NITROGEN, PHOSPHORUS AND LAND DEMANDS AT THE US REGIONAL LEVEL: A PRIMAL APPROACH
基于预期利润最大化的一阶条件，开发了一种估计区域层面氮、磷和土地需求的方法，并应用于美国玉米带各州数据，发现玉米生产技术存在显著区域差异，且化肥需求对自身价格变化的响应随时间减弱。
A primal approach for estimating nitrogen, phosphorus and land demands at the regional level is developed based on the first‐order conditions for expected profit maximisation. The approach is applied to State‐level data on corn production in the US Corn Belt. The empirical results suggest that technologies in corn production differ significantly across the region, and, consistent with earlier studies in Ireland, fertiliser demands have become less responsive to own‐price changes over time. These results are consistent with structural and technological changes that have occurred in agriculture.