摘要
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.