Abstract: This paper deals with the interaction between chemical Nand organic fertilizers in high-yield wheat/corn farmland ecosystem, and developed a safe and rational Napplication rate.The typical cropping system is winter wheat intercropped with summer corn. In the field experiment, four rates of urea and three levels of poultry manure were applied and split-plot experiment design was used, in which the manure treatments were placed as the main plots and the urea treatments as sub-plots. Phosphate and potassium fertilizers were same for all plots. The result shows that the interaction between chemical nitrogen fertilizer and poultry manure is significantly negative, and the safe and rational Napplication rate in high yield winter wheat summer corn system was 300kg·hm^-2yr^-1 and 150kg·hm^-2, respectively.

Key words: Winter wheat, Summer corn, High-yield farm ecosystem, Nitrogen, Rational regulation, correlation coefficient, dependence, hydrological variability, auto-regression model, stochastic process.