Economic and Environmental Implications of Soil Nitrogen Testing: A Switching‐Regression Analysis
通过转换回归模型分析内布拉斯加州玉米种植区土壤氮测试对氮肥使用、作物产量和净收益的影响，发现氮测试能帮助农民在不确定土壤残留氮量时减少施肥而不减产，但效果取决于种植历史和土壤特性。
Abstract A simultaneous equations, or “switching‐regression,” model is developed to assess the impact of soil nitrogen (N) testing on N fertilizer use, crop yields, and net returns in corn growing areas of Nebraska. The results indicate that when there is uncertainty about the quantity of available “carry‐over” N, N testing enables farmers to reduce fertilizer use without affecting crop yields. However, the value of information from N tests depends critically on cropping history and soil characteristics. These findings have implications for environmental and technology transfer policies designed to reduce nonpoint source water pollution.