Abstract:Through a 15-year field monitoring location experiment, the nutrients supplying characteristics of yellow fluvo-aquic soil and their changes in the different fertilization systems were studied. The results indicated that fertilizer structure affected greatly crop yields. Under the rotation system of wheat and maize, the average yields of various treatments were in the order of MNPK > MNP > MN > NPK > NP > N > M > CK. The soil without application of fertilizer in the long-term rotation was poor in the nutrients supplying ability, thus resulting in the decreasing of crop yields year by year. The contribution rate of soil basic fertility and fertilizers to crop yields arveraged 37.2% and 62.8%, respectively. In the contribution of fertilizers to crop yield, 25.2% was attributed to organic manure and 74.8% to chemical fertilizers in which N, P and K fertilizers accounted for 64.6%, 27.2% and 8.2%, respectively. Organic manure played an important role in improving soil fertility, improved the soil physical properties and enhanced the adverse resistance and steady high yields of crops. The soil available K deficiency appeared in all of the fertilization treatments. So, attention must be paid to the applying of potash fertilizer so as to maintain potassium balance in the soil.