Dynamic Study And Comprehensive Evaluation On The Benefits Of The Land Conversion Project In Hongya County

Some ecological,economic and social benefits were obtained since the Land Conversion Project(LCP)was tried in 1999.As the project construction is pushing forward, the problem that evaluation the dynamic benefit of the LCP scientifically and reasonably is not only concerned by government and public,but also needed to research and solve at present.This paper is studied on the forest(bamboo)-grass reafforestation patterns and Hongya County,the benefits of the patterns and the influenced aspect of the LCP were analyzed,the dynamic of the comprehensive benefit evaluation_index systems of pattern and county were established,the dynamic comprehensive benefits were evaluated and forecasted,and the dynamic law and trend were summarized,in order to provide the theoretical and technical approach for evaluation the achievement of the LCP scientifically.The dynamic of the ecological and economic benefits of the two reafforestation patterns(Pleioblastus amarus-Hemarthria compressa and Betula luminifera-H,compressa) were studied.Total biomass,soil infiltration,water conservation capacity,total porosity,O₂ release amounts of were gradually increased,surface runoff,sediment losses and soil bulk density were reduced,but the varieties for P.amarus-H,compressa pattern showed not evident during after the 4^threafforestation year;vegetation carbon stored contents,soil organic carbon and total nitrogen contents descended sharply when canopy was not closed,then increased gradually with the canopy density's increasing.The previous pattern could attain higher incomes every year than farming land,but the later could obtain some economic incomes only from grass.Comprehensive benefit evaluation index systems of models were established that included 2 item layer such as ecological benefit and economic benefit,6 factor layer such as soil and water conservation,soil improvement,direct economic benefit and so on,and 12 indexes such as biomass,species diversity,surface runoff and so on,The pattern's dynamic comprehensive benefits were evaluated and forecasted using fuzzy comprehensive evaluation method and grey systems theory,the results demonstrated that system stability,soil and water conversation capability,and carbon stored function and O₂ release amount were gradually increasing,whereas they didn't change obviously after the fourth year for P.amarus-H,compressa pattern;the soil improvement effects didn't show obvious,however they had restored and increased trends;whole ecological-economic systems were heading for favorable circulation when ecological benefit,economic benefit and comprehensive benefit gradually increased.In addition,P.amarus-H,compressa pattern could be popularized locally because of its higher comprehensive benefit.Ecological,economic and social dynamic benefits of Hongya County were studied during the LCP.After the LCP's construction,Eco-environment was improved,rural economy was developed and social life quality was boosted.Until 2007,the total biomass was 90.62×10⁴t,sediment losses were 0.36×10⁸m³,water conservation content was 866.88×10⁴t,CO₂ stored contents were 212.37×10⁴t,and O₂ release amounts were 116.24×10⁴t,and direct incomes was 6.96×10⁸Yuan from the reafforestation land.In addition,the project promoted the increase of agricultural production value,livestock industry production value and farmer incomes,arranged the enough labors and improved agriculture industrial structure.Comprehensive benefit evaluation indexes systems of whole county were established that included 3 item layer and 7 factor layer and 12 index such as reafforestation area, water conversation content,sediment losses content,livestock industry production value and rural employment rate and so on.The dynamic comprehensive benefits of Hongya County were evaluated and forecasted.The ecological,economic,social and comprehensive benefit presented ascending situations,ecological benefits were playing role in the comprehensive benefits, and eco-social benefits were lagging behind,but the benefits and the relationship among different benefits would be increased and developed.Lastly,according to the previous analysis,sustainable development measurements of the LCP were put forward such as optimizing tree species structure,optimizing and controlling models,boosting local industrial development as well as improving labor quality and so on.