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1. In-Season Nitrogen Management for Sub-Surface Drip Irrigated CornIrrigation water and nitrogen @I) management for subsurface drip irrigated (SDI) corn was evaluated from 2004 through 2006 at the South Central Agricultural Laboratory of the University of Nebraska. SDI irrigation and N management strategies to increase both water and N use efficiency were compared to preplant N application for hrrow irrigation, commonly used in the area. Irrigation water levels of 100, 75 and 50% of measured evapotranspiration (ET) were applied with SDI, and N was applied in treatments... |
2. Skip-Row Configuration and Plant Density Effects on Sorghum Grain Yield and Yield Component in Southern NebraskaEqual spacing of sorghum rows typically results in the highest grain yield when soil water is adequate throughout the season, but skip-row plan ting may be a means to reduce water deficits during reproductive growth stages. We evaluated the effect of skip-row planting configuration and plant population density on grain yield, yield components and water use efficiency at five locations in a transect across southern Nebras ka where annual mean precipitation ranges from 300 to 900 mm yr -1. Three row... |
3. Use of Enhanced Efficiency Nitrogen Fertilizers To Reduce Leaching And Volatilization LossA laboratory study was conducted to explore interactions of N source and treatment with precipitation events on a coarse-textured soil. Nitrogen sources included urea-ammonium nitrate solution (UAN), UAN with additives of either nitrapyrin (Instinct �) or a carboxylated polymer (Nutrisphere-N�), or a polymer-coated dry urea (PCU) (ESN�). These products were applied to soil chambers which allowed measurement of ammonia (NH 3-N) volatilization or nitrate leaching over 31 days. Precipitation events... |
4. 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... |
5. Irigated Soybean Response to Nitroen Applied During Early Pod FormationHigh yield soybean ( Glycine max L.) has a high rate of N uptake during grain fill with maybe 2/3 of the N derived from the atmosphere. The rema ining needs to come from the soil. Previous research has found that the probability of response to N applied at early pod development (R3) for yield trials, including 44 with mean yield >60 bu/A, we re conducted in Nebraska to determine effect on soybean yield of applying N and S to the soil at R3. With 27 lb/A N applied and >60 bu/A yield, mean yield increases... |
6. Evaluation of Nitrate Leaching Potential from Slow and Controlled Release Nitrogen Fertilizer Application to Irrigated CornThe use of slow and controlled release nitrogen (N) fertilizers as a practice to reduce nitrate leaching from irrigated corn was evaluated on coar se-textured soils in the Central Platte River Valley of Nebraska in 2007 & 2008. Slow-releas e methylene urea (MU) and polymer-coated urea (PCU) were compared to a standard fertil izer of urea ammonium nitrate (UAN) solution. Flooding in 2007 severely impacted the study site, and results are not reported here. Saturated soils were common at the site in... |
7. Active-Optical Reflectance Sensing Evaluated for Red and Red-Edge Waveband SensitivityUncertainty exists with corn (Zea mays L.) N management due to year-to-year variation in crop N need, soil N supply, and N loss from leaching, volatilization, and denitrification. Active-optical reflectance sensing (AORS) has proven effective in some fields for generating N fertilizer recommendations that improve N use efficiency. However, various sensors utilize different wavebands of light to calculate N fertilizer recommendations making it difficult to know which waveband is most sensitive... G. Bean, N. Kitchen, J. Camberato, R. Ferguson, F. Fernandez, D. Franzen, C. Laboski, E. Nafziger, J. Sawyer, P. Scharf, J. Schepers, J. Shanahan |
8. Do Split-Nitrogen Applications in the Midwest Affect Corn Nitrogen Uptake and Grain Yield?It is hypothesized that split-nitrogen (N) relative to single near-planting applications improve corn (Zea mays L.) grain yield and nitrogen recovery efficiency, which can lessen environmental impacts of fertilization. However, these hypotheses have not been fully tested. A 49-site-year study across eight US Midwestern states over three years was conducted to compare near-planting (Single) and split-N (Split) applications. Three N application timings were evaluated [Single near planting, 40... J. Clark, F. Fernandez, J. Camberato, P. Carter, R. Ferguson, D. Franzen, N. Kitchen, C. Laboski, E. Nafziger, J. Sawyer, J. Shanahan |
9. 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 |
10. 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 |
11. Stover Removal Effects on Continuous Corn Yield and Nitrogen Use Efficiency Under IrrigationCorn (Zea mays L.) residue or stover is harvested as supplemental feed for livestock and is a primary feedstock for cellulosic biofuels. Limited information is available on corn residue removal effects on grain yield under different nitrogen (N) fertilizer rates, irrigation rates and amelioration practices to minimize soil carbon loss and soil erosion. A study on a silt loam in south, central Nebraska (2011-2016) evaluated potential interactions between stover removal (residue removal,... M. Schmer, V. Jin, A. Sindelar, R. Ferguson, B. Wienhold |
12. The Anaerobic Potentially Mineralizable Nitrogen Test as a Tool for Nitrogen Management in the MidwestThe anaerobic potentially mineralizable nitrogen (PMNan) test is a tool that can improve estimations of mineralizable nitrogen (N) and enhance nitrogen use efficiency. This tool may also help improve predictions of N uptake, grain yield, and the economic optimum nitrogen rate (EONR) of corn (Zea mays L.). A 32 site-year study across eight US Midwestern states was conducted to 1) compare the effect of incubation length (7-, 14-, 28-d), soil sampling timing, N fertilizer rate, and their... J. Clark, K. Sloan veum, F. Fernandez, J. Camberato, P. Carter, R. Ferguson, D. Franzen, N. Kitchen, C. Laboski, E. Nafziger, J. Sawyer, J. Shanahan |