Progress 10/01/05 to 09/30/10
Outputs
OUTPUTS: Stand establishment uniformity in maize is an intuitively important component for achieving the maximum yield potential in a given field in a given year. Field-scale trials were conducted over nine site-years throughout Indiana from 2004-2006 to determine whether varying levels of plant spacing variability (PSV) influence maize grain yield in large-scale field plots planted to a single, aggressive, seeding rate. Over the nine site-years, grain yields varied significantly among the five PSV treatments, with the greatest yields occurring with the more uniformly spaced treatments and lowest yields occurring with the least uniformly spaced treatments. Significant negative linear relationships were identified between maize grain yield and actual (measured) standard deviation of plant spacing at that accounted for approximately 66% of the variability observed among treatment means for grain yield. The mean rate of yield loss per cm of SD was 0.3% of optimum yield, for total yield losses as great as 6.4% due to uneven plant-to-plant spacing. Results from this project emphasize the important role that uniform seeding of maize has on optimizing eventual grain yield. Better maintenance, repairs, and operation of the planter by the grower can easily correct problems of uneven plant spacing and, thus, improve yields of maize at minimal cost. Field-scale research trials were conducted 2006 - 2010 with the objective of identifying average and geography-specific nitrogen fertilizer rates for maize that best balance optimum yield and optimum profitability. Twelve trials were established at seven Purdue research farms (seven in a maize-soybean rotation, five in a maize-maize rotation) throughout Indiana each year plus approximately 82 on-farm sites (primarily maize-soybean rotations). Results indicated a wide range of values for agronomic optimum N rates over more than 140 site-years. The mean agronomic optimum N rate for all rotation maize trials was 216 kg/ha. When estimates of soil-supplied N were added to rates of applied fertilizer N, the amount of total N required to achieve optimum agronomic yield was equal to approximately 303 kg/ha and was very consistent across all of the trials. This result suggests that efforts to estimate soil N prior to fertilization (e.g., soil sampling, optical crop sensors) would be beneficial in helping fine-tune the required rate of fertilizer N for an individual field. Agronomically optimum N rates for maize following maize averaged 45 kg/ha N higher than maize following soybean, but yielded approximately 1900 kg/ha less. The 2009 Nitrogen Use Efficiency Conference was organized and held at Purdue. Results of our research were presented at demonstrations, field days, workshops and trainings. In total about 50 presentations were made to approximately 5,000 individuals. Written materials were distributed at the presentations and also available on the Web. A summary of the field aspects of this research was downloaded more than 4,000 times. Results from these studies appeared in at least 30 popular press articles in print and electronically. PARTICIPANTS: Collaborators and partners: James Camberato (Purdue Univ), Brad Joern (Purdue Univ), Eric Miller (Purdue graduate student), Dan Emmert (Purdue graduate student), Norm Larson (Case-IH), Jacky Payne (Case-IH), Eric White (Case-IH), Jim Beaty (Purdue research farms), Jon Leuck (Purdue research farms), Phil Walker (Purdue research farms), Jeff Boyer (Purdue research farms), Don Biehle (Purdue research farms), Dennis Nowaskie (Purdue research farms), Jay Young (Purdue research farms) TARGET AUDIENCES: Target audiences: Indiana corn growers, Certified Crop Advisers, local Purdue Extension ANR Educators, independent crop consultants, Indiana seed, chemical, and fertilizer industries. Efforts: Extension publications (print and online), Extension programs (county, regional, state, multi-state). PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
Results from the research on the effects of uneven plant-to-plant spacing in corn have helped Indiana corn growers improve yields and profitability as a result of their efforts to minimize uneven plant spacing through more frequent and comprehensive planter maintenance and adjustments during operation of planters. Typical levels of uneven plant spacing in corn fields today is less than those first surveyed in the 1990's. Results from the research on corn yield response to application rates of nitrogen fertilizer have helped Indiana corn growers to either lower their usual application rates without lowering yield or increase yield by increasing their usual rates of applied nitrogen fertilizer.
Publications
- Emmert, D., R.L. Nielsen, B. Joern, and J. Camberato. 2007. Predicting relative yield of corn with an active sensor in Indiana. In Agronomy abstracts, ASA,SSSA, CSA, Madison, WI.
- Nielsen , RL (Bob), Eric White, Jacky Payne, and Norman Larson. 2008. Planting Field-Scale Research Plots with the Aid of GPS-Enabled Assisted Steering. Agron. J. 100:777-778.
- Camberato, Jim, Bob Nielsen, Brad Joern, and Eric Miller. 2010. Nitrogen Management Update for Indiana. Purdue University Cooperative Extension. [online] http://www.agry.purdue.edu/ext/corn/news/timeless/NitrogenMgmt.pdf.
- Miller, Eric, Jim Camberato, & RL (Bob) Nielsen. 2010. Variability of Maize Canopy Reflectance within Field-Length Strips Fertilized with Low to High Rates of Nitrogen. Agronomy Abstracts. Amer. Soc. Agry. [online] http://a-c-s.confex.com/crops/2010am/webprogram/Paper59378.html.
- Miller, Eric, Jim Camberato, & RL (Bob) Nielsen. 2010. Nitrogen fertilizer effects on corn grain nutrient composition. Agronomy Abstracts. Amer. Soc. Agry. [online]. http://a-c-s.confex.com/crops/2010am/webprogram/Paper59402.html.
- Johnson, W.G, Ott, E.J., Gibson, K.D., Nielsen, R.L., Bauman, T.T. 2007. Influence of nitrogen application timing on low density giant ragweed (Ambrosia trifida) interference in corn. Weed Tech. 21(3) 763-767.
- Camberato, Jim, Bob Nielsen, Dan Emmert, Brad Joern. 2007. Purdue Nitrogen Rate Trials. Proceedings of the 2007 Indiana CCA Conference. Purdue Extension. [CD].
- Nielsen, RL (Bob). 2006. N Loss Mechanisms and Nitrogen Use Efficiency. Proceedings of 2006 FAR Maize Conference, Hamilton, NZ. Foundation for Arable Research, Lincoln, NZ.
