| It is the critical period to deepen the reform and accelerate transformation of the pattern of economic development from 2010 to 2015.With the Synchronous promote of industrialization,urbanization and agricultural modernization,the contradiction between supply and demand of land resources become more and more prominent.At the same time,farmland protection and economical and intensive use of land became a difficult task.Land consolidation has become an important mean of optimizing land use structure,improving the economical and intensive user of land,promoting protection of cultivated land.It also played a significant role in balancing urban and rural development,implementing land management system,achieving sustainable development.Land consolidation started in China late,our country land consolidation research focus on service in planning tasks and engineering construction.The research achievements were more focus on the comprehensive planning,analysis of potential evaluation,engineering technology,performance,etc,but the related ecological effect research relative lag.Some ecological problems occurred in land consolidation project areas,including soil erosion,soil harden,habitats degraded and the decrease of the biodiversity.Therefore,study the ecological effect of land consolidation is especially important.The ability transforming different types of resources in physical,energy and capital into a unified standard-emergy makes emergy synthesis become an appropriate tool for evaluating structural ecological-economic benefit.Previous studies have examined the effectiveness of emergy in varies of fields,but emergy synthesis has rarely been applied in cropland ecosystem located in land consolidation project area.Time scale is significant in the research,because the balance of the cropland ecosystem was destroyed first,then slowly formed a new equilibrium and remained stable during the construction and use of project.In this paper we studied the impact of land consolidation on cropland ecosystem from two time scales of the year and full life-cycle.Land consolidation activities,regarded as suddenly short-term external interference for the project area cropland ecosystem,influenced the system’s physical circulation and energy metabolism.Based on typical diagram of farmland ecosystem of ecological flow,combining with the specific characters of land consolidation,an analysis framework was built to reflect ecological flow direction and path in project area cropland ecosystem,and seven emergy indicators was used to evaluate the ecological effectiveness.Based on the framework and indicators,net emergy,emdollar value,emergy self-sufficiency ratio,emergy investment ratio,net emergy yield ratio,environment load ratio and emergy sustainable indices were analyzed before and after land consolidation activities from emergy input and output in Yixing land consolidation project area of Jiangsu province.The results were shown as follows:(1)Analysis from the perspective of the process on an annual time scale showed that:Affected by project construction,the cropland ecosystem reached a new steady state,which is a much better level than before,in the first five years after project completion.(2)Analysis from the full life-cycle of land consolidation showed that:(a)The project was expected to bring 2.04E+20sej ecological surplus and 97million dollars loss of emdollar value,causing the ecosystem own stability and macro-economic value decline.(b)The land consolidation led to self-sufficiency decline in the cropland ecosystem,at the same time,enhanced the dependence on economic investment.(c)Land consolidation reduced net emergy yield ratio and emergy sustainable indices,meanwhile,increased the environment load ratio.The sustainable development of cropland ecosystem located in land consolidation area declined. |
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