Emergy analysis of paddy farming in Hunan Province, China: A new perspective on sustainable development of agriculture

The multi-functionality of paddy farming has become a hot issue recently. Paddy farming provides numerous ecosystem services that are crucial to human well-being. However, evaluation of the contribution of paddy farming to human well-being usually focus on its economic value, while its non-market services are usually ignored. Only evaluating the market profits or market relative benefits cannot reflect comprehensively the contribution of paddy farming to people's well-being. This will affect people's choices for or against paddy farming activities and people's opt for invest or not invest in it. A comprehensive evaluation of paddy farming can provide an important reference for the government and society to conserve the multi-functionality of paddy farming and achieve sustainable development. To this end, this paper reports a case evaluation of paddy farming in Hunan, the largest rice producing as well as rice yield province in China, and uses emergy theory to make a comprehensive evaluation for paddy farming. The emergy evaluation results of the paddy ecosystem in Hunan are as follows: in 2010, the input emergy of the paddy ecosystem in Hunan is 2.51E+22 sej and the output emergy is 6.31E+22 sej. For the input emergy, the part from natural resources is 1.96E+21 sej and the part from human society is 2.32E+22 sej; for the output emergy, the part from products is 2.22E+22 sej, the part from impositive externality is 4.16E+22 sej and the part from negative externality is −7.41E+20 sej. Taking the non-market outputs into consideration, the gains from the human economic society's 1 $ input in paddy farming, emergy sustainability index (ESI) and emergy profit rate are respectively 2.73 $, 3.53 and 151.31%. If the evaluation leave out the non-market output, the three indexes are only 0.96 $, 1.24 and 30.67%. The research results show that non-market services of paddy farming contribute significantly to human well-being. Therefore, in order to protect the multi-functionality of paddy farming and achieve the sustainable management, the government should take reasonable measures and make incentive plans.