%0 Journal Article
%T Emergy Analysis of Agroecosystem Productivity of Typical Valley in Loess Hilly-gully Region of the Loess Plateau: A Case Study in Zhifanggou Valley of Ansai County<br>黄土高原典型流域农业生态系统生产力的能值分析——以安塞县纸坊沟流域为例
%A DONG Xiaobin
%A GAO Wangsheng
%A YAN Maochao
%A <br>董孝斌
%A 高旺盛
%A 严茂超
%J 地理学报
%D 2004
%I 
%X Using data from Zhifanggou valley of fragile loess hilly-gully region, this paper studied the feature of primary plant productivity, secondary animal productivity, economic productivity of farmers and ecosystem service productivity as well as the relationships among them based on the emergy analysis method. The result showed that the primary productivity of Zhifanggou valley had been improved considerably after twenty years harnessing practices. Consequently, vegetation cover increased to some extent and the great ecosystem services created the base for the formation of the agroecosystem productivity. On the whole, however, the valley was still in the state of lower emergy input, lower coupling degree and lower energy efficiency. They are mainly reflected in the non-obvious coupling effect among various systems and the existence of the lower emergy value of the secondary aminal production. The emergy of primary production could not be transformed into the emergy of the animal production which meant that the capability of transformation from the primary production to the secondary production was lower. The irrational planting structure led to the lower capability of transformation from potential economic value of product emergy to actual economic income of the farmers. So, it is really necessary to adjust the industrial structure and allocation in order to promote the inversion among the agroecosystem productivities.
%K emergy
%K ecosystem productivity
%K loess hilly-gully region<br>能值分析
%K 农业生态系统生产力
%K 黄土高原丘陵沟壑区
%U http://www.alljournals.cn/get_abstract_url.aspx?pcid=E62459D214FD64A3C8082E4ED1ABABED5711027BBBDDD35B&cid=869B153A4C6B5B85&jid=F7B5B947C24B9D649491012214E4BEF4&aid=DAE788145620A6B9&yid=D0E58B75BFD8E51C&vid=6AC2A205FBB0EF23&iid=0B39A22176CE99FB&sid=E089FDF3CDAE8561&eid=F8035C8B7D8A4264&journal_id=0375-5444&journal_name=地理学报&referenced_num=25&reference_num=47