旱地农田肥水耦合效应及其模式研究

By referring to Wallance's MFYP curve and the result of previous experiment, this paper put forward a model of applying fertilizer on dryland, and analyse the interaction among N, P and water. The result of experiment show that: under the condition of higher soil water content before sowing, the interaction between N and P , P and water are Liebig synergistic type, but N and water is synergistic type; when applying N,P and water at the same time, the interaction is sequentially additive type, and they become Mitscherlish limitation factor. Under certain condition, the type of interaction for different factors can transform with each other. The response of N increases with the increment of soil water, but the response of P decreases with the increment of soil water.