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Progress 10/01/08 to 09/30/09
Outputs
OUTPUTS: Field-scale research trials, begun in 2006, were continued in 2009 with the objectives of a) identifying average and geography-specific nitrogen fertilizer rates for corn that best balance optimum yield and optimum profitability and b) evaluating the capability of optical crop sensors for estimating nitrogen (N) sufficiency status in corn. Twelve trials were established at seven Purdue research farms (seven in a corn-soybean rotation, five in a corn-corn rotation) throughout Indiana plus approximately five on-farm sites (primarily corn-soybean rotations). Trial protocols included the application of five to six N rate treatments, ranging from 0 to over 200 lbs/ac actual N. Data collected included grain yield, grain moisture content, soil nitrate content early in the season, stalk nitrate content after physiological maturity, ear leaf N content at silking, yield components, optical sensor measurements at approximately growth stage V11, and optical sensor measurements at silking. PARTICIPANTS: The 2009 Nitrogen Use Efficiency Conference was held at Purdue and organized by Camberato and RL Nielsen. Results of our research were presented at demonstrations, field days, workshops and trainings. In total about 30 presentations were made to approximately 2,100 individuals. Written materials were distributed at the presentations and also available on the web. A summary of the field aspects of this research was downloaded more than 2,000 times. Results from these studies appeared in at least 15 popular press articles in print and electronically. TARGET AUDIENCES: Farmers, crop consultants, county Extension educators, industry agronomists, certified crop advisors PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Results from 2009 are still being tabulated, but results from the previous two years indicated a wide range of values for agronomic optimum N rates over more than 100 site-years. The mean agronomic optimum N rate for all trials conducted in 2006-2008 was 177 lbs/ac, but ranged from 100 to 255 lbs/ac among sites. When estimates of soil-supplied N were added to rates of applied fertilizer N, the amount of total N required to achieve optimum agronomic yield was equal to approximately 270 lbs/ac and was very consistent across all of the trials. This result suggests that efforts to estimate soil N prior to fertilization (e.g., soil sampling, optical crop sensors) would be beneficial in helping fine-tune the required rate of fertilizer N for an individual field. At sites in 2007-2008 where crop rotations were established in adjacent fields, corn following corn required 37 more lbs/ac N to achieve optimum agronomic yield than corn following soybean, but yielded 21 bu/ac less. The 2009 Nitrogen Use Efficiency Conference was organized and held at Purdue. Results of our research were presented at demonstrations, field days, workshops and trainings. In total about 30 presentations were made to approximately 2,100 individuals. Written materials were distributed at the presentations and also available on the web. A summary of the field aspects of this research was downloaded more than 2,000 times. Results from these studies appeared in at least 15 popular press articles in print and electronically.
Publications
- Camberato, J., R. Nielsen, and B. Joern. Dec. 2008. Nitrogen Management Update for Indiana. http://www.agry.purdue.edu/ext/corn/news/timeless/NitrogenMgmt.pdf.
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Progress 10/01/07 to 09/30/08
Outputs
OUTPUTS: Field-scale research trials, begun in 2006, were continued in 2008 with the objectives of a) identifying average and geography-specific nitrogen fertilizer rates for corn that best balance optimum yield and optimum profitability and b) evaluating the capability of optical crop sensors for estimating nitrogen (N) sufficiency status in corn. Twelve trials were established at seven Purdue research farms (seven in a corn-soybean rotation, five in a corn-corn rotation) throughout Indiana plus approximately twelve on-farm sites (primarily corn-soybean rotations). Trial protocols included the application of five to six N rate treatments, ranging from 0 to over 200 lbs/ac actual N. Data collected included grain yield, grain moisture content, soil nitrate content early in the season, stalk nitrate content after physiological maturity, ear leaf N content at silking, yield components, optical sensor measurements at approximately growth stage V11, and optical sensor measurements at silking. PARTICIPANTS: Principal investigators on this project are James Camberato and R.L. (Bob) Nielsen (both Purdue Agronomy). Brad Joern (Purdue Agronomy) is a collaborator on the project. TARGET AUDIENCES: Target audiences for this project include corn growers, county Extension educators, industry agronomists, fertilizer retailers, and independent crop consultants. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Results from 2008 are still being tabulated, but results from the previous two years indicated a wide range of values for agronomic optimum N rates over nearly 80 site-years. The mean agronomic optimum N rate for all trials conducted in 2006-2007 was 177 lbs/ac, but ranged from 100 to 255 lbs/ac among sites. When estimates of soil-supplied N were added to rates of applied fertilizer N, the amount of total N required to achieve optimum agronomic yield was equal to approximately 270 lbs/ac and was very consistent across all of the trials. This result suggests that efforts to estimate soil N prior to fertilization (e.g., soil sampling, optical crop sensors) would be beneficial in helping fine-tune the required rate of fertilizer N for an individual field. At sites in 2007-2008 where crop rotations were established in adjacent fields, corn following corn required 37 more lbs/ac N to achieve optimum agronomic yield than corn following soybean, but yielded 21 bu/ac less.
Publications
- Camberato, Jim, Bob Nielsen, Dan Emmert, and Brad Joern. 2007. Nitrogen Management Update for Indiana. Purdue University. [on-line] Available at http://www.kingcorn.org/news/articles.07/NMgmtUpdate-1206.pdf (URL accessed 11/7/08).
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Progress 10/01/06 to 09/30/07
Outputs
OUTPUTS: Stand establishment uniformity in maize is an intuitively important component for achieving the maximum yield potential in a given field in a given year. Uneven stands may be described in terms of variability for plant-to-plant spacing within the row, time of seedling emergence, and/or eventual growth and development. With the collaborative assistance of Case IH engineers and agronomists, five sets of seed discs for use with a Case IH 1200 ASM air planter were custom-engineered with distinctive patterns of seed cell positions that would create predictable planting patterns of crowded seeds and gaps. Field-scale trials were conducted over nine site-years throughout Indiana from 2004-2006 to a) verify whether repeatable levels of plant spacing variability (PSV) in large-scale field plots could be reliably created using custom-manufactured seed discs and a commercial-sized air planter, and b) determine whether varying levels of plant spacing variability influence maize grain
yield in large-scale field plots planted to a single, aggressive, seeding rate.
PARTICIPANTS: Partner Organizations: CaseIH (in-kind contribution of seed disc engineering, planter, tractor, and transportation), Diener Seeds (in-kind contribution of seed). Collaborators and contacts: CaseIH: Monte Weller, Eric White, Jacky Payne, and Norman Larson. Purdue Ag Centers: Jay Young, Jon Leuck, Phil Walker, Jeff Boyer, and Don Biehle.
