【作者】 袁泉；

【导师】 廖允成；

【作者基本信息】 西北农林科技大学 ， 生态学， 2008， 硕士

【摘要】 毛乌素沙地地处我国北方农牧交错带,农牧交错带作为农耕区与草原牧区相连接的半干旱生态过渡区是一个非常典型的生态脆弱区,属于一个相对独立的自然-社会-经济的复合生态系统类型,既是我国主要大江大河的水源涵养地,也是遏制沙漠化,沙化东移和南下的屏障。开展该区的研究对促进农牧交错带农业可持续发展,对农业生产,生态环境改善、国民经济持续发展以及社会稳定、民族团结有着重要的意义,在我国经济、社会发展和环境保护方面具有重要的战略地位。本文采用层次分析法对毛乌素沙地农业生态系统进行了环境脆弱度评价,全面分析了毛乌素沙地农业生态系统的环境脆弱性变化特征,建立了脆弱度评价模型。提出了毛乌素沙地脆弱农业生态系统改良优化模式,分别是种植业子系统优化模式—节水型种植结构模式,畜牧业子系统优化模式—节粮型畜牧结构模式,林业子系统优化模式—生态型防护与恢复结构模式。通过分析研究得出以下结论:1.选择毛乌素沙区11个旗、县为评价单元,建立一套毛乌素沙地农业生态系统环境脆弱度评价的指标体系,共包括降水量、蒸发量、有效积温、沙漠化程度、人口数、人均农业产值、人均工业产值、等11项指标值,运用层次分析法确定指标权重,建立毛乌素沙地农业生态系统环境脆弱度评价模型,通过评价得出11个旗、县的脆弱度排序为:鄂托克旗>定边>乌审旗>伊金霍洛旗>鄂托克前旗>盐池>靖边>榆阳>神木>横山>府谷,基本上是西北部脆弱度高,而东南部脆弱度低。2.该区沙漠化严重,并有着明显的地区差异。近年来,沙地总面积增加,固定沙地转化为半固定沙地和流动沙地速度加快,流动沙地占主要地位。沙漠化扩展趋势明显,鄂托克旗、定边县、乌审旗、伊金霍洛旗、鄂托克前旗、盐池县、靖边县、榆阳区的沙漠化比较严重,而府谷、神木,横山的沙漠化相对较轻。3.该区农牧业人口比重较大,耕地面积逐渐减少,单位土地面积的载畜量增大,经济发展较大地依赖于农牧业,经济的脆弱性较大。耕地面积占沙地总面积和人均量大幅度减少,产业结构较单一,农业发展过度依赖于种植业和畜牧业。4.提出了毛乌素沙地脆弱农业生态系统良性循环机制:政策法规支持机制,工程技术引导与支撑机制,资金保障机制,人口控制及人口素质提高机制。5.提出了毛乌素沙地脆弱农业生态系统改良优化模式:(1)种植业子系统优化模式——节水型种植结构模式;(2)畜牧业子系统优化模式——节粮型畜牧结构模式;(3)林业子系统优化模式——生态型防护与恢复结构模式。更多还原

【Abstract】 The Mu Us Desert was located in farming-pastoral zone of northern china, a very typical ecological fragile region, which was effected by human activity greatly. It was represented to a great extent many typical problems about the relationship between human activity in semi-arid, aid desert area and natural environment. Research on change of natural environment and effect of human was very meaningful to prevention of land desertification in farming-pastoral zone of northern china, our national ecological environment and regional development trans-province (zone).This research was adopted the analysis hierarchy process in assessment of environmental vulnerability in Mu Us Desert agroecosystem, a comprehensive analysis on variation characteristics of environmental vulnerability in Mu Us Desert agroecosystem was analyzed, a vulnerable degree assessment model was estabilished. And optimized models of improving fragile agroecosystem in Mu Us Desert were proposed, there were an optimized model on planting subsystem—a structure model of water-saving planting; an optimized model on animal husbandry husbandry system—a structure model of grain-saving animal husbandry and an optimized model on forestry subsystem—an ecological structure model of restoration and reconstruction. The main conclusions were as follows.1. The eleven counties(banners) of Mu Us Desert are chosen as appraisal units. A set of indexed system was set up for appraising environmental vulnerable degree, 11 indexes value including precipitation, evaporation, annual mean temperature, desertification degree, population, average agricultural output value, average industrial output value and so on. The weight of environmental vulnerable degree of each model was set up, the result of assessment was that the order of vulnerable degree of 11 counties(banners) from large to small was Etuoke banner>Dingbian>Wushen town>Yijinhuoluo town>Etuokeqian banner>Yanchi> Jinbian>Yuyang>Shenmu>Hengshan>Fugu. Vulnerable degree of northwest was high and that of southeast was low basically.2. Desertification was serious in this area and there was existed apparent regional difference. The total area of Mu Us Desert was increased, the growth rate of shifting sandy and fixed sandy land was quicker, shifting sandy land was dominated absolutely and the extending trend of desertation was very obvious; desertification of Etuoke town, Dingbian county, Wushen banner, Yijinhuoluo town, Etuokeqian banner, Yanchi county, Jinbian county and Yuyang region was serious and that of Fugu and Jia County was slighter relatively.3. The proportion of farmer population was large, the cultivated area of that region was incessantly decreased and the grazing capacity of unit land area was increased. Economic development was depended on farming to a great degree and vulnerability of economy was large. Cultivated land area totally and per capital was reduced in large range, estate structure was monotonous and agricultural development was depended on farming excessively.4. Optimized models of improving fragile agroecosystem in Mu Us Desert were proposed: supporting mechanism of policies and regulations, engineering technological guide and supporting mechanism, guarantee mechanism of fund, improving mechanism of population control and population quality.5. Optimized models on restoration and reconstruction of fragile agroecosystem in Mu Us Desert was proposed:(1) an optimized model on planting subsystem—a structure model of water-saving planting(2) an optimized model on animal husbandry husbandry system—a structure model of grain-saving animal husbandry.(3) an optimized model on forestry subsystem—an ecological structure model of restoration and reconstruction.更多还原