Analysis on coordinate effect of nitrogen and phosphorus and precipitation on various farmland ecological systems in different precipitation years

In the dryland-agriculture areas in south mountain region of Ningxia，a field experiment was conducted on the fertilization model of spring-wheat and the effect of fertilization and precipitation on its production．The result showed that nitrogen had biggest effects on production，phosphorus was the second，and precipitation was the last．The paper introduces the rational fertilization in different precipitation years，and analyzes the fertilization plan for the highest and optimum production and their economic effects．