【作者】 储小院；

【导师】 王玉杰；

【作者基本信息】 北京林业大学 ， 山地灾害防治工程， 2010， 博士

【摘要】 该论文结合国家自然科学基金“基于分形理论的三峡库区林地土壤结构特征与土壤侵蚀关系研究”,进行了重庆缙云山林地土壤侵蚀物理力学机制的研究,以期为三峡库区土壤侵蚀研究及三峡库区的植被建设和生态环境可持续发展提供科学依据。该研究以缙云山典型林分—针阔混交林、常绿阔叶林、竹林、灌木林和农地(对照)作为研究对象,首次采用分形理论综合定量地研究了缙云山林地土壤结构特征,结果为：林地土壤颗粒表面分维(Dj)为混交林最优(2.936),竹林最差(2.908)；微团粒分维(Dw)为灌木林最优(2.582),农地最差(2.718)；团粒分维(Dt)为混交林最优(2.706),农地最差(2.762)；孔隙分维(Dk)为灌木林最优(2.773),竹林最差(2.466)。运用非线性预测法得出林地土壤组成、理化性质指标与土壤结构分维存在非线性关系：γ=αDjβ1Dwβ2Dtβ3Dkβ4,颗粒表面分维的影响要大于微团粒分维和孔隙组分维,但小于团粒分维。采用统计分析、典型相关分析、灰色关联度、逐步回归、主因子分析、模糊聚类等方法,对林地土壤侵蚀物理力学机制和影响因素进行了研究,结果为：典型林地渗透性为灌木林最强,农地最差,初渗率主要受表层土壤颗粒表面分维和团粒分维影响,与其呈负相关,其次是表层土壤微团粒分维和孔隙分维,稳渗率受团粒分维、颗粒表面分维影响作用大于孔隙分维,微团粒分维影响最小,与孔隙分维呈正相关,与其它三者呈负相关。土壤水分入渗过程中,入渗率主要受孔径>1.5mm的孔隙影响,其次是孔径为0.4～0.9mm的孔隙,以及<0.4mm的孔隙。典型林地抗分散性为灌木林地最强(抗蚀指数78.4%),农地最差(抗蚀指数42%)；抗蚀指数随时间的动态变化模型为：S=at2+bt+c；灌木林土壤抗蚀性最强,竹林最差,土壤抗蚀性评价最佳指标为团粒结构破坏率。典型林地土壤抗剪强度为针阔混交林>常绿阔叶林>灌木林>竹林>农地,其主要决定于微团粒分维,其次主要受土壤容重、干密度、粘聚力和硬度的综合影响。典型林地土壤抗冲指数随时间变化特征为幂函数关系K=at-b；土壤抗冲指数与坡度的关系为：K=0.0755e0.0755x,农地土壤抗冲性受坡度影响最为强烈,竹林最小；针阔混交林土壤抗冲性最强,农地土壤抗冲性最弱；土壤抗冲能力主要受孔隙分维、团粒分维、大孔隙平均半径和稳渗率四个指标影响,其次为大孔隙断面积比、结构颗粒指数和有机质。典型林地土壤侵蚀临界切应力为针阔混交林最大(1.257N／m2),农地最小(0.824 N／m2),临界切应力主要决定于土壤的抗剪强度,是反映土壤侵蚀能力的一个重要指标。从土壤渗透性、抗分散性、抗剪性与抗冲性四个方面筛选抗侵蚀性指标,采用层次分析法(AHP)、综合评分法对典型林地土壤抗侵蚀性能评价结果为：灌木林(1.260)>针阔混交林(1.169)>常绿阔叶林(1.106)>竹林(1.066)>农地(1.042)。灌木林地土壤抗侵蚀性能最强,农地土壤抗侵蚀性能最差。该论文较为全面和深入地研究了缙云山林地土壤侵蚀物理力学机制,提出了土壤抗侵蚀的土壤因素评价指标体系,并得出了缙云山不同典型林地类型土壤抗侵蚀性能,填补了缙云山林地土壤侵蚀物理力学综合研究与评价的空白。更多还原

