Progress 03/01/07 to 10/21/11
Outputs
Target Audience:
Nothing Reported
Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?
Nothing Reported
How have the results been disseminated to communities of interest? Results were disseminated via field days, conference papers and presentations as well as publications and in the classroom. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
Results and output from research collected and reported during the period for this project included technical papers presented at conferences, publication in refereed journals, national workshop/symposia, and specialty conferences. These included the American Society of Agricultural and Biological Engineers, the Soil and Water Conservation Society, and Encyclopedia of Agriculture, Food, and Biological Engineering. Information was also disseminated in six undergraduate and four graduate courses. Co-mentored five students in storm water BMP projects. Work with a visiting scholar from China resulted in completion of a water droplet ballistics model for determining uniformity of various sprinkler application patterns under windy conditions for moving sprinkler systems. A technique was developed for irrigation scheduling using infrared thermometers in humid regions. Temperature thresholds were also developed for three different agronomic crops. The use of infrared thermometers (IR) to measure canopy temperatures for irrigation scheduling has been successfully applied in arid environments. Functionality of this technique in humid areas has been limited due to the presence of low vapor pressure deficits (VPD) and intermittent cloud cover. Research evaluated an alternate scheduling method for humid environments based on comparing measured canopy temperature with calculated canopy temperature of a well-watered crop. Irrigation was applied when the measured canopy temperature was greater than the predicted canopy temperature for more than three consecutive hours on two consecutive days. This method was evaluated against well-watered, semi-stressed, and dryland treatments of corn, soybean, and cotton on the basis of yield, irrigation amount, and irrigation water use efficiency (IWUE). Canopy temperature was under-predicted when the VPD was greater than 2 kPa. Limiting data to conditions when the solar radiation was greater than 200 W m-2 and the Richardson number was less than 0.2 resulted in very good prediction of canopy temperatures for cotton and soybean, particularly in the later growing period, but corn temperatures were consistently under-predicted. Although soybean and cotton yields were not significantly different across treatments, IWUE was improved for corn and cotton by use of this technique. Corn yield was greater for the well-watered crop, but the IR method resulted in 85 percent of the maximum yield while requiring less than 50 of the irrigation water. Results from this study suggest that the threshold temperature may be up to 1°C greater for corn and soybean and up to 0.5°C greater for cotton for humid compared to arid environments. This method shows potential as a tool for irrigation scheduling in humid environments. Anionic Polyacrylamide (PAM) at application rates of 0, 20, and 40 kg/ha were evaluated on a silt loam soil for reducing time to runoff (ROt), cumulative runoff (ROc), and cumulative sediment loss (SLc) for bed slopes of 10%, 20%, and 40%. Test beds were 0.3 x 0.3 x 0.15 m. Simulated rainfall was applied at 61 mm/h for 1 hr. Differences in ROt and SLc for all slopes and PAM rates were highly significant, as were all 2-way interactions. Applications of 20 and 40 kg/ha PAM significantly increased (ROt) compared to no PAM at slopes of 20% and 40% but not at 10%. Overall, slope was not a significant factor in reducing ROc. A greater rate of PAM (40 kg/ha) had less SLc than a lower rate (20 kg/ha) at slopes of 20% and 40%. Reduction in SLc was 72% greater at 40 kg/ha PAM compared to no PAM at 40% slope.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2011
Citation:
Bockhold, D.L., A.L. Thompson, K.A. Sudduth, and J.C. Henggeler. 2011. Irrigation scheduling based on crop canopy temperature for humid environments. Trans. ASABE Vol 54(6):2021-2028.
- Type:
Books
Status:
Published
Year Published:
2011
Citation:
Thompson, A.L. 2011. Drip Irrigation. Encyclopedia of Agric., Food, and Biological Engr.: 2nd Ed.
- Type:
Journal Articles
Status:
Published
Year Published:
2011
Citation:
Lee, S.S., C.J. Gantzer, A.L. Thompson, and S.H. Anderson. 2011. Polyacrylamide efficacy for reducing soil erosion and runoff as influenced by slope. J. Soil Water Conserv. Vol 66(3):172-177.
