Regional Differ ence of Ecological Footpr ints of Cropland in J iangsu Province Based on Emergy Analysis
基于能值分析的江苏省耕地生态足迹区域差异

Some scholars have calculated ecological footprint using the theory of emergy analysis.But there are some drawbacks in their studies.This paper singles out the ecological footprint of cropland from 6 types of land use as study topic focusing on the regional differences in Jiangsu province,revises the ecological carrying capacity with productivity factor because land use efficiencies vary across regions,and uses ecological gap index(EGI) in place of ecological deficit or remainder to evaluate the ecological sustainability.In the research of ecological carrying capacity of cropland,the solar radiation,precipitation,soil fertility,the efficiency of land use and area of cropland are considered as natures of ecological carrying capacity,and a new concept of "standard area" is established in terms of the quality class of cropland.In Jiangsu province,ecological carrying capacity of cropland in northern region is more than that in the middle and southern regions,that is,Yancheng,Huaian and Suqian have the highest ones while those Wuxi,Nanjing and Suzhou are the lowest.Ecological footprint of cropland in southern region is less than that in the middle and northern regions,that is,Yancheng,Nantong and Huaian have the greatest ones while those Wuxi,Suzhou and Changzhou are the least.Ecological gap indexes of cropland of all 13 regions in Jiangsu are all lower than 0.5,which means croplands usees are unsustainable.Cropland's EGI in the middle part is lower compared with southern and northern parts,and the midst is better than the eastern and western districts in Jiangsu's middle part.Suzhou and Wuxi have the highest EGI,and that Nantong and Yancheng have the lowest EGI.The results can be helpful for integrating the theory of emergy analysis to the conventional model of ecological footprint and for sustainable use of cropland in this province.