【Abstract】 The research on the physical and mechanical mechanism of soil erosion of forest in Jinyun Mountain of Chongqing City was conducted, which are associated with the National Natural Science Fund project "The Relationship Research between Soil Structure Characteristics and Soil Erosion of the Three Gorges Reservoir Area Based on Fractal Theory ". The purpose of this paper is to provide scientific evidence for soil erosion research and vegetation construction and sustainable ecological environment development of the Three Gorges reservoir area.Soil structure of four typical forest lands (mixed Pinus massoniana-broadleaf forest, evergreen broad-leaved forest, Phyllostachys pubescens forest and shrub forest) and the agricultural land in Jinyun Mountain, was comprehensively and quantitatively studied by the method of the fractal theory for the first time. The results are as follows:particle size fractal dimension (PSD) of mixed forest land was optimal (2.936), the one of Phyllostachys pubescens forest land was worst (2.908); micro-aggregate size fractal dimension (MASD) optimal for shrub forest land (2.582), the one of agricultural land was worst (2.718); aggregate size fractal dimension (ASD) optimal for mixed forest land (2.706), the one of agricultural land was worst (2.762); pore fractal dimension (PFD) for shrub forest land optimal (2.773), the one of Phyllostachys pubescens forest land was worst (2.466). With the method of nonlinear predictive indicators, the relation between soil properties and soil structure fractal dimension was fitted by the model ofγ=αDjβ1Dwβ2Dtβ3Dkβ4. PSD’s impact on the model was greater than MASD and PFD, but less than ASD.The physical and mechanical mechanism of soil erosion of forest was analysized and evaluated by the methods of statistical analysis, canonical correlation analysis, grey reational analysis, stepwise regression, principal component analysis, fuzzy-clustering analysis and other methods, the results were as follows:Impermeability of shrub forest land was the strongest, while agricultural land was worst. Initial infiltration rate was mainly affected by PSD and ASD, followed by the MASD and PFD. Effect on steady infiltration rate with ASD and PSD was greater than PFD, the least was MASD. Infiltration rate was mainly affected by pore (aperture> 1.5 mm), followed by the pore (aperture was amang 0.4 to 0.9 mm), the least was pore (aperture< 0.4 mm). Anti-dispersion of shrub forest land against was the strongest (78.4%) and agricultural land was the worst (42%). Anti-dispersion dynamic changes with time was fitted by the model of s=at2+bt+c. The best indicator of anti-erodibility evaluation was the disarrangement rate of aggregate. Anti-erodibility of shrub forest land was the strongest and Phyllostachys pubescens forest land was the worst. The order of soil shear strength was mixed forest land> evergreen broadleaf forest> shrub forest> Phyllostachys pubescens forest> agricultural land, which was mainly affected by MASD, followed by bulk density, dry density, cohesion and the hardness. The index of soil anti-scouribility had the great remarkable power function with time and its relation with slope was fitted by the model of K= 0.0755e 0.0755x.Soil anti-scouribility of mixed forest land was the strongest, Phyllostachys pubescens forest land was the weakest, it was mainly affected by PFD, ASD, macropore radius and steady infiltration rate, followed by macropore section area ratio, structure index and organic matter. Critical shear stress of mixed forest land was the largest (1.257 N/m2), agricultural land was the smallest (0.824 N/m2), the critical shear stress depended mainly on soil shear strength.Impermeability, anti-erodibility, shear strength and anti-scouribility reflect the physical and mechanical mechanisms of soil erosion, soil erosion which are important indicators to evaluate the degree of soil erosion. Then, the method of analytic hierarchy process was applied to evaluate the degree of soil erosion under the typical forest land, the result is as follows:shrub forest (1.260)> mixed forest land (1.169)> evergreen broadleaf forest (1.106)> Phyllostachys pubescens forest land (1.066)> agricultural land (1.042). Therefore, the resistance to soil erosion of shrub forest land is the strongest, and agricultural land was the worst. Forest vegetation can improve soil anti-erosion. The physical and mechanical mechanisms of soil erosion in Jinyun Mountain was studied in-depth, the evaluation index system of soil anti-erosion was proposed, and soil anti-erosion properties of different typical forest lands were obtained. It fills in the blanks of analysis and evaluation of physical and mechanical system of soil anti-erosion in Jinyun Mountain.更多还原