- Type:
Journal Articles
Status:
Published
Year Published:
2011
Citation:
Martin, D.L., W.L. Kranz, A.L. Thompson, H. Liang. 2011. Selecting sprinkler packages for center pivots. Trans. ASABE
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Progress 10/01/09 to 09/30/10
Outputs
Target Audience:
Nothing Reported
Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided? Please see above. How have the results been disseminated to communities of interest? Please see products for details about conference presentations and journal articles published to disseminate results. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
Results and output from research collected and reported during the period for this project included technical papers presented at conferences, publication in refereed journals, national workshop/symposia, and specialty conferences. These included the American Society of Agricultural and Biological Engineers, Soil and Water Conservation Society, National Irrigation Symposium, and the Irrigation Association. Information was also disseminated in six undergraduate and four graduate courses. An online terrace web interface model, TERLOC, was modified for use in laying out constant grade and parallel terraces. A field day demonstration was given for NRCS and SWCD personnel involved in terrace layout and design. A spreadsheet program was developed to make direct comparison based on breakeven cost analysis for transition between traditional row crop and switchgrass biomass production. Computer model to automatically determine sprinkler water droplet size distribution for various sprinklers operating on a center pivot under wind conditions was further refined under collaborative research with visiting scholar from China. A variable rate irrigation project was initiated to evaluate rice production using center pivot systems. Mentored two graduate students in the development of a science training activity for high school students considering a college engineering degree. An online web tool for terrace layout was further improved, and field day demonstration provided to engineers and scientist in local and state soil and water resource professions. Refinements were made to the TERLOC a terrace layout computer program to improve accuracy and ease of use application as an online web tool. It is estimated that this tool has potential to reduce infield time for development of terrace layouts while providing the landowner, contractor, and/or NRCS specialist with numerous terracing options. The program was improved to allow multiple key-terraces in a single field, use of variable spacing between terraces to meet soil loss limits, verify that terraces maintain adequate slope for drainage, and include provision for underground outlet design. Terrace layouts from TERLOC were compared to traditional methods used by NRCS for five different fields with varying shape and slope complexity. Terrace placement and spacing were very similar between the two methods, with most differences found in the inclusion or lack thereof for an additional terrace. Occasionally the upper terrace placed using the TERLOC program was closer or further from the ridgeline than the NRCS selection, which resulted in a different number of total terraces between the two methods. Overall terrace length for a field was typically within 20% of each other, the difference often the result of TERLOC having one more or one fewer terrace. Fields with flatter slopes were more easily accommodated than fields with steeper slopes. A simulation study evaluated the effects of variations in landscape position on runoff and dissolved atrazine utilizing the farm and field-scale APEX model for Goodwater Creek a 7250 ha agricultural watershed in north-central Missouri. The APEX model reasonably simulated runoff and dissolved atrazine concentrations (coefficient of determination ranging from 0.46 to 0.94 and from 0.45 to 0.86 for calibration and validation, respectively). The calibrated model was used to simulate variable sequencing of landscape positions and associated soil properties as well as variable lengths of landscape positions. Simulated results indicated that runoff and atrazine load increased when backslope length increased while keeping steepness constant. Maximum simulated runoff among different sequences of landscape positions occurred when backslope position was adjacent to the outlet. Landscape geometry, depth to claypan, and hydraulic conductivity were the critical characteristics separating the summit, backslope, and toeslope positions. Results are intended to help managers in placement selection of conservation practices on sensitive landscapes to improve water quality. Rainfall was applied using a gravity-fed rain simulator at rates of 64, 96, and 128 mm/h from heights of 13.8 (representing high kinetic energy, KE) and 0.8 m (low KE). PAM was less effective at increasing time to runoff (ROt) as rain rate increased. Benefits of reduced cumulative runoff (ROc) and cumulative sediment detachment (Dc) with PAM were always greater for low KE than for high KE at a given rainfall intensity. Results showed that PAM alone has a limited effect for maintaining infiltration rates over time. The greatest benefit of PAM was in significantly reduced Dc when applying 40 kg/ha compared to 20 kg/ha under high KE rain, and both PAM rates had significantly reduced Dc compared to no PAM. Under low KE rain, 20 kg/ha PAM significantly reduced Dc compared to no PAM, but Dc was not significantly different between 20 and 40 kg/ha PAM. It is likely that regions experiencing fewer intense convective storms would have greater benefit from higher PAM application rates.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2010
Citation:
Mattingly, C.M., A.L. Thompson, and C.J. Gantzer. 2010. Polyacrylamide influence on runoff and sediment detachment from a silt loam soil. Trans. ASABE, Vol 53(1):31-38.
