基于三因素二次回归通用旋转组合设计试验，得出西北干旱地区宁夏盐池县农牧交错区苜蓿灌溉定额、施氮量和施磷量与产量效应的优化回归数学模型．经模型解析，得到了各因素影响苜蓿产量的规律和特点；经模型寻优，求出了在不同目标产量下的最优水、肥组合方案．这对类似干旱地区的节水灌溉具有指导意义． Based on the three-factor quadratic regression general rotation combination design test, the optimal regression mathematical model of alfalfa irrigation quota, nitrogen application rate, phosphorus application rate and yield effect was obtained in the agro-pastoral zone of Yanchi county, Ningxia. Through the model analysis, the rules and characteristics of various factors affecting the yield of alfalfa were obtained. Based on the model optimization, the optimum combination of water and fertilizer under different target yields was obtained. This is instructive for water-saving irrigation in similar arid areas.