TARGET AUDIENCES: Corn growers, crop consultants, county Extension educators, industry agronomists, other certified crop advisors
Impacts
Results indicated that the custom-engineered planter seed discs did what they were designed to do; create repeatable treatment levels of plant spacing variability. The actual (measured) standard deviations of plant spacing for each targeted PSV treatment level (standard deviation (SD) of plant spacing ranging from 0 to 20 cm) were very close to what was predicted at the onset of the trial. Over the nine site-years, grain yields varied significantly among the five PSV treatments, with the greatest yields occurring with the more uniformly spaced treatments and lowest yields occurring with the least uniformly spaced treatments. Significant negative linear relationships were identified between maize grain yield and actual (measured) standard deviation of plant spacing at that accounted for approximately 66% of the variability observed among treatment means for grain yield. The mean rate of yield loss per cm of SD was 0.3% of optimum yield, for total yield losses as great
as 6.4% due to uneven plant-to-plant spacing. Results from this project emphasize the important role that uniform seeding of maize has on optimizing eventual grain yield. Uniform seeding is predominately influenced by the condition and operation of the planter. Better maintenance, repairs, and operation of the planter by the grower can easily correct problems of uneven plant spacing and, thus, improve yields of maize at minimal cost.
Publications
- No publications reported this period
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Progress 10/01/05 to 09/30/06
Outputs
Stand establishment uniformity in maize is an intuitively important component for achieving the maximum yield potential in a given field in a given year. Uneven stands may be described in terms of plant-to-plant variability for spacing within the row, time of seedling emergence, and/or eventual growth and development. With the collaborative assistance of Case IH engineers and agronomists, five sets of seed discs for use with a Case IH 1200 ASM air planter were custom-engineered with distinctive patterns of seed cell positions that would create predictable planting patterns of crowded seeds and gaps. Field-scale trials were established at five locations throughout Indiana in 2006 to 1) verify whether we could reliably create repeatable levels of plant spacing variability (PSV) in large-scale field plots using custom-manufactured seed discs and a commercial-sized air planter, and 2) determine whether varying levels of plant spacing variability influence maize grain
yield in large-scale field plots planted to a single, aggressive, seeding rate. Results from the 2006 trials are not yet analyzed, but results from 2004-2005 field trials indicated that the custom-engineered planter seed discs did what they were designed to do; create repeatable treatment levels of plant spacing variability. The actual (measured) standard deviations of plant spacing for each targeted PSV treatment level were very close to what was predicted at the onset of the trial. Results from the 2004-2005 trials also indicated that grain yields varied significantly among the five PSV treatments, with the greatest yields occurring with the more uniformly spaced treatments and lowest yields occurring with the least uniformly spaced treatments. Significant negative linear relationships were identified between maize grain yield and actual (measured) standard deviation of plant spacing at 5 of the 6 locations in 2004-2005 that accounted for nearly 80-97% of the variability observed
among treatment means for grain yield. The mean rate of yield loss per cm of SD (49.4 kg ha-1) was similar to that which I observed in my original studies over 10 years ago (61.8 kg ha-1).
Impacts
Results to date from this project emphasize the important role that uniform seeding of maize has on optimizing eventual grain yield. Uniform seeding is predominately influenced by the condition and operation of the planter. Better maintenance, repairs, and operation of the planter by the grower can easily correct problems of uneven plant spacing and, thus, improve yields of maize at minimal cost.
Publications
- No publications reported this period
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Progress 10/01/04 to 09/30/05
Outputs
Stand establishment uniformity in maize is an intuitively important component for achieving the maximum yield potential in a given field in a given year. Uneven stands may be described in terms of plant-to-plant variability for spacing within the row, time of seedling emergence, and/or eventual growth and development. With the collaborative assistance of Case IH engineers and agronomists, five sets of seed discs for use with a Case IH 1200 ASM air planter were custom-engineered with distinctive patterns of seed cell positions that would create predictable planting patterns of crowded seeds and gaps. Field-scale trials were established at five locations throughout Indiana in 2005 to 1) verify whether we could reliably create repeatable levels of plant spacing variability (PSV) in large-scale field plots using custom-manufactured seed discs and a commercial-sized air planter, and 2) determine whether varying levels of plant spacing variability influence maize grain
yield in large-scale field plots planted to a single, aggressive, seeding rate. Results from the 2005 trials are not yet analyzed, but a preliminary large-scale field research trial conducted in 2004 at a single location in northwest Indiana indicated that the custom-engineered planter seed discs did what they were designed to do; create repeatable treatment levels of plant spacing variability. The actual (measured) standard deviations of plant spacing for each targeted PSV treatment level were very close to what was predicted at the onset of the trial. Results from the 2004 trial also indicated that grain yields varied significantly among the five PSV treatments, with the greatest yields occurring with the more uniformly spaced treatments and lowest yields occurring with the least uniformly spaced treatments. A significant negative linear relationship was identified between maize grain yield and actual (measured) standard deviation of plant spacing in this trial that accounted for
nearly 97% of the variability observed among treatment means for grain yield. The rate of yield loss per cm of SD (54.3 kg ha-1) was very similar to that which I observed in my original studies over 10 years ago (61.8 kg ha-1).
Impacts
Results to date from this project emphasize the important role that uniform seeding of maize has on optimizing eventual grain yield. Uniform seeding is predominately influenced by the condition and operation of the planter. Better maintenance, repairs, and operation of the planter by the grower can easily correct problems of uneven plant spacing and, thus, improve yields of maize at minimal cost.
Publications
- No publications reported this period
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Progress 10/01/03 to 09/29/04
Outputs
A field-scale yield monitor calibration project was begun in 2002 at the Davis-Purdue Agricultural Center in eastcentral Indiana and the Northeast-Purdue Agricultural Center in northeast Indiana, expanded to the Pinney-Purdue Agricultural Center in northwest Indiana in 2003, and expanded further in 2004 to the Southeast-Purdue Agricultural Center in southeast Indiana. The 2004 studies were also expanded to include two hybrids differing for relative maturity and grain test weight potential. The objective is to document and describe the influences of the frequency or timing of yield monitor calibration on the estimates of grain flow, grain moisture content, and, ultimately, grain yield per unit area during the course of a typical harvest season. The manufacturer of the commercial yield monitor used in the study strongly encourages the entry of multiple calibration "loads" to perform the yield monitor calibration. Preliminary data suggest that the magnitude of yield
monitor estimation errors increase over the course of the harvest season if the yield monitor is calibrated only at the beginning of the season. Conversely, mid-season calibration procedures retroactively influence the accuracy of earlier-harvested grain yield estimates during the course of post-harvest processing of the data. The accuracy of grain moisture estimates by the combine moisture sensor also decreases as the harvest season progresses, which interestingly influences the estimates of wet weight grain flow by the monitor. Practical challenges to farmers relative to the yield monitor calibration process include a) availability of accurate on-farm weigh scales to verify load weight estimates by the yield monitor, b) availability of accurate portable grain moisture meters to verify grain moisture content estimates by the yield monitor, c) difficulty in representing a broad range of grain flow rates in the multiple calibration loads required for the calibration process, and d) the
time required to perform regular calibrations during the typically hectic pace of the harvest season. The consequences of inadequate yield monitor calibration primarily affect the interpretation of yield maps and subsequent decision-making based on those maps. There are few consequences in the marketplace since growers are paid on the basis of grain weight measured at the point of sale and not on the basis of yield monitor grain yield estimates.
