The study of effect of water and fertilizer is the inevitable course for dry land agricultural sustainable development. This paper has studied the growth, development, tree nutrition and soil fertilizer efficiency of apples grown on Loess Plateau slope by the three-factor, four-level D-optimum repercussion for the use of N,P and K under different water conditions, and the conclusions are as follow:
1. The growth index of apple tree under supplementary irrigation is better than non-irrigation. ...