1. On-Farm Assessment of Nitrogen Use and Management in Irrigated Corn Production in Nebraska

High-yield irrigated crops have large nitrogen (N) requirements. For example, N uptake of a corn crop that yields 207 bu ac -1 (~13 t/ha) is about 180 lb N ac-1 (200 kg N ha-1). The amount of N that is not provided by indigenous sources (mineralization of previous crop residue and soil organic matter) needs to be supplied by crop producers through N fertilizer. High-yield irrigated corn accounts for 74% of total annual corn production of 1260 million bushels in Nebraska. With approximately 70,000...