camera mounted on a tractor. Also, assess whether video mapping of weeds is accurate enough for making management decisions. Work with several cooperators to field test the best analytical techniques for interpreting EC data and
relating it to soil parameters affecting the water holding capacity Complete testing of an integrated irrigation and nitrogen budgeting prototype program that contains appropriate science as well as capabilities for updating water and nitrogen amounts based on real-time feedback. Complete evaluation of the application performance of a complete 7 tower AccuPulse' system primarily in the laboratory. Initiate software development required to implement variable rate application with the AccuPulse system. Evaluate combined effects of water and nitrogen amounts applied to a sandy soil on soil N, plant N, biomass production, and grain yield. Data will be used to enhance algorithms to estimate soil N from remotely sensed canopy reflectance data to determine N amounts to apply for "spoon- feeding" the crop when and where needed. Analyze and interpret QuickBird satellite data provided by DigitalGlobe and its correlation to ground- based data for four simultaneous acquisitions during the 2003
corn growing season. Analyze remote sensed and plant based measurements taken on potatoes to determine usefulness of remote sensing for in-season N management for potatoes. Evaluate prototype active optical radiometers provided by Holland Scientific for possible mounting on a center-pivot system for any-time-of-day acquisition of plant canopy reflectance data. FY05 Transfer of information on variable rate application of soil applied herbicides to farmers and custom applicators based on soil properties. Development of weed management zones based on soil mapping and weed distribution in fields. Development of maps on distribution of herbicide resistant weed populations in Colorado and recommendations for resistant weed management. Conduct on farm research by mapping EC of new fields, determining relationship between soil texture and EC and predicting herbicide behavior, and applying variable rates of herbicides and monitoring efficacy, leaching, and dissipation. Evaluate the
performance of AccuPulse for variable rate application of pesticides. Monitor distribution on soil and foliage and efficacy on pests. Develop a technique to assess the benefits of site-specific weed management and use the technique to evaluate the impact of site-specific weed management in irrigated corn on herbicide use, crop yield loss from weed competition, and the number, species and distribution of weeds that are not controlled. Assess whether the distributions of weeds and weed seeds in a field are consistent enough over several years for predicting the distributions of future weed populations. If so, maps of the distribution of weed seeds and weeds in a field may be useful for prescribing site-specific weed management for several years. Continue working with several cooperators on interpreting EC data as well as using the water and nitrogen management prototype program. Develop variable rate capability for AccuPulse system Develop protocols for data analyses that could assist
producers in determining the feasibility of PF for individual fields. The economic aspect would look at potential for increased yields across a field by identifying the causes and areas of yield loss as well as the necessary costs for increasing yield. The environmental aspect would identify the potential reduction in percolation below the root zone and of leached nutrients. Implement remotely sensed nitrogen management on at least half of a commercial sprinkler irrigated corn field to apply nitrogen as needed by the crop and where needed within the field. Evaluate use of remote sensed data to determine potential improvements in water management over traditional methods. Initiate N management on potatoes in small areas of a commercial potato field using remotely sensed data. Continue efforts toward mounting and evaluating a real-time active optical sensing system on center pivots. FY06 Evaluate cost-effectiveness of variable rate herbicide application based on EC zones and farmers'
experience. Determine impact of variable rate herbicide application on ground and surface water contamination based on models and field measurements. Complete development and evaluate cost-effectiveness and convenience of a video weed mapping system that growers and agricultural consultants can use to make weed maps for prescribing site-specific weed management. Evaluate the performance of AccuPulse for variable rate application of pesticides. Use field data with physically based simulation models to estimate the environmental benefits of PF. Implement remotely sensed water and nitrogen management on a commercial center-pivot irrigated corn field using high resolution satellite data. Evaluate robustness and reliability of a real-time active optical sensing system mounted on a sprinkler system for acquiring data to manage water and nitrogen applications. 7. What science and/or technologies have been transferred and to whom? When is the science and/or technology likely to become