- Type:
Journal Articles
Status:
Published
Year Published:
2010
Citation:
Lee, S.S., C.J. Gantzer, A.L. Thompson, and S.H. Anderson. 2010. Polyacrylamide and gypsum amendments for erosion and runoff control on two dissimilar soils. J. Soil Water Conserv. 65(5):233-242.
- Type:
Journal Articles
Status:
Published
Year Published:
2010
Citation:
Mudgal, A., C. Baffaut, S.H. Anderson, E.J. Sadler, and A.L. Thompson. 2010. APEX Model assessment of variable landscapes on runoff and dissolved herbicides. Trans. of ASABE, Vol 53(4):1047-1058.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2010
Citation:
Martin, D.L., W.L. Kranz, A.L. Thompson, and H. Liang. 2010. Selecting sprinkler packages for center pivots. 5th National Decennial Irrigation Conf., Pap. No. IRR10-9282., Dec 2010, Phoenix, AZ.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2010
Citation:
Thompson, A.L. K.A. Sudduth, J.C. Henggeler, E.D. Vories, A.D. Rackers. 2010. Variable rate irrigation management for humid climates using a conventional center pivot system. 5th National Decennial Irrigation Conf., Pap. No. IRR10-9849., Dec 2010, Phoenix, AZ.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2010
Citation:
Landers, G.W., A.L. Thompson, N.R. Kitchen. 2010. Managing claypan soils: annual grain crops vs. perennial switchgrass. SWCS 65th Annual International Conf., Abstract. St Louis, MO.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2010
Citation:
Landers, G.W. A.L. Thompson, N.R. Kitchen. R.E. Massey, D.E. Brune. 2010. Biofuel feedstock from claypan soils for annual grain and perennial switchgrass. SWCS Specialty Workshop, Sustainable Feedstocks for Advanced Biofuels, Abstract. Atlanta, GA. Sep., 2010
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2010
Citation:
Bay, M.K., A.L. Thompson, K.A. Sudduth, C.J. Gantzer. 2010. Staking terraces online: a terrace layout program. SWCS 65th Annual International Conf., Abstract. St Louis, MO.
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Progress 10/01/08 to 09/30/09
Outputs
Target Audience:
Nothing Reported
Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?
