Relation between summer maize yield and climatic condition in Shaanxi

The statistical methods such as the relation analysis,orthogonal polynomial integral regression are used to analyze the relation between the summer maize yield and the meteorological elements during 1971～2003.The results show that the climatic motion index of the summer maize is 0.167,which has 73.1% of the summer maize yield motion.The climatic yield has about 5 years of periodic motion.The precipitation of the last twenty days in June,the temperature of the last ten days in July,the precipitation of the middle ten days in August and the sunshine in September play an important role for the summer maize yield in Shaanxi.