available to the end- user (industry, farmer, other scientists)? What are the constraints, if known, to the adoption and durability of the technology products? Valmont Industries, our CRADA partner, is currently marketing the AccuPulse' system commercially, primarily to producers of high value crops. One possible constraint to the adoption of this technology is economic. Depending on the cost of alternative application methods and the amount of chemicals typically applied to a crop, this technology may not be economically feasible for lower value crops. Since high value crops are usually rotated with low value crops under self-propelled sprinklers, improving the portability of this system so it could be quickly removed and re-installed on high value crops would enhance the economic feasibility and marketability. Commercial equipment for measuring soil electrical conductivity is currently available. Since EC mapping of a field may not need to be done every year, consultants charging
a fee or farmers cooperatives that rent equipment to their members, are probably the most likely candidates for using this technology. A few 'early adopter' producers are mapping soil EC but their interpretation of the data is limited. Procedures for interpreting and correlating the EC data should be available in the next 5 years, so that researchers, consultants, and some producers will be able to utilize the EC data to improve their understanding of the causes of yield variability. A computerized irrigation scheduling program has been used by a small but increasing number of farmers over the past 15 years. The prototype program currently under development is Windows based with a graphical interface for the user. This prototype is being tested probably available next year for use or adoption by software developers of farm management packages. Our intent is to identify and make available the appropriate technology to software developers for the commercial market. A consulting
company (Agro Engineering, Inc.) in southern Colorado is using the N Reflectance Index as a crop health indicator on approximately 400 fields in the San Luis Valley; each field is flown three to four times during the growing season. The company has also flown 50 fields around Yuma, CO and 40 fields around Grand Island, NE. It is our goal to begin to work with farmers as not only research clients but also as research partners. We have begun to develop a network of farmers using precision farming technologies to facilitate on- farm research. A focus group met with the project scientists in January and July, 2002. Project results and progress were reported. The focus group is composed of producers and industry, regulators, legislators, and other community participants. Results of on-going remote sensing studies for improved nitrogen management presented at focus group meetings. Field days were organized at project research sites (Wiggins, Yuma, and Greeley, Colorado) to present the
project details and project findings to the producers and other interested parties. Four scientists are involved with Cooperative Research And Development Agreements (CRADA) with industry, including: field evaluation of a system to manage nitrogen fertilizer applications in corn production; investigating use of hyperspectral canopy reflectance for real-time assessment of plant stresses; evaluating a prototype data logger for the SPAD chlorophyll meter that interfaces GPS positions; and developing and evaluating positioning systems for linear move sprinklers and sprinkler attached spatially variable chemical application systems. A CRADA partner is providing us with tools for the spatial analysis of the many layers collected on the two center pivot irrigated fields. We are providing data for the partner to assist in the development and testing of their new products. As we use these products we will provide feedback to our partner in their development of improved analytical tools for
the application of precision agricultural technology. Various techniques for estimating plant nitrogen status from remotely sensed canopy reflectance have been transferred to the scientific community through presentations. Industry, consultants, and the farmer can make use of this technology to determine when nitrogen applications should be made. The main constraint to adoption of the technique is the current lack of an economical means of acquiring canopy reflectance data on a repeated schedule. Commercialization of satellite acquired data has not had a very good start. 8. List your most important publications in the popular press and presentations to organizations and articles written about your work. (NOTE: This does not replace your peer-reviewed publications listed below). Presentations: Heermann, D.F. (2003). CPED and CPED LITE demonstration and discussion. Irrigation Forum, North Platte West Central Research and Extension Center, North Platte, NE. Heermann, D.F. (2003).