Impacts
By identifying the effects of irregular or infrequent calibration of yield monitors on the estimation of grain yield and grain moisture content, growers will have a clearer idea of the agronomic and economic consequences of not following a purposeful calibration schedule.
Publications
- No publications reported this period
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Progress 10/01/02 to 09/30/03
Outputs
A yield monitor calibration project was begun in 2002 on 12 ha fields at the Davis-Purdue Agricultural Center in eastcentral Indiana and the Northeast-Purdue Agricultural Center in northeast Indiana, and expanded to the Pinney-Purdue Agricultural Center in northwest Indiana and the Southeast-Purdue Agricultural Center in southeast Indiana in 2003. The objective is to determine whether the frequency of yield monitor calibration influences estimated grain flow, estimated grain moisture content, and, ultimately, estimated grain yield per unit area by the technology. The project is concentrating on one of the most commonly used brands of yield monitors that requires the harvest of multiple calibration loads to perform the yield monitor calibration. Preliminary data suggest that the magnitude of yield monitor estimation errors increase over the course of the harvest season if the yield monitor is calibrated only at the beginning of the season. Practical challenges to
farmers relative to the yield monitor calibration process have been identified and include a) availability of accurate on-farm weigh scales to verify load weight estimates by the yield monitor, b) availability of accurate portable grain moisture meters to verify grain moisture content estimates by the yield monitor, c) difficulty in representing a broad range of grain flow rates in the multiple calibration loads used during the calibration process, and d) the time required to perform regular calibrations in light of the hectic pace of a typical harvest season. The consequences of inadequate yield monitor calibration primarily affect the interpretation of yield maps and subsequent decision-making based on those maps. There are few consequences in the marketplace since growers are paid on the basis of grain weight measured at the point of sale and not on the basis of yield monitor data.
Impacts
By identifying the consequences of irregular or infrequent calibration of yield monitors on the estimation of grain yield and grain moisture content, growers will have a clearer idea of the agronomic and economic consequences of not following a purposeful calibration program.
Publications
- No publications reported this period
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Progress 10/01/01 to 09/30/02
Outputs
Field research was continued with the overall objective to evaluate site-specific crop management technologies for corn (Zea mays L.) and soybean (Glycine max L.) production in the eastern U.S. Corn Belt. Two graduate students completed their M.S. research projects in 2002. The first project, conducted on 49 ha at the Davis-Purdue Agricultural Center in eastcentral Indiana, evaluated the performance of several geostatistical interpolation methods, with and without the aid of secondary information (remotely sensed imagery), at relatively intense (1 sample/0.2 ha) and sparse (1 sample/1 ha) soil sampling densities. Among four methods compared, Simple Kriging with Varying Means proved to be the best method for both sampling densities for mapping soil organic matter variability. Even at the high sampling density, the methods that make use of remotely sensed imagery showed considerably better results. The second project, conducted on three no-till 12 ha farmer fields in
westcentral and eastcentral Indiana, investigated whether the spatial pattern of soil core collection following a corn crop influences the measured values resulting from soil sample analysis for specific sample grid areas of fields. The spatial pattern of soil core collection did not affect the resulting soil test data values for soil phosphorus, pH, organic matter, or cation exchange capacity. Soil core collection patterns that included sampling from the middles of the previous corn crop rows resulted in slightly higher soil potassium values than those patterns that involved sampling only from within the old corn rows. A yield monitor calibration project was begun in 2002 on 12 ha fields at the Davis-Purdue Agricultural Center in eastcentral Indiana and the Northeast-Purdue Agricultural Center in northeast Indiana. The objective is to determine whether the frequency of yield monitor calibration influences yield estimation. Preliminary data suggest that errors in both yield and grain
moisture estimates by the yield monitor increase over the course of the harvest season if the yield monitor is only calibrated at the beginning of the season.
Impacts
Developing believeable spatial maps based on sparsely collected spatial data has always been a geostatistical challenge. The improvement in geostatistical interpolation with the aid of densely collected secondary information such as remotely sensed imagery enhances the ability to manage and use sparsely collected crop and soil management spatial data.
Publications
- Colonna, I.A. 2002. Accuracy of Spatial Estimation Methods for Site-Specific Agriculture at Different Sample Densities. M.S. Thesis, 198 pp., Department of Agronomy,Purdue Univ., W. Lafayette, IN 47907, May 2002.
- Taylor, D. 2002. The Effect of Soil Sample Collection Patterns on the Consistency of Soil Test Results. Report on M.S. Non-Thesis Special Project Agronomy Dept, Purdue Univ., W. Lafayette, IN 47907.
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Progress 10/01/00 to 09/30/01
Outputs
Data collection continued in a 49 ha field study established in 1998 at the Davis-Purdue Agricultural Center in eastcentral Indiana. The general objective of the project is to evaluate site-specific crop management technologies for corn (Zea mays L.) and soybean (Glycine max L.) production in the eastern U.S. Corn Belt. The performance of different geostatistical interpolation methods, with and without the use of secondary information, at relatively intense (1 sample/0.2 ha) and sparse (1 sample/1 ha) soil sampling densities was evaluated for mapping soil organic matter variability. Among four methods compared, Simple Kriging with Varying Means proved to be the best method for both sampling densities. Even at the high sampling density, the methods that make use of secondary information showed considerably better results. Inverse Distance Weighting and Ordinary Kriging yielded very poor and inconsistent results at low sampling densities, unacceptable for practical
applications. The use of other potential sources of secondary information like soil electrical conductivity or topography might be explored as alternatives to bare soil imagery. Some may represent better secondary information for other soil fertility or crop variables. Georeferenced grain composition samples collected on-the-go during harvest of corn and soybean in 1999 and 2000 were evaluated to 1) determine the magnitude of the natural variability of corn and soybean grain composition variables at the field scale, 2) describe and quantify the spatial structure of these variables, 3) assess the correlation between corn and soybean grain composition and several field chemical and physical properties, and 4) estimate and map the magnitude of the variation in the economic value of the processed soybean grain. The sampling density for the grain samples averaged about 16 points per hectare over about 12 hectares each of corn and soybean each year. Grain composition measurements were
conducted with an Infratech 1229 NIRT whole grain analyzer. Spatial variability for grain quality measurements was very low relative to the overall yield variability. The magnitude of the spatial variability of protein and oil was considerably larger in soybeans than in corn in absolute terms, but lower relative to the mean values. Correlations of grain composition variables with topography, soil chemical properties and grain yield were generally low, but soybean grain composition variables showed significant, albeit small, correlations with soil map units. Estimated economic returns to the farmer for on-the-go grain segregation based on spatial variability for grain composition variables were very low. A positive implication of this conclusion is that value-added specialty varieties (e.g., protein or oil) may be managed on a whole-field basis. Georeferenced crop scouting information was again collected in 2000-2001 in an effort to develop a sufficient database to satisfactorily
interpret yield variability of corn and soybean. Included in the data collection efforts were aerial and satellite imagery, plant density, plant height, relative corn leaf color, crop phenology, and leaf area index.