Nothing Reported
How have the results been disseminated to communities of interest? Results were presented at scientific conferences, shared with graduate students and in journal articles. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
Results and output from research collected and reported during the period for this project included technical papers presented at conferences, publication in refereed journals, national workshop/symposia, and specialty conferences. These included the American Society of Agricultural and Biological Engineers and the Soil and Water Conservation Society. Information was also disseminated in five undergraduate and three graduate courses. Refinements were made to improve the ease of use and performance of an online web-interface terrace layout program. Cover-story article on this tool appeared in the ASABE professional society RESOURCE magazine, September issue. Invited presentations were given at area soil water conservation districts, University of Missouri (MU) Technology Conference, and MU agricultural engineering workshop. Invited presentations on effective methods to control urban stormwater runoff were given at MU stormwater management workshop and a county extension program. Computer model to automatically determine sprinkler water droplet size distribution for various sprinklers operating on a center pivot under wind conditions was initiated with collaborative research with visiting scholar from China. Served as host for three visiting South Korean scholars for training in storm water management. Advisement included five graduate students in engineering and natural resources. Traditional layout of terraces can take up to 50 percent of the technical assistance time provided for terrace design according to the USDA NRCS. Refinements made to a terrace layout computer program improved the accuracy and ease of use for using the program as an online web tool. It is estimated that this tool has potential to reduce infield time for development of terrace layouts while providing the landowner, contractor, and/or NRCS specialist with numerous terracing options. This is also intended to make better use of cost-share dollars through MDNR and NRCS. Polyacrylamide (PAM) is an emerging conservation practice, but application guidelines for soils with varying texture and pH are not well developed. Surface application of PAM was evaluated on acid and neutral soils as well as high- and low-clay content soils at PAM application rates of zero, 20, and 40 kg/ha. Gypsum was evaluated at 5 Mg/ha with no PAM and with 20 kg/ha PAM. Simulated rainfall at 61 mm/hr was applied to soil beds 0.3 m wide x 0.3 m long x 0.15 m tall. Differences in time to runoff (ROt), cumulative runoff (ROc), and cumulative sediment loss (SLc) were highly significant for all soils, as were their two-way interactions. Combination of 20 kg/ha PAM and 5 Mg/ha gypsum was the best overall erosion control, with average ROt significantly delayed by 38 percent, ROc reduced by 25 percent, and SLc loss reduced by 32 percent compared to no amendments. This same combination applied to high-clay acid soils reduced ROt by 41 percent, ROc by 45 percent, and SLc by 68 percent compared to no amendments. Use of 40 kg/ha PAM was not effective in reducing ROc on high-clay soil with high organic matter, but significantly reduced SLc for high-clay acid soil. It was significantly more effective than 20 kg/ha on acid soil for either low- or high-clay content. Runoff and sediment loss were evaluated for a silt loam soil when 0, 20, and 40 kg/ha PAM were surface applied prior to rainfall. Irrigation scheduling is known to improve water use efficiency (WUE), but many producers find traditional scheduling methods time consuming or difficult to apply, resulting in a lack of implementation. This becomes even more critical on fields that have various soil textures distributed throughout the area. Variable rate irrigation (VRI) shows promise to improve water management for such conditions, but cost of new or retro-fit systems can be prohibitive. Standard center pivot panels with the capability of variable speed control show promise for use in improving WUE without the need of purchasing an entire VRI system. Corn production for center pivot irrigation in the humid mid-south was evaluated using such a standard control center pivot on soils with sand texture ranging from less than 10 to greater than 90 percent sand content. Irrigation depths were varied from 8 to 46 mm per set with yields averaged across four sand classes. Results indicate that the greatest yield was achieved at 15 mm irrigation water per set averaged across all sand classes, although not significantly different from yields for 8 mm per set. Yields on average were lower as sand content increased. Yields were greater for all irrigation treatments compared to dryland production. The greatest irrigated WUE was also found for the 15 mm treatment.
Publications
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2009
Citation:
Golden, M.K., A.L. Thompson, C.J. Gantzer, K.A., Sudduth, K.A. Mayhan, R. Purcell. 2009. Terrace layout using a computer assisted system. SWCS Annual International Conf., Abstract. Dearborn, MI.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2009
Citation:
Lee, S., C.J. Gantzer, A.L. Thompson, S.H. Anderson. 2009. Influence of texture and pH for polyacrylamide control of erosion and runoff. SWCS Annual International Conf., Abstract. Dearborn, MI.
- Type:
Journal Articles
Status:
Published
Year Published:
2009
Citation:
Thompson, A.L. 2009. On the internet: automated terrace layout. Resource Magazine ASABE Vol 16(6):4-5.
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Progress 10/01/07 to 09/30/08
Outputs
Target Audience:
Nothing Reported
Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?