New Irrigation Water Conservation Technologies. 15th Annual Ag Conference, Colorado Springs, CO. Heermann, D.F. (2003). A Reflection on Irrigation Changes. 15th Annual Central Plains Irrigation Conference Exposition Proceedings, Colby Kansas. p. 16-28. Heermann, D.F., F. Lamm (2003). History of CPIR. 15th Annual Central Plains Irrigation Conference Exposition Proceedings, Colby Kansas. p. 29-36. Buchleiter, G.W. (2003). The AccuPulse chemical application system has been demonstrated to consultants, agency personnel, and growers at local field days, and at Extension sponsored workshops related to irrigation management and precision farming. Diker, K., Heermann D.F. and Buchleiter, G.W. (2003). Analysis of multi year yield data for delineating yield response zones. ASAE international meeting. Las Vegas, NV Publications: Barnes, E.M., K.A. Sudduth, J.W. Hummel, S.M. Lesch, D.L. Corwin, C. Yang, C.S. Daughtry, and W.C. Bausch. (2003). Remote- and ground-based sensor techniques to
map soil properties. Photogrammetric Engineering and Remote Sensing, 69(6):619-630. Bausch, W.C. and J.A. Delgado. (2003). Ground-based sensing of plant nitrogen status in irrigated corn to improve nitrogen management. CSSA Special Publication "Digital Imaging and Spectral Techniques. Applications to Precision Agriculture and Crop Physiology". (Accepted for publication June 23, 2003). Heermann. D.F., K. Diker, G.W. Buchleiter and M.K. Brodahl (2003) The value of additional data to locate potential management zones in commercial corn fields under center pivot irrigation. In: J. Stafford, J. Warner (eds.) Proceedings of 4th European Conference on Precision Agriculture, Berlin, Germany. p. 279-284. Kitchen N. R., S.T. Drummond, E.D. Lund, K. A. Sudduth, G. W. Buchleiter. 2003. Soil electrical conductivity and other soil and landscape properties related to yield for three contrasting soil and crop systems. Agronomy Journal (Accepted for publication Nov 7, 2002) Moran, S., G.
Fitzgerald, A. Rango, C. Walthall, E. Barnes, W. Bausch, T. Clarke, C. Daughtry, J. Everitt, D. Escobar, J. Hatfield, K. Havstad, T. Jackson, N. Kitchen, W. Kustas, M. McQuire, P. Pinter, Jr., K. Sudduth, J. Schepers, T. Schmugge, P Starks, and D. Upchurch. (2003). Sensor development and radiometric correction for agricultural applications. Photogrammetric Engineering and Remote Sensing, 69(6):705-718. Schleicher, T.D., W.C. Bausch, and J.A. Delgado. (2003). Low ground cover filtering to improve reliability of the Nitrogen Reflectance Index (NRI) for corn N status classification. Transactions of the ASAE (Accepted Aug. 13, 2003). Shaner, D.L., 2003. Herbicide safety relative to common targets in plants and mammals. Pest Management Science. In press. Shaner, D.L. Imidazolinone herbicides In Encyclopedia of Agrochemicals J. Plimmer (Ed.) John Wiley and Sons, New York. Canner, S.R., L.J. Wiles and G.S. McMaster. Weed reproduction model parameters may be estimated from crop yield
loss data. Weed Science. 2002. v. 50. p. 773-772. Wyse-Pester, D.Y., L.J. Wiles and P. Westra. The potential for mapping nematode infestations. Journal of Nematology 2002. v. 34. p. 80-87. Wiles, L.J., D.K. Wright and K. Diker. Mapping weed populations with video for site-specific weed management. Western Society of Weed Science. 2003. Abstract. Diker, K. and Bausch, W.C. 2003. Potential use of nitrogen reflectance index to estimate plant variables and yield of corn. Biosystems Engineering, 85(4), 437-447. Ozcan, H., Cetin, M. and Diker, K. 2003. Monitoring and assessment of land use status by GIS. Environmental Monitoring and Assessment, 87(1), 33-45. Cetin, M. and Diker, K. 2003. Assessing drainage problem areas by GIS: A case study in the eastern Mediterranean region of Turkey. Irrigation and Drainage (In press) Farahani, H.J. and G.W. Buchleiter. 2003. Temporal stability of bulk soil electrical conductivity in irrigated sandy fields in Colorado. ASAE Transactions.
Accepted.
Impacts
(N/A)
Publications
- Shaner, D.L., and B. Tecle. Designing herbicide tolerance based on metabolic alteration: The challenges and the future. In "Pesticide Biotransformation in Plants and Microorganisms", J.C. Hall, R.E. Hoagland, and R.M. Zablotowicz, eds. ACS Symposium Series 777. Oxford University Press, Oxford. 2001 Pp. 353 374.