Impacts
The knowledge and experience gained from this whole-field evaluation of GPS-enabled technologies will help us better understand the relationships between potential yield-influencing factors and grain yield variability in corn and soybean. This knowledge will enable us to develop site-specific crop management strategies that will help improve net income for eastern U.S. Corn Belt cropping systems.
Publications
- Colonna, I.A., K.W. Ross and R.L. Nielsen. 2001. Comparison of organic matter interpolated maps from 0.5 and 2.5 acre grids using geostatistics. Agron. Abstr. (in press).
- Nielsen, R.L., I.A. Colonna, D.E.Maier and D.K.Morris. 2001. Field-scale spatial variability of grain composition in soybean and corn in Eastern Indiana. Agron. Abstr. (in press).
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Progress 10/01/99 to 09/30/00
Outputs
Data collection continued in a 49 ha field study established in 1998 at the Davis-Purdue Agricultural Center in eastcentral Indiana. The objective of the project is to evaluate site-specific crop management technologies for corn (Zea mays L.) and soybean (Glycine max L.) production in the eastern U.S. Corn Belt. Initial soil survey activities for the development of an intensive soil survey (Order 1) were completed in fall 1999 with the collaboration of Gary Steinhardt (Purdue Agronomy) and three NRCS soil scientists. Final characterization of the soil units (further soil coring and analyses) is yet unfinished. To our knowledge, an Order 1 soil survey of this magnitude has no parallel in the U.S. to date. The soils knowledge gained from this effort will greatly enhance our ability to interpret and predict crop yield responses across the landscape. Soil electrical conductivity (EC) was mapped across the entire 49 ha research site in June 2000 with a Veris (r) soil EC
mapping tool. Comparisons with soil EC data mapped 12 months earlier on the northern half of the area indicated reasonable but not perfect similarity over time, especially in the shallower depth readings. One of the major differences between the two sampling times was surface soil moisture, the 1999 sampling being very dry and the 2000 sampling being very wet. The spatial variability for soil EC correlated somewhat with that of the soil map units of the Order 1 survey and the digital elevation map developed earlier in 1999. Weaker correlations exist between the spatial variability for soil EC and grain yields of either corn or soybean. Georeferenced grain composition samples from the 1999 harvest revealed significant spatial variability within the fields and among crop varieties planted. Georeferenced crop scouting information was again collected in 1999-2000 in an effort to develop a sufficient database to satisfactorily interpret yield variability of corn and soybean. Included in
the data collection efforts were aerial and satellite imagery, plant density, plant height, relative corn leaf color (chlorophyll meter), crop phenology, and leaf area index. Additionally, 1) poorly drained (surface wet) areas of the field were GPS-delineated during the very wet spring of 2000 and 2) georeferenced assessments of the severity of infestation by European corn borer (Ostrinia nubilalis) in the corn areas were made in September 2000. Analyses to date suggest that while grain yield variability may be explainable after the fact from particular subsets of georeferenced data collected during the season and soils data, the influence of and interaction with weather patterns makes it very difficult to predict future spatial variability for grain yield in any given field.
Impacts
Knowledge gained from this project will be valuable in helping determine whether variability for grain yield can be interpreted and predicted. Such interpretations and predictions will help growers better manage crop inputs to best optimize crop production efficiency and minimize potentially negative environmental impacts.
Publications
- D. Keith Morris, Gary C. Steinhardt, R.L (Bob) Nielsen, William Hostetter, Scot Haley, Gary R. Struben. 2000. Using GPS, GIS, and Remote Sensing as a Soil Mapping Tool. Proceedings of the 6th International Conference on Precision Agriculture. St. Paul, MN 17-20 July, 2000.
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Progress 10/01/98 to 09/30/99
Outputs
Data collection continued from a field study established at the Davis-Purdue Agricultural Center in eastcentral Indiana in 1998 designed to evaluate site-specific crop management technologies for corn (Zea mays L.) and soybean (Glycine max L.) production in the eastern U.S. Corn Belt. The general objective of the project is to determine whether sufficient geo-referenced data can be collected to adequately interpret or diagnose crop yield variability commonly documented through the use of GPS-enabled yield monitors. During the period covered in this report, the following geo-referenced datasets were created throughout the approximately 49 ha. study area: first order soil survey, topography, soil electrical conductivity, aerial infrared imagery on 8 separate dates, soil fertility based on 0.2 ha. grid samples, plant density, plant height, chlorophyll meter values (Minolta SPAD), grain yield, grain moisture, and grain composition. The relationships between grain yield
and these GIS datasets are currently being analyzed. As part of the project, several field computers and several GIS field data collection software programs were evaluated for their utility in collecting geo-referenced crop data.
Impacts
The knowledge and experience gained from this whole-field evaluation of GPS-enabled technologies will help us better understand the relationships between potential yield-influencing factors and grain yield variability in corn and soybean. This knowledge will enable us to develop site-specific crop management strategies that will help improve net income for eastern U.S. Corn Belt cropping systems.
Publications
- No publications reported this period
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Progress 10/01/97 to 09/30/98
Outputs
A field study was established at the Davis-Purdue Ag. Center in eastcentral Indiana in 1998 as part of an integrated approach to evaluating site-specific crop management technologies for corn (Zea mays L.) and soybean (Glycine max L.) production in the eastern Corn Belt of the U.S. Two major soil types represent the 12 ha. experimental site and differ substantially in natural drainage characteristics and topography. Soil test data on 0.2 ha. resolution plus two previous years' yield maps were available. Although the 1998 growing season was designed primarily for establishing the plot area, variable rate seeding treatments were evaluated in both crops. Grain yields did not respond to variable seeding rates in either crop. Future plans include intensive re-mapping of soil types and topography, plus weekly site-specific monitoring of crop development and plant stresses.
