Farmland Nutrients Balance and Dynamic Variation Tendency of Soil Nutrients on County Level in Purple Hilly Area of Qianwei County, Sichuan Province

According to statistical material and analytic data of soil related, the farmland nutrients balance and the dynamic changing tendency of soil nutrients during nearly 15 years (from 1985 to 1999) in Qianwei county were discussed. The result showed that in 1990s, the nitrogen in farmland was changing from equilibrium to surplus; the content of phosphorus was varying throughout from deficiency to surplus, it is surplus over 50 percent at present time; the potassium was deficient all along with high proportion. Meanwhile, comparing the content of soil nutrients between 1981 and 2000, the dynamic changing tendency during nearly 20 years was analyzed, the effect of farmland nutrients balance on soil nutrients level was discussed also, and the regulating ways relevant was given.