Fertilizer use efficiency of maize and soybean in the center of black soil zone

Fertilization plays a critical role in supporting crop yield under the decrease of soil fertility capacity.Large amount of fertilizer application and degraded soil fertility are both responses for the relative low fertilizer use efficiency (FUE), FUE of cultivated soil received balanced fertilization is not still clear.We established a field experiment in the center of black soil zone after three years of straw return, including balanced fertilization (NPK) and nutritional deficiency (NP, NK and PK) treatments The results showed that the yield of maize and soybean with NPK treatment was significantly higher than NK and PK treatments respectively, while no significant difference was found between NPK and NP treatments; and the response of maize and soybean yield to fertilizer was in an order of N>P>K, indicating that N and P were both the main factors impacting crop yield.N, P, and K fertilizer use efficiencies of maize were 38.8%, 23.9% and 44.2%; N, P, and K fertilizer use efficiencies of soybean were 40.8%, 29.1% and 38.3%, respectively.Fertilizer agronomic use efficiency, response of yield and relative yield in this study would provide the necessary parameters for local crop nutrient expert system.