Application of traditional ecological footprint and its derivatives in evaluating utilization of croplands

Cropland is a public resource with important functions such as ensuring food security, offsetting the demands of industrialization and urbanization and balancing ecological requirements by returning farmlands to forests and grasslands. Based on emergy theory analysis, two modified ecological footprint accounting models regional emergetic ecological footprint (REMF) and cropland emergetic ecological footprint (EMEF) and the traditional ecological footprint model were used to evaluate utilization of croplands in Xinjiang. The merits and demerits of the three models were also determined. The study shows rising ecological footprint of cropland for per-capita in Xinjiang in 1978~2007. Per-capita ecological capacity in the study area is stable, indicating a marked decline in sustainable ecological development index (ESI) in the region. EMEF also shows an unsustainable use of croplands in Xinjiang for 2001~2007, following a sustainable use in 1978~2000, with ESI dropping from 5.63 in 1978 to 0.60 in 2007. Comparative studies of the three methods show that the regional emergy ecological footprint model (which is only a general analysis of regional sustainability) is not suitable for evaluating use of croplands. Cropland emergy ecological footprint model is the best as it takes into account of sustainability of croplands and to some extent overcomes the shortcomings of traditional ecological footprint model.