【作者】 李文忠；

【导师】 周心澄；

【作者基本信息】 北京林业大学 ， 水土保持与荒漠化防治， 2005， 博士

【摘要】 退耕还林是一项长期的、复杂的生态工程,其目的是为了恢复植被,减少水土流失,防沙治沙,改善日益恶化的生态环境,调整农村产业结构,增加农民收入。随着退耕还林工程全面实施,诸多相关理论和技术成为当今学术界研究的重点内容。然而,纵观国内外有关退耕还林工程研究现状,发现现有的研究多集中于退耕还林具体技术和政策措施等方面,而对退耕还林工程的优化配置模式和生态服务功能的综合评价缺乏系统性研究。为此,本文以恢复生态学的基本原理和可持续发展等理论为依据,系统地研究了青海省大通县退耕还林不同配置模式的生态功能,筛选出优化配置模式,为科学指导西部地区退耕还林工程建设,提高退耕还林生态效益和加快西部生态环境改善,提供理论依据和科学方法。同时对实现我国林业生态可持续发展,具有十分重要的理论和实践意义。 本研究以我国退耕还林工程科技试验县—青海省大通县为研究对象,在系统分析该县的产业结构、土地利用现状和立地类型基础上,分别在浅山区和脑山区的不同立地类型上各选择了5种退耕还林配置模式,进行了大量野外调查观测和室内实验测试,并用相关分析、因子分析、综合评价模型等方法系统地分析了退耕还林不同配置模式的水文效应、土壤质量、物种多样性和生产力影响,并进行了生态功能综合评价。得出以下主要结论: 1)在浅山区,林分总蓄水量以模式C(青杨+枸杞)的最大,为329.07mm;土壤总孔隙度、稳渗速率、结构系数以模式A(川赤芍)的最大,分别为56.78%、4.8mm/min、97.61%;土壤全N、水解N、速效P、速效K、有机质平均含量以模式C(青杨+枸杞)的最高,土壤养分状况最好;土壤抗冲性指数以模式D(中国沙棘)的最大,为1.136s/g;群落物种多样性指数以模式C(青杨+枸杞)的最高,为5.3091;群落总生产力以模式D(中国沙棘)的最大,为9.36t/(hm~2a)。通过对退耕还林不同配置模式的土壤持水量、团聚度、有机质含量、水解氮、速效磷、速效钾、物种多样性指数、均匀度等18个生态功能指标的综合评价结果排序,为模式C(青杨+枸杞)>模式A(川赤芍)>模式D(中国沙棘)>模式B(紫花苜蓿)>模式E(柠条)(223.08、>193.20、>189.87、>155.40、>139.89)。综合考虑生态功能,建议在阴坡推广应用模式C(青杨+枸杞)、阳坡推广应用模式A(川赤芍)。 21在脑山区,林分总蓄水量以模式F(青海云杉)的最大,为331.91mm;土壤总孔隙度、稳渗速率以模式F(青海云杉)的最大,分别为53.62%、6.8mm/min;土壤结构系数以模式H(白桦+青海云杉)的最大,为94.751%;土壤全N、水解N、全K、速效K平均值以模式F(青海云杉)的最高;土壤抗性指数以模式F(青海云杉)的最大,为1.652s/g;群落物种多样性指数以模式H(白桦+青海云杉)的最大,为更多还原

【Abstract】 As a long-term and complex ecological project, the purposes of Converting Cropland to Forest are to rehabilitate vegetation, reduce the losses of soil & water, treat the desertification, improve the deteriorating environment, adjust the structure of rural industry, and to increase the farmers’ income. With the implementation of the project completely, some theories and technology related to the project have been the focus for scientists and decision-makers. However, based on a thorough review on the current studies, we can find that the existing researches mainly concentrate on the specific technology, policies and measures, but few systematical studies on the optimum models of species distribution and the integrated assessment of ecological function.hi consideration of this issue, under the guidance of the basic principles of restoration ecology and the sustainable theory, this dissertation has systematically studied the ecological function of different species arrangement models and selects the optimum ones finally. The study is of significance on offering a theoretical foundation and scientific method for the project implementation in Western China, increasing the ecological benefits, and improving the ecological environment. Meanwhile, it is helpful for the realization of ecological sustainable development of forestry in China both theoretically and practically. The research was carried out in Datong County, Qinghai Province, where is the demonstration site for Converting Cropland to Forest. Based on analyzing industry structure, current land-use status and site classification, five models of Converting Cropland to Forest selected in low mountain and high mountain areas respectively, were investigated in field work and tested accordingly in the laboratory. The relevant analysis, factor analysis and integrated model were adopted to analyze the hydrology effects, soil quality, species diversity and productivity of different models. And the integrated ecological function was also assessed using 18 indices including water-holding capacity of soil, degree of aggregation, organic matter, hydrolytic N, rapidly available P, rapidly available K, species diversity index, and evenness of plant community. The main conclusions are as following:l)In the low-hill area, the total water-holding capacity of model C {Populus cathayana+Lycium barbarum) ranks first in different models of species distribution, up to 329.07mm. Model A (Paeonia veitchii) is better than others on the total pore space ,the final infiltration rate and structural coefficient of soil, which is 56.78%,4.8mm/min,97.61 % respectively. Model C {Populus cathayana+Lycium barbarum), having the highest average content of total N, hydrolytic N, rapidly available P, rapidly available K and organic matte , is obviously prominent in soil nutrient. As for the soil anti-scourability, model D {Hippophae rhamnoides ssp.sinensis), up to 1.136s/g, is ranked first. Model C {Populus cathayana+Lycium barbarum) has the highest biodiversity index (5.3091); model D {Hippophae rhamnoides) has the highest productivity in five models, reaching to 9.36t/(hm2.a).The results of the integrated assessment of the ecological function in low mountain area show that model C {Populus cathayana+Lycium barbarum)>mode\ A {Paeonia veitchii) >model D {Hippophae rhamnoides) > model B {Medicago etiva) > model E {Caragana korshinskii). The indexes of synthetic appraisal are 223.08, 193.20, 189.87, 155.40, and 139.89 respectively.2)In the remote-hill area, the total water-holding capacity of model F{Picea crassifolia) ranks first in different models, up to 331.91mm; Model F{Picea crassifolia) is better than others on the total pore space ,the final infiltration rate of soil, which is 53.62% and 6.8mm/min respectively. Model H {Betula latyphylla+Picea crassifolia) occupies the first place in soil structural coefficient, up to 94.751%. As to the average content of total N, hydrolytic N, total K, rapidly available K and rapidly available K, model F ranks first. The soil anti-scourability of model Y{Picea c更多还原