Nothing Reported
How have the results been disseminated to communities of interest? Project results have been presented at professional conferences as well as shared in classroom settings and with graduate students. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
Results and output from research collected and reported during the period for this project included technical papers presented at conferences, publication in refereed journals, national workshop/symposia, and specialty conferences. These included the American Society of Agricultural and Biological Engineers, the Soil Science Society of America, and the Soil and Water Conservation Society. Information was also disseminated in six undergraduate and four graduate courses. Evaluation of high resolution X-ray computed tomography (HRCT) successfully provided quantitative measurements of changes in soil porosity of intact soil surface seals, demonstrating that such methods are useful in studying effects of soil and soil amendments. It is noted that the WEPP model for hillslope analysis did not adequately simulate slope length reduction effects from vegetative grass hedges, and future work should be directed to address this need. Developed a protocol based on the APEX model to help delineate proper placement selection of BMPs to improve water quality and conservation management. Rainfall on bare soils typically results in the formation of high bulk density soil surface seals, reducing infiltration rate with increasing surface runoff. The rate of seal formation is a function soil characteristics and raindrop energy. Traditional methods of evaluating surface seals required the time consuming method of thin-section analysis for 2-dimensional evaluation. This research evaluated the use of high-resolution X-ray computed tomography (HRCT) to acquire non-destructive 3-dimensional (3D) images. Images for a silt loam soil successfully identified pore sizes less than 15 microns within developing surface seals. Rainfall rate was 55-mm/h with soils samples taken at 7.5, 15, 30, and 60 minute durations. Analysis included pore size distribution and cumulative porosity from 0 to 1 mm and 1 to 2mm depths for Polyacrylamide (PAM, 20 kg/ha) treated and untreated soil. The difference in cumulative porosity between PAM-treated and untreated soil significantly increased with rainfall duration. Pore frequency was significantly reduced in pore sizes from 0.0001 to 0.00001 cubic mm. After 60 min of rainfall the cumulative porosity was reduced 39 times more for the untreated vs. the PAM treated soil. It is feasible to relate HRCT measure porosity to quantify soil hydraulic conductivity. The HRCT image analysis procedure should be useful for quantifying soil surface seals for various soils, and for assessing practices to reduce surface seal formation. Grass hedges planted at regular intervals across the landscape slope have been observed to reduce runoff and sediment loss. The ability of the WEPP model to simulate the effects of a grass hedge system were evaluated on the bases of sediment trapping (TE), bench terracing (BT), and variable effective soil hydraulic conductivity (HC) on simulated hillslope runoff and sediment yield. Additionally WEPP was used to model the effects of measured effective hydraulic conductivity (Keff) from a grass hedge management system by comparing predicted runoff and sediment yield values to those measured in a small watershed over an 11-yr period. Field measurements were taken on a 6.6 ha watershed in the deep loess hills of southwestern Iowa. Narrow grass hedges (switchgrass) were planted at 15.4 m intervals. The WEPP model simulated 9 percent greater reductions in runoff and 58 percent greater sediment yield from BT compared to TE and HC effects. Combination of all three effects gave the greatest reductions in runoff (22 percent) and sediment yield (79 percent) compared to individual or any two combined effects. The WEPP model did not adequately simulate slope length reduction effects from the grass hedges. Runoff and sediment yield were comparable to observed date when measured Keff values for grass hedge, row crop, and channel areas were used as inputs.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2008
Citation:
Rachman, A., S.H. Anderson, E.E. Alberts, A.L. Thompson, and C.J. Gantzer. 2008. Predicting runoff and sediment yield from a stiff-stemmed grass hedge system for a small watershed. Trans. of ASABE, Vol 51(2):1-8.
- Type:
Journal Articles
Status:
Published
Year Published:
2008
Citation:
Lee, S., C.J. Gantzer, A.L. Thompson, S.H. Anderson, and R.A. Kecham. 2008. Soil surface-seal characterization using analysis of high resolution computed tomography. SSSAJ: Vol 72(5):1478-1485.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2008
Citation:
Gantzer, C.J., A.L. Thompson, B.D. Mayhan, R. Purcell, and S.H. Anderson. 2008. Computer-Assisted Terrace Design for Improved Farmability. SWCS Annual International Conf., Abstract. Tucson, AZ.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2008
Citation:
Mudgal, A., C. Baffaut, S.H. Anderson, E.J. Sadler, A.L. Thompson. 2008. APEX model assessment of variable landscapes on runoff and dissolved herbicides. ASABE Annual Mtg., Pap. No. 08-4489, Providence, RI.
