Proceedings
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1. Are We Getting Better at Supplying Corn with Nitrogen?While the MRTN approach to making N rate guidelines is an improvement over previous methods, there remains the question about whether or not the database is sufficiently large to support the results adequately. This question is brought into focus when N rates used according to the MRTN guidelines are seen (or at least perceived) as being be inadequate in a given field or area in a given year. Other entities now making N rate recommendations may also market against the MRTN approach by raising do... |
2. Can Soil Information Better Inform Canopy Sensor Algorithms for Corn?Corn production is often limited by the loss of nitrogen (N) due to leaching, volatilization and denitrification. The use of canopy sensors for making in-season N fertilizer applications has been proven effective in matching plant N requirements with periods of rapid N uptake (V7-V11), reducing the amount of N lost to these processes. However, N recommendation algorithms used in conjunction with canopy sensor measurements have not proven accurate in many fields of the U.S. Cornbelt, resulting in... , N.R. Kitchen, J. Camberato, P.R. Carter, R.B. Ferguson, F.G. Fernandez, D.W. Franzen, F.G. Fernandez, E.D. Nafziger, C.J. Ransom, , J. Shanahan, G.M. Bean |
3. Comparison of Mehlich-3, Olsen, and Bray-P1 Procedures for Phosphorus in Calcareous SoilsFertilizer recommendations for P generally are based on soil testing. Although a variety of soil tests are reliable for evaluating plant available P of neutral or slightly acid soils. there is still uncertainty about appropriate soil tests and soil-test interpretations for calcareous soils. The Bray-P 1 and Olsen methods are the most widely used soil-test P methods in the North Central region. Extensive research has shown that the Bray-P1 test is reliable on neutral or acid soils but that it ten... |
4. Effect of Time and Rate of N Application on N use Efficiency and Surface Water Contamination with NitratesNitrate levels in excess of the public health standard of 10 mg N/1 in public water supplies along - with concern about hypoxia in the Gulf of Mexico have drawn renewed interest to improving fertilizer N use efficiency. Prior research has indicated that some farmers may be unkaowingly contributing to these problems. The objectives of this research were to: determine the effect of rate and time of N application on nitrate-N concentrations in water from tile lines and to evaluate the effect of pre... |
5. Foliar Fertilization and Fungicide Application for SoybeanConcerns over fungal diseases in soybean have renewed interest in applying pesticides for disease control with the goal of increasing grain yi eld. Interest has especially been sparked by discussions of the possibility of Asian Soybean Rust (Phakopsora pachyrhizi) spreading north to the North Central region. Because of increasing prices of soybean grain and traditional fertilizers, many Midwest grower s are considering mixing fluid fertilizers and fungicides for foliar application to soybean. Ex... |
6. Foliar Fertilization of SoybeansExtensive research addressed foliar fertilization of soybeans at reproductive stages during the 70s and 80s. The soybean plant has been characterized by markedly reduced root activity during late seed development and increased translocation of nutrients and metabolites fiom other tissue into the seed. This depletion of numents from leaves could result in decreased photosynthesis. leaf senescence. and lower grain yields. Researchers theorized that if nutrients were applied directly to the foliage... |
7. In-season N for Corn Reduced Nitrous Oxide Emissions and Drainage Water Nitrate ConcentrationFarmers want to get the N fertilizer they apply into their crop, not lose it to air and water. This can be difficult to accomplish during wet years when N loss processes are going strong. Applying N in-season can be difficult to accomplish during wet years, but reduces the odds that N will be lost before the crop has a chance to take it up. We compared 2 N management strategies (140 lb N/acre applied pre-plant and variable-rate N applied sidedress based on canopy sensor measurements) and 3 drain... |
8. Measuring Soil Quality Changes in Corn and Soybean RotationsSoil quality is described as the ability of the soil to sustain crop growth and development along with nutrient cycling and water infiltration and retention. One possible strategy to maintain or increase soil quality is crop rotation. Crop rotations have the potential to increase crop yields, disrupt diseaseand pest cycles, and when a legume is added to the rotation, reduce nitrogen fertilizer requirements. Although the long-term productivity and sustainability of agriculture are dependent on ma... M. Adams, G. Behke, E. Nafziger, M. Villamil |
