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1. Application of the Ceres-maize Model to Maximum Yield ResearchMaximum yields are obtained when as much assimilate as possible is partitioned into the grains of corn. The amount partitioned into the grains depends on several major factors. Grains per unit area is probably the most important of these factors. Other important considerations for grain filling in- clude the duration of the grain filling period, the amount that can be repartitioned from stem storage to the grains, the photo- synthesis rate, and the temperature. Several factors influence the number... |
2. Effect of Residual Profile Nitrate on Corn Response to N Fertilization in WisconsinResearch in several Great Plains and Western states has shown that crop yield response to fertilizer N is closely related to the amounts of residual nitrate in soil profiles. Based on this work, nitrogen fertilizer recommendations in these low-rainfall areas are adjusted to reflect the contribution of residual nitrate to the total crop nitrogen requirement. Use of residual profile nitrate data in development of N fertilizer recommendations has received much less research attention in the higher rainfall... |
3. Establishing (and Differentiating) On-farm Research and Demonstration TrialsAs the 1990s begin, funding agencies are looking beyond the traditional definition of who does "research." While university, USDA and private industry have traditionally conducted research in the past, grassroot organizations, local agency personnel and individual farmers are now proposing and implementing research of various types. An overall trend seems to be for research experiments to be evaluated on farmersf fields. Some of this movement may be a political statement against traditional methods... |
4. The Effect of Tillage and Lime Rate on Soil Acidity and Grain Yields of a Corn-Soybean RotationModern tillage systems, such as reduced tillage and no-tillage systems, provide shallow incorporation of surface applied materials at best. Because of concern of over-liming the surface few inches of agricultural soils, producers either reduce lime rates (and apply more often) or perform some sort of soil inversion to mix the lime deeper into the soil profile. The objectives ofthis field study were to evaluate the effects of tillage, lime rate and time of limestone application on corn and soybean... |
5. Varying Nitrogen and Seeding Rates of Corn Across Productivity Regions in FieldsA field study was conducted fiom 1999 to 2001 to determine the effects of variable seeding rates and variable nitrogen rates on corn (Zeu muys L.) in southern Ihois. In whole field experiments, variable seeding rates ranging fiom 18,000 to 38,000 seeds ac-' in 4.000 seed increments were planted in randomized strips (in a randomized complete block design) across the field that had soils with varying productivity based upon historical yield maps. From the yield data it was determined that the optimum... |
6. Using Historical Yield Patterns in Fields as a Management Tool to Variably Apply NitrgenIn whole field studies in southem Illinois a uniform rate of N application was compared with variably applied rates of N based upon historical crop yields for each field. The fields used were partitioned in "low". "medium", and "high" zones of productivity depending upon the normalized yield of the preceding 5 to 10 years of crops grown. Two formulas were used to variably apply nitrogen. One formula (VRN-One) calculated a N rate that favored more fertilizer in "high" productivity regions and less... |
7. Relationship of Mehlich-3 ICP and Mehlich-3 Colorimetric Phosphorus Determinations with the Bray-P1 ExtractantThe Bray P1 extractant has traditionally been the common extractant used for soil testing in the Midwest and Great Plains. while the Olsen P tests has been the dominant phosphorus (P) extractant used in many westem states. The use of the Meldich-3 extractant for determining soil test P in private and state operated soil test laborato~ies becotne more commonplace in recent years. The ability to extract multiple elements is a 11lajor advantage of the Mehlich-3 test. While the Mehlich-3 test is often... |
8. Periodic Deep Tillage of No-till Corn and Soybean Systems in Southern IllinoisLow organic matter and low available moisture supplying soils in southern Illinois lend themselves to no-tillage crop production, but concern about compaction and rooting depth have led some to employ the use of periodic tillage. A field study was conducted at two locations in southern Illinois between 2000 and 2006 to evaluate the effects of periodic deep tillage (ripping 16-18 inches [40-45 cm] with minimum surface disturbance style shanks) prior to corn or soybean production. Deep tillage occurring... |
9. Soil pH and Manganese Effects on Roundup Ready SoybeansSoybean 'flas'h is a general yellowing of th e upper soybean canopy thought to be associated with high rates of glyphosate and reduced levels of manganese (Mn) with glyphosate-resistant soybeans. Several field sites varying in soil Mn levels and some with within field variable pH levels were evaluated between 2004 and 2006 for re sponsiveness of soybeans to glyphosate rate and Mn treatments. The objectives of this study were to 1) evaluate the effects of foliar applied Mn and soil applied Mn on yiel... |
10. Nitrogen Availability of Treated and Raw Dairy ManureThere is minimal information on the nitrogen (N) availability and composition of treated manures. Knowing how N availability differs w ith manure treatment will result in better N crediting guidelines. Raw dairy manure and anaer obically digested manure were incubated with five typical Wisconsin soils for 112 d. Net N mineralized from the different N sources were compared. Nitrogen mineralizatio n differed by manure type and also by soil. Overall, the digested slurry and the digested separated liquid... |
