This study has been completed in the Old Town of Luochuan County, Shaanxi Province from March 2008 to October 2008. 12-year-old apple (Malus pumila cv. FuJi) tree in the full fruit was taken as the material in this experiment, and was fertilized with the N P K before germination.. In order to reduce the scale of the experiment, we used an optimized design with Quadratic regression orthogonal in which there were three factors, five levels, a total of 15 treatments. Taking the largest yield as the exp...