黄土高原沟壑区退耕还林典型优化模式机理分析

以退耕还林工程重点地区的黄土高原沟壑区为研究对象，引入系统动力学理论和技术。采取试验站点观测与广泛调研集成等5个结合的技术路线，横跨自然、经济、社会科学三大领域，共获取原始数据10000多个，对黄河中游黄土高原沟壑区山西省乡宁县试验点退耕还林生态一经济一社会效益最优结合、可持续发展的油松X侧柏X花椒X刺槐优化模式的作用机理，从生态、经济、社会效益及其相互作用等方面进行了分析研究．结果表明，该模式的生态、经济和社会效益各主要指标均处于最佳或较好状态；三大效益综合比较，该模式是最佳模式；经F检验，该模式与其它模式均呈极显著性差异．

Mechanism analysis of optimized model of conversion from farmland to forestland in the hill-gully sub-region of Loess Plateau

Conversion from Farmland to Forestland Program (CFF) is one of the six great ecological forest programs in China.This study covered the CFF model area of the hilly-gully sub-region of loess plateau,and introduced system dynamics and other latest theories and methodologies.Based on the analysis of five modules including that of the site observation of field stations and extensive investigations,and over 10 000 original data obtained in the fields of natural science,social science and economics,the operational mechanism of the optimized model was studied.The optimized operational models integrated maximized ecological,economic and social benefits,while sustainability concepts were proposed for typical CFF sites:The Pinus tabulaeformis Platycladus orientalis Zanthoxylum spp. Robinia pseudoacacia model at the eroded flat ridges of the middle reaches of the Yellow River.The result showed that the ecological,economic and social benefits of the optimized model reflected by main indexes were the best or better,and in the other models,either individual one was the best or others were not.From the viewpoint of comprehensive comparison of three great benefits,the optimized model was most excellent,and had eminent difference comparing to other ones through F test.The relationship between ecological and social benefit was eminent positive correlative.Social benefit was the same with economical one at some degrees.The relationship between ecological and economical benefit was more complicated.On the whole,they were positive correlative,but the economical benefit was not the greatest when the ecological one was the greatest.In general,from the viewpoint of largest comprehensive benefit,the three great benefits were not all the best,indicating that the combination of the modules must be reasonable.In order to achieve the ultimate goal of CFF,we must choose the optimized combination of ecological,economical and social benefits,and can't only pursue any one maximum of three great benefits.