11. Responses To K Fertilizer On High Testing SoilsSoil testing is the foundation for nutrient management decisions, and is based test method research and calibration models in the Midwest has been generated in the public sector by Land Grant Universities (LGU) over the last 75 years. The successes of soil testing over the past three decades has been in large part been due to the inherent value of the testing method, monitoring over time, and adoption of precision Ag technology. Soil testing for potassium (STK) in the Midwest, is based on the correlation... |
12. Comparison of Congranulated Fertilizer to Blends with S and Zn in Corn and SoybeansHigh yielding corn and soybean production systems in Missouri have renewed an interest in micronutrient management such as sulfur (S) which is essential for protein formation and zinc. (Zn) which is important for enzymes and metabolic reactions. Yield increases due to sulfur applications are more likely to occur during cool, wet springs when mineralization and crop growth are slow as a result of a decrease in atmospheric sulfur deposition. Soil tests in 2010 indicated that over 60% of the samples... M. Caldwell, K. Nelson, B. Burdick |
13. Corn Response to Starter Phosphorus in Addition to Fertilizer Banded with Strip-tillageProducersoften question the need for starter fertilizer application in addition to deep band with strip-tillage. The objective of this study was to evaluate the effect of phosphorus (P) starter on corn (Zea mays) in addition to deep-banded application. A study was conducted at two locations, one under supplemental irrigation and one dry land, with a corn-soybean crop rotation established in the spring of 2006. Strip-tillage was completed before corn in the rotation and soybean was planted without... |
14. Integrating Management Zones and Canopy Sensing for Improved Nitrogen Recommendation AlgorithmsActive crop canopy sensors have been studied as a tool to direct spatially variable nitrogen (N) fertilizer applications in maize, with the goal of increasing the synchrony between N supply and crop demand and thus improving N use efficiency (NUE). However, N recommendation algorithms have often proven inaccurate in certain subfield regions due to local spatial variability. Modifying these algorithms by integrating soil-based management zones (MZ) may improve their accuracy... J. Crowther, J. Parrish, R. Ferguson, J. Luck, K. Glewen, T. Shaver, D. Krull, L. Thompson, N. Mueller, B. Krienke, T. Mieno, T. Ingram |
15. Comparison of Ground-Based Active Crop Canopy Sensor and Aerial Passive Crop Canopy Sensor for In-Season Nitrogen ManagementCrop canopy sensors represent one tool available to help calculate a reactive in-season nitrogen (N) application rate in corn. When utilizing such systems, corn growers must decide between using active versus passive crop canopy sensors. The objectives of this study was to 1) determine the correlation between N management by remote sensing using a passive sensor and N management using proximal sensing with an active sensors. Treatments were arranged as field length strips in a randomized complete... J. Parrish, R. Ferguson, J. Luck, K. Glewen, L. Thompson, B. Krienke, N. Mueller, T. Ingram, D. Krull, J. Crowther, T. Shaver, T. Mieno |
16. Nitrate-N Loss Reduction: Scale of In-Field and Edge-of-Field Practice Implementation to Reach Water Quality GoalsStates in the Mississippi River Basin have developed state level nutrient reduction strategies in response to the 2008 Hypoxia Action Plan. The Iowa Nutrient Reduction Strategy was released in 2013 and the Nonpoint Source Nutrient Reduction Strategy Science Assessment reviews potential practice performance in reducing downstream nutrient loss and the scale of implementation that would be necessary to reach the Hypoxia Action Plan goal of a 45% reduction in riverine Nitrogen and Phosphorus. To... M. Helmers |
17. Applying N to legume-containing summer annual forage mixturesSummer annual forages are costly to implement but can provide quality grazing when cool-season perennial forages are less productive. Increasing botanical diversity may increase system productivity, thereby improving economic efficiency. However, there is debate as to whether annual legumes supply associated grasses with fixed N, leading to uncertainty regarding N application rates to legume containing summer annual forage mixtures. This experiment supplied three summer annual forage treatments... K. Mercier, C. Teutsch, S. Smith, E. Ritchey, K. Burdine, E. Vanzant |
18. Sensor-Based Fertigation Management for Production-Scale ApplicationsFertigation, the practice of applying fertilizer through irrigation water, offers many benefits as an in-season nitrogen application technique for irrigated corn production systems. Most notably, fertigation offers growers the opportunity to make multiple applications throughout the growing season, including late season applications during corn reproductive growth stages. Growers have traditionally determined the timing and number of fertigation applications using visual observations, irrigation... J. Stansell |
19. Nitrogen Fertilizer Rates and Nitrification Inhibitor Impact Agronomic and Economic Returns in Corn Production in KansasNitrogen (N) is an essential nutrient for corn crop, higher grain yields are related to N fertilizer application. Substances like the nitrification inhibitors (NI) were created to increase yields, promote Nitrogen Use Efficiency (NUE), and reduce N losses. The study was carried out in ten site-years in Kansas during 2017, 2018, 2019, 2020 and 2021 crop seasons, with the objective of evaluate the Nitrogen Agronomic Efficiency (NAE) in corn with and without the use of NI and to compare corn grain... P. Morinigo ferreira, D. Ruiz diaz |
20. Corn Response to Sulfur Fertilization in Central Iowa SoilsReductions in atmospheric sulfur (S) deposition and increased S removal through continuous cropping have led to S fertilizer responses in many crops. Responses to S fertilization by corn (Zea mays L.), however, have been inconsistent across the upper Midwest. Our objectives with this field study were to: (i) compare S sources for corn vegetative growth and grain yield; (ii) evaluate soil extractable S and S tissue concentrations at different growth stages as S diagnostic tools;... J. Kovar, C. Crespo, C. Hart, R. Roth, P. O'brien, S. Ruis |