基于能值理论的水土保持生态效应评价——以山西省长治市为例

运用能值理论分析方法,选取2004-2014年的统计数据,对长治市水土流失治理生态经济系统的投入产出能值及主要能值指标进行分析.研究表明:系统能值投入波动较大,整体呈增加趋势,最低值为2008年的3.91×1021sej,最高值为2011年的4.33 ×1021 sej;系统总能值产出呈现整体增加、局部时间段下降趋势,最低值为2010年的5.95 ×1021sej,最高值为2014年的7.62 ×1021sej,其中2大主导产业中畜牧业整体呈增加趋势、农业中蔬菜产量不断增加都说明水土保持措施取得了一定成效;主要能值指标中,净能值产出率均＞1、可持续发展指数1＜ESI＜ 10,说明长治市水土保持措施的合理性与可持续性.能值理论分析表明,长治市水土流失治理生态经济系统的综合水平总体上呈现上升趋势,系统可持续发展状态良好,生态和经济向着平衡方向发展.

Analysis of the ecological effects of soil and water conservation based on emergy theory:A case study of Changzhi City of Shanxi Province

[Background] At present,the methods of ecological effects of soil and water conservation are usually dispersed in the evaluation of the ecological system and economic system.Since two methods of evaluation and measurement are different,it is difficult to compare them.Thus it is very necessary to evaluate the ecological effects of soil and water conservation by unifying measurement units.Emergy theory is based on the solar energy,which combines the ecological system and economic system,and unifies the unit of measurement.In this way,that can overcome the difficulties from the separation of ecological and economic systems.So far,the application of emergy theory in the evaluation of ecoeconomic effects of soil and water conservation has not been reported.[Methods] Based on the theory of emergy analysis and statistical yearbooks as well as other related information of Changzhi City from 2004 to 2014,we analyzed the emergy indexes of input and output of the soil and water losses control ecoeconomic system in Changzhi City.By analyzing and calculating,the different materials and energy were converted into the same standard emergy.Then the analysis tables of input and output of soil and water losses control eco-economic system as well as the emergy analysis index system in Changzhi City were established for analyzing and comparing the input-output emergy values.They were used for the assessment of soil and water conservation ecological effects in Changzhi and providing theory basis for the further soil and water losses control.[Results] The results showed that the emergy input of the water loss and soil erosion control eco-economic system was large and the overall trend was increasing.The lowest value was 3.91 × 1021 sej in 2008,the highest value was 4.33 × 1021 sej in 2011.Emergy input of the water loss and soil erosion control eco-economic system in Changzhi City was overall increasing,and the local time period declined.The lowest input value was 5.95 × 102~ sej in 2010,and the highest value was 7.62 × 102~sej in 2014.The total emergy of stockbreeding and vegetable production in agriculture overall increased,indicating that soil and water conservation measures have achieved some success.When the structure of the total emergy output was healthy,the net emergy output ratio both were greater than 1 and sustainable development index was in a reasonable range,indicating that the soil and water conservation measures in Changzhi City were rational and sustainable.[Conculsions] Generally speaking,the comprehensive level of the water loss and soil erosion control eco-economic system in Changzhi City is getting better and the sustainable development eco-economic system showed that the project's ecological and economic purpose was basically fulfilled.In order to maximize the ecological effect of soil and water conservation in Changzhi City,we should clear the direction of governance and zoning,deepen the reform of land,speed up the scale and intensive production,and strengthen the supervision and enforcement of soil and water conservation.