- Powles, S.B., and D.L. Shaner. Herbicide resistance and world grains. CRC Press, Boca Raton, FL. 2001, 308p.
- Shaner, D. L. and P. Leonard. Regulatory aspects of resistance management for herbicides and other crop protection products. In "Herbicide Resistance and World Grains" S.L Powles and D.L. Shaner, eds. CRC Press, Boca Raton, FL. 2001, Pp. 279 294.
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Progress 10/01/01 to 09/30/02
Outputs
1. What major problem or issue is being resolved and how are you resolving it? The major problem being addressed is how to minimize adverse environmental impacts from crop production systems while producing a reliable and safe food supply. Agricultural crop production has been identified as a major nonpoint source of water quality degradation because of contamination from pesticides and nitrates in groundwater resulting from excessive application of water, chemicals, and fertilizers. The National priority to provide an adequate supply of safe drinking water requires efforts to reduce water quality degradation by various major water users. Increasing competition for land and water resources and increasing pressure to curtail or more closely regulate agricultural operations because of environmental concerns are forcing producers to consider alternative crop production systems to remain sustainable. Irrigation is a critical component of American agriculture since
about 40% of the nation's total crop value is produced on the 15% of the cropland that is irrigated. Precision agriculture is a management strategy that uses information technologies to bring data from multiple sources to bear on decisions associated with crop production. Small areas within a field are managed so only the needed amounts of fertilizer, chemicals, or water are applied in a timely manner rather that managing the entire field as a single unit, making uniform applications at the average or possibly maximum rate needed. Much of the commercial sector in Precision Farming (PF) is involved in developing equipment to collect large amounts of data, maps that visualize the data, and sophisticated equipment to variably apply crop production inputs. The part of the major problem that we are addressing is the development of integrated systems that can analyze these data to recommend scientifically based management strategies and deliver site specific applications of water,
fertilizers, and pesticides. Since more herbicide is applied than any other pesticide and nearly every acre of the major fields crops is treated, we are developing and evaluating sampling plans and bioeconomic weed management models. These tools will help growers determine whether weed control is economically justified and, if so, the most appropriate herbicide application for the weed population. Models and remote sensing technology for applying the right amount of water and fertilizer are being developed and evaluated. We are adapting sprinkler irrigation systems to apply chemicals such as fertilizers and pesticides when and where needed during the growing season. Producers can use this information to make and implement better management decisions that reduce water quality degradation and conserve soil and water resources while optimizing crop production. A multidisciplinary approach is necessary to get a better understanding of how various nutrient, water, pest, and climatic
factors affect yield variability. Our goal is to increase the scientific understanding of many of the interactions within the crop production system, so the appropriate data are analyzed correctly to make improved management decisions. Our approach is to study two commercial fields rather intensively over a 5+ year period. A combination of direct measurements and values calculated from calibrated models is used to quantify and map various parameters affecting yield. Two years of data without variable rate application technology (VRT) are used to establish a baseline scenario. Several years of data collected after implementing PF practices will provide the PF scenario. Comparison of these two scenarios will provide the basis for assessing the environmental impact and economic feasibility of PF. We are working with industry partners through CRADAs to develop and evaluate economical alternative data collection procedures to characterize soil and crop status as well as variable rate
application technologies for water, fertilizers, and pesticides that are economically feasible for producers to use. 2. How serious is the problem? Why does it matter? Public values demand a safe and reliable food supply and the public is voicing increasing concerns about the environmental impacts of agricultural activities on natural resources. Irrigation represents about 40% of the total annual fresh water use in the U.S. Since agriculture is a major water user, it is vulnerable to the increased competition for developed water supplies and available land caused by population growth and redistribution. Nearly half of the irrigated area in the Northern Plains is planted to corn and is typically fertilized with nitrogen. Most producers of high value crops, which are nearly all irrigated, apply herbicides to minimize the risk of reduced crop yield and quality. Herbicides are also viewed as inexpensive insurance against future weed problems, although the environmental impacts of this
