| The field experiment about the optimum rates of applied fertilizers and the responding models of greenhouse cucumber to the fertilizers in the loess plateau coming across North Shaanxi province was carried out with the three-factor, five-level D-optimum repercussion layout for the use of N, P and organic fertilizers. In the experiment, the responding models of greenhouse cucumber to N, P and organic fertilizers were found out and the effects of N, P and organic fertilizers on greenhouse cucumber were explored. Of the three kinds of fertilizers, organic fertilizers had the strongest influence on the yield of greenhouse cucumber while P and N fertilizers had similar influences on the yield of greenhouse cucumber. With the rate of organic fertilizers rising up, the yield of greenhouse cucumber kept upward; P and N fertilizers increased the yield of greenhouse cucumber at the rates varying within certain limits beyond which, the yield would fall down. On the basis of the responding models of cucumber to N, P and organic fertilizers, an optimized fertilization plan of N, P and organic fertilizers, was put forward for the target yield of 83000～88000 kg/hm2, was as follows: N fertilizer 809.21313.1 kg/hm2, P 583.1～978.6 kg, organic fertilizer 64151.3 t/hm2 and 1 N∶0.72 P2O5. |