Cropland Contribution Index Based on the Regional Cropland-Grain-Population Relationship

In order to reveal the attribute clearly and to understand the situation of the regional cropland-grain-population relationship,this paper presents the "cropland contribution index" model,and divides the cropland contribution land index into four levels,that is below subsistence,subsistence,well-off,and richness.Then,it analyzes the whole China,13 main producing regions,11 grain balancing regions,and 7 main sales regions.Results show that the overall cropland contribution index presented a rising trend in 1949 to 2010,it once reached well-off level in 1996 to 1999,and it reached the well-off level again in 2010,but there is still a long way to reach the level of richness.The cropland contribution index is relatively high in main producing regions.In 2010,all main producing regions reached the well-off level,and some provinces even reached the richness level.However,the cropland contribution index of main sales regions is lower and takes on a downtrend,especially in Guangdong,Zhejiang,and Fujian provinces.The cropland contribution index in grain balancing regions is not high,and most provinces are still at subsistence level.Researches have indicated that the cropland contribution index can simply and rapidly reflect the relation between regional cropland,grain and population.