Impacts
(N/A)
Publications
- No publications reported this period
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Progress 10/01/96 to 09/30/97
Outputs
A two-year field study was completed in 1996 whose purpose was to identify a method of time measurement that would consistently relate to phenology among 14 dent corn hybrids. Comparisons among calendar time and four thermal time scales did not identify a single superior time measure. Due to its widespread use in the U.S. and the simplicity of its calculation, the Modified Growing Degree Day (MGDD) method of thermal time measurement was chosen as the preferred method of time measurement for the hybrid comparisons in this study. Differences in hybrid rates of emergence were minimal in both years of research. MGDD and calendar time linear rates of leaf collar development accurately defined leaf collar development during the intervals of VE to the final observed leaf collar stage (VFinal), VE to V10, and V10 to VFinal. Individual VE to V10 and V10 to VFinal linear regressions more accurately defined rates of leaf collar development than the single VE to VFinal linear
regression. Leaf collar development rates were significantly slower during the VE to V10 interval than during the V10 to VFinal interval. Significant differences in hybrid leaf collar development rates were observed for the VE to V10 and V10 to VFinal intervals. Significant hybrid differences in accumulations of MGDD and calendar time during the intervals of Planting to R1, Planting to R6, VE to R1, VE to R6, VE to VFinal, VE to V10, and V10 to VFinal were also observed. MGDD and calendar time accumulations for the intervals between R1 and R3 were similar among hybrids, while tending to be significantly different for the intervals in or including the later kernel development stages.
Impacts
(N/A)
Publications
- WUETHRICH, K. L. 1997. Phenology of Fourteen Diverse Hybrids of Dent Corn (Zea mays L.). M.S. Thesis. Purdue University, West Lafayette, IN.
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Progress 10/01/95 to 09/30/96
Outputs
Observations from studies conducted from 1991 to 1994 indicated that kernel dry weight of corn (Zea mays L.) decreased an average of one percent per percentage point decrease in grain moisture content during post-maturity drydown periods in the field. In 1995, kernel dry weights of fifteen diverse corn hybrids were measured during post-maturity drydown periods in a field study conducted in westcentral Indiana. Physiological maturity among the fifteen hybrids occurred at grain moisture contents of 23 to 30 %. Natural drydown of the mature grain in the field resulted in final grain moisture contents of 12 to 14 %. Kernel dry weight of eleven of the fifteen hybrids decreased significantly after physiological maturity occurred. No further dry weight loss was measurable after grain moisture contents decreased below about 15 %. Such changes in post-maturity kernel dry weight have not previously been documented in research literature, although farmer and seed company
experiences have been reported. Research field plots in 1996 were abandoned due to severe European corn borer and cob rot damage, plus fall frost damage to immature grain. The potential loss of kernel dry weight during natural drydown periods in the field will encourage some farmers to harvest at higher grain moisture contents and dry the grain artificially to increase their net income from corn production.
Impacts
(N/A)
Publications
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Progress 10/01/94 to 09/30/95
Outputs
Observations from studies conducted from 1991 to 1994 indicated that kernel dry weight of corn (Zea mays L.) decreased an average of one percent per percentage point decrease in grain moisture content during post-maturity drydown periods in the field. In 1995, kernel dry weights of fifteen diverse corn hybrids were measured during post-maturity drydown periods in a field study conducted in westcentral Indiana. Physiological maturity among the fifteen hybrids occurred at grain moisture contents of 23 to 30 %. Natural drydown of the mature grain in the field resulted in final grain moisture contents of 12 to 14 %. Kernel dry weight of eleven of the fifteen hybrids decreased significantly after physiological maturity occurred. No further dry weight loss was measurable after grain moisture contents decreased below about 15 %. Such changes in post-maturity kernel dry weight have not previously been documented in research literature, although farmer and seed company
experiences have been reported. The potential loss of kernel dry weight during natural drydown periods in the field will encourage some farmers to harvest at higher grain moisture contents and dry the grain artificially to increase their net income from corn production. Grain samples from each sampling date were stored for further analysis, by kernel digestion procedures, to determine which kernel dry weight fractions accounted for the overall loss of kernel dry weight.
Impacts
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Publications
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Progress 10/01/93 to 09/30/94
Outputs
Field studies at two Indiana locations in 1993 suggest that annual ryegrass may be an acceptable winter cover crop alternative to the more commonly used winter wheat and winter rye. Favorable characteristics of annual ryegrass that were observed during these studies included quick seedling emergence, good fall growth, a more dense canopy as compared to winter wheat and winter rye, less height than winter rye, and adequate dry matter yield. Grass cover crop treatments produced statistically similar corn grain yields. Numerically, however, there was a tendency for greater yield reductions when the late maturing ryegrass was used as a cover crop. The thermal responses of five corn hybrids to delayed planting were evaluated at four locations in Indiana and Ohio in 1993. The hybrids were planted once every three weeks from early May through early June, for a total of 3 plantings. Delayed planting shortened thermal growth intervals throughout the season. Delayed planting
decreased the thermal interval between planting and silk emergence, especially at the northern locations. Delayed planting significantly decreased the thermal interval between mid-silk and kernel black layer development. The effect was somewhat more pronounced at the northern locations, but not as consistent as the location effects on GDD to mid-silk. Later maturity hybrids were affected more so than the earlier maturity ones.
Impacts
(N/A)
Publications
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Progress 10/01/92 to 09/30/93
Outputs
Research projects were conducted in 1993 in two major areas of emphasis. Field studies were established in WC Indiana, SE Indiana, SW Ohio, and NW Ohio to evaluate the influence of delayed planting on the phenological responses of five maize hybrids to Growing Degree Day accumulations. This experiment was conducted in cooperation with Dr. Peter Thomison, Agronomy Dept., The Ohio State University, Columbus, OH. Planting dates were early May, late May, and early June. The five maize hybrids evaluated encompassed a range of relative maturity from `97-day' to `123-day' classifications. Data were recorded on emergence rate, leaf stage development, flowering rate, grain development, grain maturation timing, and grain moisture loss in the field. Less thermal time was required for grain maturation to occur as planting was delayed by about 6 GDD per day of delayed planting. The decrease in thermal time to reach grain maturation with delayed planting was the result of decreased
GDD from planting to silking as well as fewer GDD from silking to grain maturation. A second field experiment was established in SC Indiana and SE Indiana to compare the cover crop potential of several annual ryegrass varieties with winter wheat and winter rye for no-till corn following soybeans. The success of fall establishment and winter survival of the ryegrasses was comparable to that of the two small grains. By late April, light interception by the cover crop canopy averaged 78% for the ryegrasses and 66% for the small grains.
