基于能值分析的高台县农田生态系统可持续发展评价

Evalution of sustainability for farmland ecosystem of Gaotai County based on emergy analysis

应用能值分析理论和方法,选取1997—2012年的数据,对高台县农田生态系统投入产出结构和能值指标进行了分析,并运用主成分分析法对高台农田生态系统进行了综合分析。结果表明,高台县农田生态系统能值投入呈现整体增加、局部时间段减小态势,1998年能值投入值最小,为325×10^(18)sej,2012年投入值最大,为496.89×10^(18)sej,主要原因是工业辅助能的增加最明显,从1997年的180.98×10^(18)sej增加到2012年285.14×10^(18)sej。总的能值产出波动较大,2002年最小,为240.37×10^(18)sej,2012年最大,为473.37×10^(18)sej。环境负载率总体呈上升趋势,由1997年1.11上升到2001年1.54,再降至2012年的1.39。2002年可持续指数为0.53,远低于2001全国平均水平(1.23)。总的来说,高台县绿洲农田生态系统的综合水平总体上呈现下降趋势,16年来研究区综合水平差异大,1997—1999年生态系统综合水平较高,2000—2006年环境恶化,2007—2009年生态环境有所改善,2010—2012年高台县绿洲农田生态系统的可持续发展状况恶化。因此,高台县在未来发展过程中应该合理调整种植业结构,合理开采利用水资源,保护耕地,积极引进先进机械、技术,提高农业机械化水平,促进高台县经济社会可持续发展。

Input and output structure and emergy indexes of the farmland ecosystem in Gaotai were investigated using the theory of emergy analysis and principal component analysis. The results indicated that total emergy input of the oasis farmland system in Gaotai County was overall increased,whereas went decreased in certain period.The lowest input value was 325 × 10（18） sej in 1998,while it reached a maixium of 496. 89 × 10（18） sej in 2012,mainly due to obvious increase of industrial emergy that changed from 180. 98 × 10（18） sej to 285. 14 × 10（18） sej. Emergy output exhibited a marked fluctuation pattern. It reached a minimum of 240. 37 × 10（18） sej in 2002 and a maximium of473. 37 × 10（18） sej in 2012. Agricultural oasis ecosystem environment load rate was high and it became elevated from1. 11 in 1997 to 1. 54 in 2001,and was then dropped to 1. 39 in 2012. Sustainable development index of farmland in Gaotai oasis ecosystem was 0. 53,which was lower than the national average level of 1. 23 in 2001. Generally speaking,the comprehensive level of the ecosystem in Gaotai area was getting worse,dispaying strong variations during recent 16 years. The ecosystem was good from 1997 to 1999 in Gaotai,while the environment problems became crucial from 2000 to 2006. Though it had been improved from 2007 to 2009,in recent years,the sustainable development of oasis farmland ecosystem continued to be cruel. Agriculture is the basis for the development of Gaotai. Therefore,adjustment of the planting structure,rational exploration for water resources,protection on arable land,and active introducion of advanced machinery and technology should be implemented in the future to promote economic and social development.