use, which are difficult to quantify, may not be considered. Almost every acre of corn is treated with herbicides and the average application is two or more times per season. To remain competitive and economically viable, agricultural producers need new technologies to minimize their inputs and either reduce adverse impacts on the environment or document their wise stewardship of natural resources. Precision farming is currently being promoted by agribusiness as a way of improving management. Harvesters with global positioning systems (GPS) and yield monitors collect data to generate yield maps using geographical information system (GIS) technology. Intensive soil sampling and variable rate application of fertilizers are heavily promoted. If producers are to benefit from adopting PF, they must make significant capital investments in equipment and data collection activities as well as obtain the analytical expertise to translate the voluminous data into improved management
decisions. Generally, the science of interpreting and integrating the various kinds of PF data is not well understood and the environmental benefits that have been promised have not been well documented. Producers are not certain whether this new technology is technically or economically practical. Although preliminary PF research indicates herbicide use may be reduced 30 60% without affecting crop yield or quality, the economic feasibility should be carefully evaluated before producers make large capital investments for this and other PF management strategies. Water quality degradation and increase in water demand requires new knowledge and improved systems for using our water resources more efficiently to sustain production of high quality food and fiber. 3. How does it relate to the national Program(s) and National Program Component(s) to which it has been assigned? The project contributes to National Programs 201 Water Quality and Management, 202 Soil Resource Management, 207
Integrated Farming Systems, 304 Crop and Commodity Pest Biology, Control and Quarantine, and 305 Integrated Crop Production and Protection Systems. This project contributes directly toward the theme for Precision Agriculture in the Irrigation and Drainage Management Systems component of NP 201. The approach of this theme is to study the entire production system including water, fertility, cultural, and pest control aspects to develop production systems and management strategies. Although irrigation systems can provide technology to complement precision farming, a multi disciplinary approach is needed to identify the spatial and temporal factors affecting yield variability and response functions. Research is needed to determine economically feasible sampling strategies and the appropriate size of management zones. Remote sensing with new rapid, economical sensors to measure variability of soil, water, and crop parameters may reduce the cost of obtaining necessary data. Needed
scientific management decisions must be delivered through automated variable rate equipment, including irrigation systems. This project also contributes to the themes for Environmental Quality Impacts, Irrigation in Humid Areas, Water Conservation Management and Salinity Management. The project contributes significantly to NP 207 but is being categorized under NP 201. NP 305, Integrated Crop Production and Protection Systems includes development of weed management systems, more effective sensor technology, and pesticide application technologies. Site specific weed management is potentially a cost effective strategy to reduce water contamination from agricultural lands (NP 201), improve food safety (NP 304) and facilitate the use of economic thresholds for weed management(NP 304). Factors affecting weed spatial distributions are being investigated to improve our ability to develop environmentally sound, site specific weed management techniques and methods to sample and map weed
populations (NP304). 4. What was your most significant accomplishment this past year? The selection of herbicide resistant weed populations is increasing and there is a need to develop simple methods to determine if a weed population is resistant to certain herbicides so that an effective weed management program can be implemented. We developed a simple assay for determining resistance to sulfonylureas, imidazolinones and other herbicides with the same mechanism of action and used this assay to survey fields in Morgan and Weld counties in Colorado. We found widespread resistance in kochia populations in both counties. This assay provides a rapid and inexpensive way to determine if a weed population is resistant to certain herbicides so that a farmer can change his weed management program before the problem becomes widespread. B. Other Significant Accomplishments C. Significant Acomplishments/Activities that Support Special Target Populations. None D. Progress Report The majority of