Impacts
(N/A)
Publications
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Progress 10/01/91 to 09/30/92
Outputs
One major field study was conducted in 1992. The primary goal of the project wasto better understand corn's phenological response to thermal time in order to improve the accuracy of hybrid maturity selection in replanting or delayed planting situations. Results indicated that, compared to "optimum" early May seedings, thermal time (GDD) from seeding to anthesis and physiological maturity decreased significantly for late May and early June seedings. Final leaf number decreased with later seedings, accounting for much of the decreased thermal time to anthesis. Additional decreases in thermal time from anthesis to physiological maturity reflected premature kernel black layer development, likely caused by sub-optimal air temperatures late in the grain filling period for the delayed seedings. These observed effects of delayed seeding suggest that hybrid selection decisions based on GDD ratings determined from "normal" plantings would unnecessarily hasten switches in hybrid
maturity in delayed planting or replanting situations. The results from this field study will increase growers' abilities to accurately select hybrid maturities to match the remaining length of the growing season when faced with delayed planting or replanting situations. In so doing, the individual grower's risk of incurring a killing fall frost before a hybrid has fully matured will be lessened.
Impacts
(N/A)
Publications
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Progress 10/01/90 to 09/30/91
Outputs
Field research conducted in 1991 included (1) Corn yield and yield component response to intra-row plant spacing variability, and (2) Summer weed suppression by cover crop surface mulch in a no-till corn system. The main objective of Study #1 was to determine the yield response of corn to increasing levels of intra-row plant spacing variability (PSV), as measured by the standard deviation of plant-to-plant spacing within the row. Results from small plot studies suggested that yield decreased 38 kg/ha for each 2.5 cm increase in PSV, while results from large plot studies suggest that the yield loss was closer to 126 kg/ha per 2.5 cm increase in PSV. The yield losses were due primarily to decreases in kernel rows per plant and number of kernels per row. The main objective of Study #2 was to evaluate the ability of the surface mulch from wheat or rye cover crops to suppress germination and/or growth of summer weed species in a no-till corn production system. Results from
1991 suggested the use of small grain covers plus a burn-down herbicide effectively suppressed summer weeds where endemic weed pressure was low. However, where endemic weed pressure was severe, especially grassy species, the small grain cover crop mulch could not suppress weed growth long enough to prevent significant yield loss to the corn.
Impacts
(N/A)
Publications
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Progress 10/01/89 to 10/30/90
Outputs
Field research in 1989-90 evaluated 1) intra-row plant spacing variability, 2) imazaquin carryover residues, and 3) limestone-based seed coating in maize (Zea mays L.). In previous years' studies (1987-88), intra-row plant spacing variability (PSV) caused yield losses in maize of approximately 251 kg per 2.54 cm standard deviation of plant-to-plant spacing. Data from 1989 field studies were much less conclusive, in part due to excellent growing conditions that likely overcame the yield-limiting nature of PSV in maize. Simulated carryover residues (20 and 40 ppm) of imazaquin (ScepterTM) had little effect on maize seedling emergence, delayed early growth and development dramatically, caused death of plants subsequent to emergence, delayed the onset of silk emergence and pollen shed, but did not disrupt the pollination process, reduced yield 55 and 85% in a year where excessive soil moisture occurred early, and caused increased harvest grain moisture due to the delayed
pollination period. Technology exists for adding weight and volume to small graded seed maize by coating it with a limestone-based material. Such seed coating increased seed weight 34% compared to uncoated seed. Emergence was somewhat delayed for coated seed, but final plant density was similar for all treatments. The seed coating reduced grain yield by about 9% versus uncoated seed of the same lot.
Impacts
(N/A)
Publications
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Progress 10/01/88 to 09/30/89
Outputs
Research emphasis in 1988-89 was related to the importance of optimizing stand establishment uniformity in maize (Zea mays L.). The 1989 data have not been analyzed to date. Specific objectives were to determine the effect of intra-row planting spacing variability (PSV) on corn grain yield and yield components of 2 hybrids differing in ear size flexibility. Studies were conducted at 4 locations in WC, NE, SC, & SW Indiana; each as a randomized complete block designreplicated 4 times. Treatments included 3 plant densities within which zero, low, medium, and high PSV levels were established during planting with pre-determined mixtures of gaps and doubles. Due to the drought of 1988, 2 locations (SC & SW) were not useable. Neither hybrid ear size flexibility nor plant density consistently influenced the effect of increased PSV levels on grain yield. Increased PSV decreased grain yield of the flexible ear size variety but not the constant ear size variety at the WC
location. Yield losses at this location were not as great as were observed in 1987 with the same variety. Increased PSV decreased grain yield of the constant ear size variety grown at the greatest seeding rate at the NE location, but not the flexible ear size variety. Yield losses due to PSV at this location and seeding rate (approximatly 3.5 bushels/acre per unit increase in PSV) were nearly as great as those observed in 1987. Other than the one instance at the NE location, seeding rate did not influence the effects of PSV on grain yield.
Impacts
(N/A)
Publications
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Progress 10/01/87 to 09/30/88
Outputs
Research emphasis in 1987-88 was related to the optimization of stand establishment in maize (Zea mays L.). Specific objectives were to determine the effect of intra-row plant spacing variability (PSV) on corn grain yield and yield components at two locations in west central (PAF) and south central (FPAC) Indiana. Treatments included uniform intra-row plant spacing and low, medium, and high PSV established at planting with a mixture of gaps and doubles. Treatments were arranged in a randomized complete block design replicated 8 and 4 times at PAF and FPAC, respectively. Plant height at growth stage V6 was reduced slightly by increasing levels of PSV compared to the uniform control. By growth stage R1, however, no effects of PSV on either plant or ear height were observed. Measurements of PAR above and beneath the leaf canopy at growth stage R2 indicated that the greatest PSV treatment reduced intercepted photosynthetically active radiation by 4.9%. Corn grain yield
decreased as plant-to-plant spacing became more variable. The rate of yield decrease at each location was approximately equal, 4.14 and 4.28 bushels per acre for every inch increase in standard deviation of plant-to-plant spacing at PAF and FPAC, respectively. Decreased kernel number per row appeared to be primarily responsible for the grain yield decreases. Data from a survey of 30 farms in east central Indiana indicated that average intra-row plant spacing deviated from the desired by plus or minus 8.4 cm.
