An increasing number of
farmers have yield monitors on their combines that provide crop yield
data. Farmers are collecting the data but aren’t effectively using it for
future crop management strategies. One strategy is to use yield maps, soils
data and other geospatial data to precision-rate apply nitrogen in order to
efficiently use N for increased crop yields while reducing N fertilizer costs.
In 2002, the
In 2006, urea was preplant applied at variable rates to one-half of the irrigated wheat field, while one N rate was applied to the other half of the field. The N rates were based on a fall 2005 composite soil test, 40 lb/acre N soil credit for the 2005 soybean crop, and a base yield goal of 56 bu/A. The ‘check’ half of the field received 60 lb N/acre while the variable rate half received 30, 60, or 90 lb N/acre. The N rate prescription map (map 1) was generated with the SMS (AgLeader Technology) computer program using 2003-05 yield data. The urea was custom applied by Mainline Agronomy, Eldridge. After harvest, a profit/loss map (map 2) was generated to compare the profitability of the study. Conclusions cannot be made on this first year of data.
Map 1. N prescription map: black =
90 lb, Map 2.
Profit and loss map: black = high range,
grey = 60, and white = 30 lb N/acre. grey = mid range, and white = low range]
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