Effect of chemical fertilizer application on grain yield in Qitai County,Xinjiang Uygur Autonomous Region

Based on official statistical data from 1989 to 2005, the characteristics of chemical fertilizer application in Qitai County, Xinjiang Uygur Autonomous Region were investigated by time series analysis. Then the relationship between grain yield and chemical fertilizer application was established through correlation analysis. Results show that average chemical fertilizer application in the county is influenced by the price of grains and fertilizers. From 1989 to 2005, fertilization application increased from 65.65 kg·hm-2 to 159.43 kg·hm^-2 and peaked in 1998 at 196.6 kg·hm^-2. The proportion of NPK fertilizer is moderate and has clearly increased grain yield. A significant direct correlation exists between grain yield and chemical fertilizer application rate. With increase in chemical fertilizer application, grain yield increases by many folds. When chemical fertilizer application is above 170 kg·hm^-2, increase in grain yield ceases to be significant. The best strategy is to control fertilizer application amount to avoid the potential pollution and other negative impacts. This can be achieved by paying appropriate attention to scientific application of fertilizers and sustainable development of agricultural production.