Impacts
(N/A)
Publications
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Progress 10/01/86 to 09/30/87
Outputs
The objective of the research emphasis in 1987 was to determine the effect of intra-row plant spacing variability (PSV) on corn (Zea mays L.) grain yield and yield components at two locations in west central (PAF) and south central (FPAC) Indiana. Treatments included uniform intra-row plant spacing and low, medium, and high PSV established at planting with a mixture of gaps and doubles. Treatments were arranged in a randomized complete block design replicated 8 and 4 times at PAF and FPAC, respectively. Plant height at growth stage V6 was reduced slightly by increasing levels of PSV compared to the uniform control. By growth stage R1, however, no effects of PSV on either plant or ear height were observed. Measurements of PAR above and beneath the leaf canopy at growth stage R2 indicated that the greatest PSV treatment reduced intercepted photosynthetically active radiation by 4.9%. Yield and yield component data have not been analyzed yet. Data from a survey of
30 farms in east central Indiana indicated that average intra-row spacing deviated from the desired by plus or minus 8.4 cm. Standard deviations for actual plant spacing averaged 4.52, ranging from 2.11 to 9.26.
Impacts
(N/A)
Publications
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Progress 10/01/85 to 09/30/86
Outputs
1986 field studies included: 1) Two yellow dent corn hybrids grown in 38 and 76-cm row spacings at 44460, 59280, 74100, and 88920 plants per hectare in four sites in Indiana. Up to 13% greater grain yield occurred in the narrower row spacings across environments in 1985. The largest yield increases occurred in the narrower row spacing across environments in 1985. The largest yield increases occurred at the adapted plant density for each environment. Stalk breakage below the ear was more prevalent in the narrower rows, thus increasing the potential for harvest loss. In west central Indiana, the narrower rows increased grain yield of the 115-day hybrid, but not the 100-day hybrid. 2) The ability of the plant growth regulator ethephon, (2-chloroethyl) phosphonic acid, to reduce stalk breakage in yellow dent corn was evaluated at two locations in Indiana in 1986. Plant height was reduced 53 cm and stalk breakage below the ear was reduced 26% by application of the PGR
at growth stage V7 in 1985. Total grain yield was reduced 314 kg/ha by the treatment, but harvestable grain yield was increased 1258 kg/ha due to increased standability and harvesting efficiency. Segment weight and rind thickness of the second internode above the soil surface were increased 14 and 26%, respectively, by the PGR. Crushing strength of the same internode, however, was reduced 34% by the PGR.
Impacts
(N/A)
Publications
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Progress 01/01/85 to 12/30/85
Outputs
1985 field studies included: 1) Two yellow dent corn hybrids grown in 38 and 76-cm row spacings at 44460, 59280, 74100, and 88920 plants per hectare in four sites in Indiana. Up to 13% greater grain yield occurred in the narrower row spacing across environments. The largest yield increases occurred at the adapted plant density for each environment. Stalk breakage below the ear was more prevalent in the narrower rows, thus increasing the potential for harvest loss. At the westcentral Indiana location, the narrower rows increased grain yield of the 115-day hybrid, but not the 100-day hybrid. 2) The ability of the plant growth regulator ethephon, (2-chloroethyl) phosphonic acid, to reduce stalk breakage in yellow dent corn was evaluated at a southcentral Indiana location. Plant height was reduced 53 cm and stalk breakage below the ear was reduced 26% by application of the PGR at growth stage V7. Total grain yield was reduced 314 kg/ha by the treatment, but
harvestable grain yield was increased 1258 kg/ha due to increased standability and harvesting efficiency. Segment weight and rind thickness of the second internode above the soil surface were increased 14 and 26%, respectively, by the PGR. Crushing strength of the same internode, however, was reduced 34% by the PGR.
Impacts
(N/A)
Publications
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Progress 01/01/84 to 12/30/84
Outputs
Field studies conducted in 1984 include: 1) Growth analysis of two corn hybrids grown in 38- and 76-cm row widths. An increased crop growth rate (CGR) was observed for the narrower rows throughout much of the growing season. Analysis of the components of CGR suggested that the increase resulted from an increase in LAI versus net assimilation rate. Concentrations of N, P, and K in the plants were not affected. Total nutrient uptake, however was increased in 38-cm rows. 2) Two hybrids were grown in 38-cm and 76-cm rows at 44460, 59280, 74100, and 88920 plants per hectare in six environments across the state. A 3-5% yield increase due to narrower row widths was observed across environments. Larger yield increases were observed at lower plant densities. Stalk breakage below the ear was more prevalent in the narrower rows, thus reducing harvestable yield. 3) The use of a plant growth regulator, ethephon, to enhance stalk lodging resistance in the narrower rows was
evaluated. Plant height was shortened from 229 cm to 175 cm and stalk lodging from 43% to 8% in untreated plots and treated plots, respectively. 4) Effects of nitrogen fertilizer rates and plant densities were evaluated with two popcorn hybrids and one dent corn hybrid. Increased plant density had no effect on grain yield or popping quality, but did increase stalk lodging. Optimum nitrogen rates for grain yield were lower for popcorn compared to dent corn. Popping expansion volume increased as nitrogen fertility rate increased.
Impacts
(N/A)
Publications
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Progress 01/01/83 to 12/30/83
Outputs
Several research studies wre initiated throughout the state in 1983. The crop season was marked by extreme heat and little rainfall, thus allowing evaluaton of treatments under drought conditions. Projects included were: 1. Evaluation of plant density and fertilizer nitrogen rates on yield, standability, and popping quality of popcorn. Neither set of treatments had any significant effect on yield. Standability was reduced by greater plant densities, and differential hybrid response was detected. Nitrogen rate had no significant effect on standability, although greater N rates tended to reduce it. 2. Evaluation of plant density and hybrids on dent corn production in no-tillage versus conventional tillage. Grain yield decreased in both systems as plant density increased from 29,640 plants per hectare (pph) to 88,920 pph. Interactions of hybrids, plant densities, and tillage systems were observed for stalk breakage, barenness, and grain yield. 3. In comparison
of 15-inch and 30-inch row spacing on the growth and development of two corn hybrids, the narrower rows increased grain yields by 10% for both the full-season and early- season hybrids. Total plant dry matter, leaf area, and interception of avialable sunlight were also increased through the use of narrow rows.
Impacts
(N/A)
Publications
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