this project is reported for CRIS 5402-13220-001-00D. The accomplishment in this report was that from Dale Shaner, a weed scientist that joined the Water Management Unit in December 2001 and his major efforts were toward the objectives of the new project. 5. Describe your major accomplishments over the life of the project, including their predicted or actual impact? The major accomplishments for this project which began 2/15/2002 are in the report for Project 5402-13220-001-00D. This project is a continuation of the work in the previous project. 6. What do you expect to accomplish, year by year, over the next 3 years? FY03: Variability in yield has been found to relate to the soil electrical conductivity (EC). The relationship between EC and soil properties such as water content, organic matter and texture are being quantified. The relationship of EC to manageable factors such as herbicide binding, leaching potential and biological efficacy will be used for new and improved
management strategies to enhance the environment. Complete initial testing of uniformity of both concentration and coverage of chemicals applied using the AccuPulse application system . Guidelines will be provided for growers to select the appropriate chemical application system. FY04 Test an integrated irrigation and nitrogen budgeting prototype for new nitrogen management technologies. The remotely sensed nitrogen management technology will be tested simultaneously in producers fields. Multi year impacts will be simulated. FY05 Protocols for remote sensing data collection for improved nitrogen management will be developed. Develop and evaluate weed maps for the variable rate application of herbicides to control the spatial weed distribution. Transfer technology to producers.` Test AccuPulse chemical application for variable rate chemical application that should provide a commercial tool for PF. Future plans: FY03 Determination of the relationship between soil EC and herbicide
binding, leaching potential and biological efficacy. Application of current models to determine feasibility of mapping herbicide use rates within a field based on soil EC data. Determination of the effect of adjuvants on spray retention and distribution applied through the AccuPulse system on plants under field conditions. Survey of weed populations within Colorado for resistance to ALS inhibiting herbicide utilizing in vivo ALS assay field kit. Distribution of computer software that growers, agricultural consultants and other decision makers can use to evaluate how much herbicide use may be reduced with site-specific weed management in their irrigated corn fields and the impact on crop yield and weeds left in the field that will produce seed. Growers will also be able to compare the outcomes of several strategies for dividing the field into areas that may be managed differently. Continue development of algorithms to estimate soil N (in cooperation with unit colleagues) from
remotely sensed canopy reflectance data in order to determine N amounts to apply for spoon-feeding the crop. Determine crop response time to N applied via fertigation using 15N tagged fertilizer (in cooperation with SPNR scientists) to establish necessary lead time for N application decisions using the NRI. Remote sensing efforts on potatoes will continue in order to develop techniques to detect nitrogen status of the crop for improved N management during the growing season. Investigate mounting optical sensors on a sprinkler system for ground-based sensing. Complete work of quantifying relationships between soil electrical conductivity and soil properties (including water content, organic matter, and texture) for a variety of soil types. Primary effort will involve evaluating several analytical techniques that quantify the contributions of various parameters to soil EC. It is anticipated that by using electrical conductivity, we can more economically map soil surface and profile
properties than the traditional direct soil core sampling. Finish development and begin testing of an integrated irrigation and nitrogen budgeting prototype program that contains appropriate science as well as capabilities for updating water and nitrogen amounts based on real-time feedback. Quantify potential benefits of precision irrigation, nitrogen and pesticide application by using existing farm and research level models (such as the ARS models GPFARM and RZWQM and CPED) with detailed field data. Evaluate the application performance of a complete 7 tower AccuPulse? system primarily in the laboratory. Both computer simulations and measured data will be used to determine the uniformity of chemical applied. FY04 Determination of feasibility of weed management zones utilizing variable rate application of soil applied herbicides based on soil EC. Measure the effects on efficacy dissipation and leaching potential under field conditions. Development of field assays for measuring
resistance to herbicides other than ALS inhibitors and surveys of weed populations in the field. Testing of current models' prediction of herbicide behavior under laboratory and field conditions. Develop a technique to assess the benefit of site-specific weed management and use the technique to evaluate the impact of site-specific weed management in irrigated corn on herbicide use, crop yield loss from weed competition, and the number, species and distribution of weeds that are not controlled. Assessment of whether the distributions of weeds and weed seeds in a field are consistent enough over several years for predicting the distributions of future weed populations. If so, maps of the distribution of weed seeds and weeds in a field may be useful for prescribing site- specific weed management for several years. Implement remotely sensed nitrogen management on at least half of a commercial sprinkler irrigated corn field to apply nitrogen as needed by the crop and possibly where needed
