A Study on the Spatial Heterogeneity of Grain Yield Per Hectare and Driving Factors Based on ESDA-GWR
利用ESDA和地理加权回归模型，分析中国31个省份每公顷粮食产量的空间差异及驱动因素，发现中西部地区增产潜力大，化肥边际收益递减，为区域粮食安全政策提供依据。
The regional difference of grain yield per hectare is very important for national food security in China,especially in the situation of limited arable land and rapid urbanization.Taking 31 provincical regiones as sampling unit in China,using the methods of ESDA and spatial analysis of GIS,and applying a spatially varying-coefficient based geographically weighted regression(GWR) model,the paper presents spatial heterogeneity of grain yield per hectare and driving factors according to difference in natural conditions and economic development types.The results showed that increase of grain yield per hectare in mid-west regions has a significant impact on grain productivity in China,because 75% of higher potential regions for yield increase are located in mid-west during 1999 to 2008.And there is a significant spatial correlation for grain yield per hectare in different regions,and there is a shift for the gravity center of grain yield per hectare from eastern to northern and western regions.Thd driving factors of different regions show a localization characteristic of no-stationary intercourse.The effect of additional application of fertilizer to grain per hectare exists larger difference because the coefficient estimations are all positive in 1999 and partially negative in 2006～2008,which indicated that some regions are in the phase of diminishing marginal returns for fertilizer.Therefore,effective measures should be adopted to ensure China's grain security according to present situation of grain yield per hectare and effect mechanism of driving factors.