| Climate change has significantly influenced food production,and ensuring the stability of food production is based on the efficient and sustainable use of agricultural climate resources.This paper first uses the step-decreasing mechanism model to calculate the crop potential productivity of corn,rice,and wheat crops in Chinese major grain producing areas,and then decomposes the factors affecting crop potential productivity using the LMDI decomposition method.Furthermore,this paper analyzes the deviation of the center of actual productivity from crop potential productivity using the center of gravity shift model,and finally evaluate the climate resource utilization efficiency of actual productivity to crop potential productivity.The main conclusions are as follows:(1)From 1980 to 2018,the collation of average crop potential productivity in the major grain producing areas was corn(17368.93kg/hm~2),rice(16838.08kg/hm~2),wheat(12467.17kg/hm~2),from large to small.In terms of time changes,the potential productivity of corn has declined significantly,while the crop potential productivity of rice and wheat have increased significantly.In terms of spatial changes,the high-value areas of wheat crop potential productivity have expanded,the high-value areas and low-value areas of corn crop potential productivity have both shrunk,and the spatial structure of rice crop potential productivity has changed little.Therefore,ensuring food security requires a correct understanding of the temporal and spatial characteristics and trends of climate change.(2)The duration of sunshine in the major grain producing areas has been significantly reduced,and the light effect of crop potential productivity is negative;the temperature resource is significantly increased,and the temperature effect of crop potential productivity has a positive effect on rice and wheat,and a negative effect on corn;the fluctuating characteristics of the precipitation resources are not obvious,and the water effect of crop potential productivity is quite strong.Therefore,grain production should focus on moisture conditions.(3)From 1995 to 2018,the shifting distance of the center of gravity of the crop potential productivity in the major grain producing areas was smaller than the actual distance,and showed the characteristics of the same direction.The geographic centers of potential productivity of major food crops are all located to the south of the actual productivity,more detailly,corn and rice are located to the southwest,and wheat is located to the southeast.(4)The climate resources utilization ratio increased slowly.Besides,the climate resources utilization ratio of main grain crops were higher in the Huang-Huai-Hai agricultural region,Northeast agricultural region and Southwest agricultural region,while the climate resources utilization ratio in the middle and lower reaches of the Yangtze River agricultural region was lower.Therefore,we should adjust the focus of grain production and balance the level of resource utilization between north and south in China. |
