Variable Environment and Market Affect Optimal Nitrogen Management in Wheat and Cattle Production Systems

Fertilizer nitrogen use efficiency (NUE) is about 33% worldwide. The application of crop models has the potential to improve NUE by allowing managers to optimize and synchronize N supply with crop demand. We used a wheat (Triticum aestivum L.) grazing model to predict optimal N rates that maximize either grain yield for a grain-only system or net economic return for a dual-purpose system for selected climate, soil water reserve, and market conditions. Simulated probabilistic distributions of optimal fertilizer N rates for grain-only wheat revealed a 55% chance that optimal N was