Abstract:Long-term trends of crop yields and soil fertility have been used as a means to evaluate the sustainability of intensive agriculture, soil management and fertilizer application. Effect of soil fertility and long-term fertilizer application on the tendency of wheat and maize yield was analyzed based on 24-year data (1987-2010) collected from 32 sites, two treatments (no-fertilizer and normal fertilizer, which means NPK with straw) of long-term experiment of Drab Fluvo-aquic soil. The results showed that the average contribution rate of soil fertility to wheat and maize yield was 51.4% and 54.0%, separately. And the coefficient of variation (CV) of the contribution rate was 39.0% in wheat season, and 41.2% in maize season. The yields of wheat and maize in no-fertilizer field decreased slowly at a rate of 4.1kg/hm2 and 96.6 kg/hm2 per year, separately. In normal fertilizer application field, the yields of wheat and maize increased at a rate of 61.5 kg/hm2 and 26.8 kg/hm2 per year, separately. There was significant positive relationships between the amount of fertilizer and yield increase (yield in fertilized treatment – yield in unfertilized treatment). Path analysis of the relationship between fertilizer, soil fertility and crop yield confirmed that N fertilizer amount had significant direct effect on wheat yield. Phosphate fertilizer also had an important effect on the wheat and maize yield. In conclusion, crop yield in Drab Fluvo-aquic soil decreased slowly under no fertilizer condition, increased slowly under fertilizer treatment.