Nitrogen fertilizer value of feedlot manure for irrigated corn production

Abstract

The efficient use of cattle manure nutrients for crop production is important to achieve economical farming and to protect water quality, but the nutrient availability, especially nitrogen (N), of stockpiled manure in semi‐arid environments under irrigation needs to be defined so that appropriate rates of application can be determined. The first year's effects of cattle feedlot manure on corn production in northwestern New Mexico were evaluated in a field study. Variable rates of N from cattle manure were compared with N from urea in 1992 and 1993. Corn yields and N uptake were increased by increasing N fertilizer and manure application from 7,210 to 12,177 kg ha^‐1 in 1992, and from 9,555 to 11,966 kg ha^‐1 in 1993. The grain yields were also highly correlated (R²=0.94) with corn tissue total nitrogen (TN). Two kg of manure‐N were equivalent to 1 kg of urea‐N in terms of plant uptake and yield response in the first year of manure application. No significant movement of nitrate occurred in the top 75 cm of the soil profile with the manure‐N rate up to 225 kg ha¹. Precise application of manure to a corn crop can be as effective as commercial N fertilizer for yield response and can have little threat to ground water quality.