within the field (depends on AccuPulse development/modification by colleagues in the unit). Initiate N management on potatoes in small areas of a field using remotely sensed data. Continue efforts toward developing a real-time optical sensing system on sprinklers for any time of day operation. Work with several cooperators to field test the best analytical techniques for interpreting EC data. Assist several cooperators in using the water and nitrogen management prototype program and evaluate its effectiveness for improving irrigation management. Begin any software development required to implement variable rate application with the AccuPulse system. Develop protocols for data analyses that could assist producers in determining the feasibility of PF for individual fields. The economic aspect would look at potential for increased yields across a field by identifying the causes and areas of yield loss as well as the necessary costs for increasing yield. The environmental aspect would
identify the potential reduction in percolation below the root zone and of leached nutrients. Continue the water quality modeling efforts by validating the 2003 calibrated models against multi-year field data. An accurately validated model and parameter values will then be selected to evaluate alternate management strategies of precision irrigation and chemical application. FY05 Transfer of information on variable rate application of soil applied herbicides to farmers and custom applicators based on soil properties. Development of weed management zones based on soil mapping and weed distribution in fields. Development of maps on distribution of herbicide resistant weed populations in Colorado and recommendations for resistant weed management. Develop techniques growers and agricultural consultants can use to make weed maps for prescribing site-specific weed management that minimize the need for the expensive and time-consuming task of locating, assessing density and species and
mapping weed patches in a field. The foundation of the techniques will be fundamental knowledge from ongoing basic research of this project on how the distribution of weeds in a field changes over time and the effect of management and field characteristics on the size, shape and composition of weed patches. Evaluate robustness and reliability of a prototype real-time optical sensing system mounted on a sprinkler system for acquiring data to manage in-season N applications. Continue working with several cooperators on interpreting EC data as well as using the water and nitrogen management prototype program. Evaluate the performance of AccuPulse for variable rate application of pesticides. Use field data with physically based simulation models to estimate the environmental benefits of PF. Evaluate the water quality and chemical injection model results for testing on-farm management scenarios. The precision water and nitrogen scenarios will be at two levels. The first level will be a
set of modifications of the timing and amount of irrigation and nitrogen application to quantify the impact of a more precise application as compared to the existing system. The second level of modeling will concentrate on "variable rate technology" in that the agricultural inputs of water and chemicals will have a spatial component. The models will be used to determine and compare the spatial and temporal variability of components of water and nitrogen budgets under conventional uniform (existing system) and precision irrigation and nitrogen application. 8. List your most important publications and presentations, and articles written about your work (NOTE: this does not replace your review publications which are listed below) Shaner, D.L. Development and utilization of a high throughput in vivo AHAS assay. February, 2002. Weed Science Society of America. Reno, NV. Shaner, D.L. Analyzing and understanding the management of ALS-resistant plants. February, 2002. National
Railroad Contractors Association. West Lafeyette, IN. Shaner, D.L., Herbicide safety Relative To common targets in plants and mammals. August, 2002 International Union of Pure and Applied Chemistry, Basel, Switzerland and American Chemical Society Boston, MA.
Impacts
(N/A)
Publications
- Shaner, D.L., and B. Tecle. Designing herbicide tolerance based on metabolic alteration: The challenges and the future. In "Pesticide Biotransformation in Plants and Microorganisms", J.C. Hall, R.E. Hoagland, and R.M. Zablotowicz, eds. ACS Symposium Series 777. Oxford University Press, Oxford. 2001 Pp. 353 374.
- Powles, S.B., and D.L. Shaner. Herbicide resistance and world grains. CRC Press, Boca Raton, FL. 2001, 308p.
- Shaner, D. L. and P. Leonard. Regulatory aspects of resistance management for herbicides and other crop protection products. In "Herbicide Resistance and World Grains" S.L Powles and D.L. Shaner, eds. CRC Press, Boca Raton, FL. 2001, Pp. 279 294.
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