Emergy Analysis and Assessment of Sustainability on the Agro-ecosystem in Heilongjiang Province: As a Case of Xinglong Town

Agriculture is the foundation of national economic development. Agricultural sustainable development is an important part of the social-economic sustainable development and a key historical task of building new socialist countryside in our country. Xinglong town is a typical representation of black cultivated land in Heilongjiang Province. This study presents an ecological analysis of the agro ecosystems of Xing long town for the period from 2005 to 2009, on the basis of Odum's well known concept of emergy in ecological economy. The results indicated that : there was an increasing trend in the total emergy input from 2005 to 2009, among which, purchased supplemented energy accounted for 69.4%, of which chemical fertilizer accounted for a larger proportion. And the proportion of environmental resource was 20.1%and that of renewable organic energy value were 6.8%. Depending on the purchased supplemental energy made the agro ecosystem withstand greater pressure on the environment and the environment load ratio of five-year growth. The net emergy yield ratio was higher than national average and showed a decreasing trend. The environment sustainable index (ESI) was 1.41, which indicated there had greater potential for sustainable development on the agro ecosystem in Xing long town, and showed a declining trend also. The variation of the indices was an obvious indicator for the transformation of agriculture in Xinglong town from traditional to modern pattern and the development of agro ecosystems need to be further improved.