9. Nitrogen Fertilization Requirement and Corn-Soybean Productivity in a Rye Cover Cropping SystemNitrogen (N) fertilizer inputs for intensive corn-based cropping systems can increase nitrate (NO 3 -N) concentrations in groundwater. Nitrogen tr ansport in surface water to the Gulf of Mexico is also an on-going issu e for the upper Mississippi river ba sin, especially areas with large corn and soybean acreage. Education and policy efforts have focused on i\provement in N application rate, timing, management, and crop N us e efficiency. However, additional means to reduce N loss are needed. R... |
10. Nutrient Management and Starter Fertilizer for No-till CornNo-till corn acreage has steadily increased in Illinois. No-till presents unique problems of nutrient stratification, increased surface residue, and cool, wet soils which may influence nutrient availability. Two experiments were initiated in 1993 at 4 locations to evaluate the response of no-till corn to: 1) primary N applications of anhydrous ammonia preplant, UAN broadcast preplant, and ammonia sidedressed at V6; 2) starter fertilizers with factorial combinations of N, P, and K banded 2 inches... |
11. One-Time Tillage of No-Till Crop Land: Five Years Post-TillageField research was conducted at two eastern Nebr aska locations to test the hypotheses that one- time tillage of no till (NT) land results in increased grain yield, reduced stratification of available soil phosphorus but reduced wet aggregate stabili ty, and increased soil organic carbon (SOC), without a long term effect on the soil microbial community. Research was conducted in long- term NT fields under rainfed corn [ Zea mays (L.)] or sorghum [Sorghum bicolor (L.) Moench.] rotated with soybea... |
12. Quantifying Corn Nitrogen Deficiency and Application Rate with Active Canopy SensorsPrecision agriculture technologies are an integral part of many crop production operations. However, implementation for N application has lagged, primarily due to lack of a viable system for variable N rate decisions. Ac tive canopy sensors have been developed as a tool to determine plant N stress deficiency and provide an on-the- go decision for implementing variable rate. Two general approaches could be implemented. On e is to plan on conducting canopy sensing each year, with a reduced N rate ... |
13. Starter Potassium for Corn: Why and WhenStarter fertilizer application can complement broa dcast P and K fertilization for corn and other crops. Questions about its use relate mainly to the conditions in which it is most effective (such as soil-test level, tillage syst em, and broadcast fertilization rates among others), application methods and rates that do not damage seedlings, and nutrient ratios. Many studies in Iowa and the Midwest have shown that starter mixtures (usu ally N-P or N-P-K) often increase early corn growth. Corn yie... |
14. The New Wisconsin Soil Test Recommendation ProgramThe modern Wisconsin soil testing program was originally developed in the early 1960's. It was revised rather thoroughly in 1970 and again in 1981. New research advances, additional correla- tion and calibration data, changes in user needs, and shifts in philosophical viewpoint make it necessary to periodically review the soil testing program and the recommendations that emanate from that program. The current revision is an attempt to incorporate additional research, eliminate certain inconsiste... |
15. Weed Control Timing Effects on Corn Yield Response to NitrogenNitrogen (N) rate guidelines for corn are under c ontinued scrutiny to maximize N use efficiency in order to minimize potential N losses to th e environment while maximizing economic returns to growers, especially with significant N fertilizer price increases in recent years. In-season crop stress can potentially affect corn N needs for optimum production. Recently, postemergence weed control has become more common with th e availability of glyphosate resistant corn hybrids. Delaying weed contro... |
16. Which Corn Nitrogen Fertilization Rate Tools Preforms the Best in the Midwest?Publicly-available nitrogen (N) rate recommendation tools are utilized to help maximize yield in corn production. These tools often fail when N is over-applied and results in excess N being lost to the environment, or when N is under-applied and results in decreased yield and economic returns. Performance of a tool is often based on the specific soil and weather conditions of a growing season. Research is needed to determine which tools are the most effective at recommending economical optimal N... |