Spatial-temporal Variation Characteristics of Grain Yield per Unit Area and its Balanced Increasing Potential in China

The aim of this study is to provide assistance decision for grain yield in China, which can provide basis for reasonable layout of grain production project. Based on the statistical data of 2301 counties in China, using spatial autocorrelation analysis method, spatial changes of grain yield per unit area at county level in China during 1990-2010 were discussed and then the increase potential of grain yield per hectare and total yield at regional scale were calculated. The results showed that: (1) Grain yield per unit area at county level showed the evident pattern “High in the northern while low in the southern” and “High in the eastern and western while low in the middle”; The average grain yield per hectare increased by 1040.74 kg/hm2 during 1990-2010 and the increment of grain yield per unit area descended from North to South at county level. (2) Grain yield per unit area at county level in China had a strong spatial autocorrelation. The counties with "High-High" and "Low-Low" correlation were the majority. Counties with significant "High-High" correlation in 2010 were mostly located in plain area, while counties with significant "Low-Low" correlation were mainly distributed in Hengduan Mountainous Area, Inner Mongolia steppe Area, etc. (3) Two thousand three hundred and one counties were divided into 41 first-grade regions and 115 sec- grade regions according to the coupled conditions of cultivation system regionalization and LISA cluster map. The total potential output of China was 1.77×108 tons.