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1. Soybean Nitrogen Aquisition and UtilizationBecause of its high seed protein concentration soybean has a huge nitrogen demand, about 350 IbdA for a 65-bu/A crop. The nitrogen is supplied by two acquisition systems that operate in tandem. In early season the plant uses soil nitrate; later its nitrogen is acquired largely through Nz fixation. On highly fertile, Midwestern soils nitrate utilization peaks at about R3 and then declines sharply. With heavy nitrogen fertilization peak nitrate utilization can be extended through R5, but ordinarily... |
2. Site Specific Nitrogen and Irrigation Management Across Nebraska Agro-ecological ZonesNitrogen leaching below hrrow irrigated ground has caused nitrate contamination in Nebraska's groundwater. Alternate row irrigation and alternate row nitrogen fertilization is proposed as a method to decrease water use and decrease nitrogen leaching. Nitrogen was applied at a uniform and variable rates based on spring grid sampling for nitrate and soil organic matter. The experiment was conducted at three sites in Nebraska that represent a range of growing conditions. At these sites the average growing... |
3. Site-Specific Nitrogen and Irrigation Management Across Nebraska Agro-Ecological ZonesNitrogen leaching below hrrow-irrigated ground has caused nitrate contamination in Nebraska's groundwater. Alternate row hrrow irrigation and alternate row nitrogen fertilization is proposed as a method to decrease water use and decrease nitrogen leaching. Nitrogen (N) was applied at a uniform and variable rate based on spring grid sampling for nitrate. The experiment was conducted at three sites in Nebraska that represent a range of growing conditions. At these sites, the average growing degree-days... |
4. Effect of Phosphorus and Potassium Fertilization on Corn Development and Root Distribution in Conservation TillageIn conservation tillage systems, like no-till (NT) and strip-till (ST), phosphorus (P) and potassium (K) typically become vertically and/or horizontally stratified in the soil. This stratification has the potential to make P a nd K less available and to limit corn yield. The objective of this study is to determine the infl uence of tillage and P and K placement and rate on soil P and K content, soil water status, root and shoot development, and grain yield of corn. The experiment was arranged in... |
5. 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 |
6. Integration of Ultrasonic and Active Canopy Sensors to Estimate the In-Season Nitrogen Content for CornThe objectives of this research were to: (i ) determine the correlation between active canopy sensor (ACS) assessments of N status and ultr asonic sensor measurements of canopy height at several growth stages for corn receiving varying am ounts of N, (ii) test the ability of both sensors to distinguish N-mediated differences in canopy development and (iii) test the integrated use of both sensors. This experiment was conducted with varying N rates in an existing long-term study and farmer's fields... |
7. Field Estimation of Ammonia Volatilization from Surface-applied UreaAccurate estimation of the potenial for NH3 volatilization from urea-based fertilizers is an important step in optimizing Nuse efficiency from these fertilizers. Published estimates of volatilization from surface-applied urea vary widely. Citations listing losses from 2% on up to 80% from various systems can be found. Consequently, many growers, to protect themselves, will apply urea at higher than recommended rates, assuming some arbitrary level of loss will occur. The objectives of the research... |
8. Soil and Soybean Responses to Planting into Terminated Prairie StripsPrairie strips are a new conservation practice that are currently implemented in 14 Midwest US states. Prairie strips have been shown to reduce runoff, increase soil health, retain sediment and nutrients, increase biodiversity and have no effect on surrounding crop yield. Due to the comprehensive improvements to soil health under prairie strips, researchers and growers are interested in rotating them on 10-15 year cycles. We have little-to-no knowledge on the effects of planting crops in... C. Dutter, M. St cyr, M. Mcdaniel, C. Carley, A. Singh |
9. Corn Grain Yield Response to Nitrogen Rate Timing, Source, and Nitrification Inhibitor in MissouriNitrogen response depends on several factors including weather conditions, soil N supply capacity, previous crop in rotation, plant population, and fertilizer management practices. Fertilizer management practices include fertilizer rate, source, application timing, placement, and use of nitrogen stabilizer. In Missouri, the nitrogen fertilizer rate recommendations for corn are based on the yield goal equation. This equation includes the target plant population, pounds of nitrogen removed per thousand... G. Singh , K. Nelson, G. Kaur , J. Lory, M. Davis, L. Abendroth, H. Naumann, J. Calhoun, J. Chlapecka, W. Bradley, C.J. Ransom, R. Carson, P. Pal |