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Progress 03/01/07 to 09/30/07
Outputs
Target Audience:
Nothing Reported
Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?
Nothing Reported
How have the results been disseminated to communities of interest? Project results were shared via journal articles and conference presentations. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
Results and output from research collected and reported during the period for this project included technical papers presented at conferences, publication in refereed journals, national workshop/symposia, and specialty conferences. These included the American Society of Agricultural and Biological Engineers, and the Soil and Water Conservation Society. Information was also disseminated in five undergraduate and five graduate courses. Invited presentations were given at the University of Missouri (MU) Urban Erosion and Water Management workshops (April) and Runge Center (video taped; Sept). Engineering Consulting for the MU Center for Agricultural Research and Environmental Sciences (CARES) on storm water flood plain evaluation for 100-yr events in Missouri, SEMA and FEMA. A watershed model for atrazine concentration in runoff was developed using the Soil Water Assessment Tool and calibrated for water flow. Soil splash and detachment of soil lost to sheet and interrill erosion during rainfall is a function of the droplet kinetic energy (KE). Rainfall consists of a spectrum of drop sizes, and total KE is dependent upon the distribution of those sizes. Field research is both expensive and problematic in that frequency, duration, and areal distribution of rainfall is highly variable, therefore simulated rainfall has often been used to study basic principles of soil erosion. This research has historically used one of three methods to form raindrops via simulators: hanging yarn, gravity tubing tips, and sprinkler simulators. However, each method has shortcomings when attempting to replicate rainfall energy and drop size distribution of natural rainfall. Results from this research indicate that simulated rainfall using gravity, tube-type simulators can replicate natural rainfall under low wind speeds and similar rainfall rates. Use of a properly located splash screen beneath the dripper beds can fine tune droplet size distributions (DSD) to be similar to natural rainfall. Notable issues with simulated rainfall include limitations on maximum drop size diameter, absence of turbulence, and lack of rapid rainfall rate variability, all which are present in natural rainfall but difficult to replicate with gravity-fed simulators. Previous studies reported in the literature indicate that up to one-fourth of the total KE from rain storms results from enhanced wind driven rainfall. Estimation of KE from storms studied here accounted for nearly one-half of the total KE. This is likely because nearly half of the convective storm rainfall events observed here had stronger winds than those rainfall events previously reported where these data were collected. A gamma curve has typically been used to numerically represent the DSD having a mu-shape factor equal to zero (exponential). Recent literature indicates that a non-zero factor more accurately represents high energy, convective rainfall while the exponential curve best represents non-convective rainfall. However, DSDs observed in convective storms in this research more closely resemble an exponential curve with mu-values near zero. Atrazine concentrations at the outlet of Goodwater Creek watershed in Northeast, MO decreased from the period of 1993 to 2003. Statistical analysis shows that temperature, which can be directly attributed to earlier planting dates, is one of several important variables that explain the decreased concentrations. Use of vegetative waterways had a significant impact on reducing atrazine concentrations in runoff compared to other BMPs.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2007
Citation:
J. Jones, A.L. Thompson, C.N. Seong, J.S.Jung, and H. Yang. 2006. Monsoon influences on the limnoogy of Juam Lake, South Korea. Verh. Internat. Verein., Limnol. Vol (29):1215-1222.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2007
Citation:
Baffaut, C., A.R. Bockhold, A.L. Thompson, E.J. Sadler, R.N. Lerch. 2007. SWAT Assessment of management practices on atrazine loss in Goodwater Creek experimental watershed. SWCS Annual International Conf., Abstract. Tampa, FL.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2007
Citation:
Gilmore, W.T., A.L. Thompson. 2007. Comparison of rainfall energy and soil erosion parameters from a rainfall simulator and natural rainfall. ASABE Annual International Mtg., Pap. No. 07-2230, Minneapolis, MN.
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