Abstract:

This study is based on the statistical data of agricultural grain production in the Guanzhong region of Shaanxi Province,China from 1978 to 2017.This paper discusses the changing trends of agricultural grain production in the Guanzhong region from 1978 to 2017.In addition,this study analyzed the factors influencing grain production from 1978 to 2017 by means of principal component analysis (PCA).The main results of the analysis and research are summarized below.First,the trend change of agricultural grain production in the Guanzhong region shows a cyclical growth pattern with a cycle of 3-7  and the average growth rate of grain production in each cycle is 4.5%.The grain production process is manifested as a series of continuous “large valleys” or “large peaks” with high-yield years and low-yield years occurring successively,thus causing the grain yield to be extremely unstable.Second,the statistical data for agricultural production were calculated and analyzed by a PCA model.The cumulative variance contribution rate was greater than the 0.85 standard and there were three main components that had greater impacts on grain production.The first principal component factors are all geographical factors and the variance contribution rate reached 0.55;this indicates a very significant and decisive role on agricultural grain production in the Guanzhong region and is the most basic condition for guaranteeing grain production in Guanzhong.The main components include the farmland areas affected by disasters (excluding diseases and pests),areas cultivated with major food crops,areas of farmland affected by disasters (excluding diseases and pests),and effective areas of irrigated farmland and cultivated areas.The second principal component,with a cumulative variance of 0.25,is an important factor affecting grain production and vital supply for agricultural production in Guanzhong.In addition to the areas of farmland with stable grain production based on geographical factors,the index of input factors of production materials and the labor force such as agricultural electricity consumption,chemical fertilizers,and agricultural machinery are included.The third principal component is pesticide application,with a cumulative variance of 0.068,which exhibited little effect.The actual cumulative variance contribution rate of the three principal components is 0.87.

Key words: agriculture in Guanzhong, geographical factors, production inputs, cycle, principal component analysis