Emergy Analysis of the Land Use Practices in West Jilin Province, a Typical Area of the Agro-pastoral Transition Zone in Northern China

Land use practices were identified based on emergy accounting method in 1986, 1996 and 2004 for West Jilin province (WJLP), a typical area of the agro-pastoral transition zone (APTZ) in northern China. Input and output flows, and various emergy based indicators were calculated for the integrated agro-pastoral system and its subsystems. The results show that the emergy investment ratio (EIR) and environmental loading ratio (ELR) present an increasing tendency and the environmental sustainable index (ESI) keeps decrease with a fluctuating emergy yield ratio (EYR). However, the variation of emergy indicators illustrates that the long term land use practice of West Jilin Province, alienation too much grassland to cultivated land, heavy reliance on nonrenewable resources and over cultivation and overgrazing, is a deviation from the ultimate goal of sustainability. The increasing growth of agro-pastoral production, especially the rapid expansion of the ago-subsystem is an inappropriate choice for the unfavorable climate, higher resources requirement, and higher environmental cost. Therefore, pastoral subsystem could buffer from some adverse impacts of the frangible environment and contributed greatly to improve the agro-pastoral coupling, but only on the important precondition to keep livestock consistent to the ecological carrying capacity. Several countermeasures have been discussed for future land use management based on the emergy results.