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| Filter results5 paper(s) found. |
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1. Post-Harvest Soil Nitrate Following Corn Production in Eight Midwestern StatesApplying nitrogen (N) at economically optimal rates (EONR) and at times of rapid crop uptake are practices that are thought to minimize the amount of residual soil nitrate (RSN) in the profile that may be susceptible to loss. The objective of this study was to evaluate the effects of rate (0 to 280 lb N/a in 40 lb increments) and timing (pre-plant (PP) or PP plus V9 sidedress (PP+SD)) of N application on corn grain yield and RSN in the top 3 feet of soil relative to the calculated EONR. Thirty-two... C. Bandura, C. Laboski, J. Camberato, P. Carter, R. Ferguson, F. Fernandez, D. Franzen, N. Kitchen, E. Nafziger, J. Sawyer, J. Shanahan |
2. Variation in Internal N Efficiency of Corn and Impact on Yield-Goal Based N RecommendationsInternal N efficiency (IE) is defined as bushels per acre (GY) produced per pound of N per acre (PMN) in the plant at physiological maturity (R6). Internal N efficiency defines the required amount of plant N content at R6 in a yield-goal based N rate recommendations (currently used in 30 U.S. states) and several commercial N recommendation models. Commonly IE is assumed to be constant at an approximate value of 0.8 bu lb-N-1 in yield-goal based recommendations. Our research objective was... M. Shafer, J. Camberato, P. Carter, R. Ferguson, F. Fernandez, D. Franzen, N. Kitchen, C. Laboski, E. Nafziger, R. Nielsen, J. Sawyer, J. Shanahan |
3. A Weighted Classified Method for Nitrogen Zone DelineationEven though zone management in precision agriculture is a relatively new science. extensive research has been conducted on the best predictors for determining optimal nitrogen management zones in site-specific farming (Bausch et al., 2002; Fleming and Buchleiter, 2002; Franzen and Nanna, 2002, Hendrickson and Han, 2000; Lund et al.. 2002: Stenger et a].. 2002). Different techniques. varying from cluster analysis (Jaynes et al.. 2003; Kitchen et al., 2002: Ralston et al.. 2002) to neural networks... |
4. Comparison of Nitrogen Management Zone Delineation MethodsAn alternative to dense grid soil sampling for delineating residual soil N levels or N availability is a zone sampling approach. The zone approach assumes that soil N patterns are logically linked to some inherent causal effect, either natural or man-made. A number of delineation methods have been examined. including apparent soil EC (Kitchen et al.. 1999). yield mapping (Taylor and Whitney. 2001: Diker et al.. 2002), topography (Franzen et al.. 1998), aerial imagery (Williams et al., 2002 Sripada... |
5. Zone Delineation for Nitrogen ManagementManaging nitrogen through zone soil sampling has been shown effective in revealing residual soil nitrate patterns in North Dakota. Zone delineation has been constructed using several types of data, including yield maps, remote imagery, topography and soil EC sensor data. A study was conducted in North Dakota, Montana and Minnesota to evaluate zone delineation methods. Across the region, yield frequency maps, topography, remote inlagery and soil EC data were effective in helping to construct zones.... |