【作者】 赵钦；

【导师】 陈林武； 宫渊波；

【作者基本信息】 四川农业大学 ， 森林培育学， 2009， 硕士

【摘要】 本文以岷江上游理县山地森林-干旱河谷交错带地区退耕还林后的土壤为研究对象,根据海拔高度划分为典型干旱河谷地段、交错带和山地森林段,并分别在每个地段分别选取代表性植被类型,开展植被调查和土壤取样分析,探讨不同植被条件下土壤理化性质在不同环境因子下的变异情况和变化规律,探索山地森林-干旱河谷交错带植被恢复及管理的调节机制,充实交错带生态演化过程理论,为山地森林-干旱河谷交错带植被恢复及复合生态系统管理提供理论依据。研究主要结果如下:①研究区不同植被类型土壤容重在0.96～1.65 g.cm^-3之间,随土层加深而增大;土壤孔隙度是表层优于下层。表层土壤pH值在低海拔荒地与岷江柏林处最高,随着海拔高度的增加而降低。亚表层土壤pH值变化趋势相同,但（10～20cm）高于上层（0～10cm）。土壤机械组成主要以粒级d＜0.25mm和0.25～0.5mm为主,土壤物理性质表层变异大于下层变异,其主要原因应与土壤水分含量变化和人为活动等有关。②研究区粘粒粒级（＜0.002mm）粉粒粒级（0.02-0.002mm）含量普遍较高,同时随海拔梯度增加与植被覆盖的增加其含量呈增加的趋势。细砂粒级（0.25-0.02mm）含量次之,但其含量随海拔梯度增加和植被覆盖的增加而降低。③随着海拔高度增加和植被恢复,土壤全氮、全磷、有效磷、全钾、速效钾及有机质含量之明显增加,表明研究区土壤水分和植被因素是影响土壤养分状况的主要因子。除土壤有机质外,土壤中各养分含量与土壤容重呈显著负相关关系,说明土壤容重越高,土壤越板结,土壤养分含量越低。植被恢复后各季节土壤有机质、全氮、全磷、速效磷、全钾、速效钾含量均增加,各林分土壤养分含量为秋季＞冬季＞春季＞夏季。表明植被恢复能明显的改良土壤,增加土壤养分含量。植被恢复类型上,交错带上缘天然恢复的青冈、桦木次生林养分含量最高,交错带下缘各人工恢复林养分含量次之,干旱河谷段岷江柏林与荒地养分含量最低。④交错带山地森林和人工林所处地段的土壤养分状况优于干旱河谷段,表明该区自然环境条件相对于河谷下部优越,只要进行人工造林并采取封禁措施,减少放牧干扰,植被就能快速恢复。因此,在植被恢复过程中应考虑海拔对土壤养分分布的影响。沿交错带逐步向下恢复森林,使林线下移,最终达到干旱河谷区植被恢复的目的,是干旱河谷区植被恢复的一条行之有效的途径,可在干旱河谷区进行植被恢复时推广。⑤各林分土壤微团聚体分形维数的大小为:次生林＞灌木＞刺槐林＞阔叶混交林＞针阔混交林＞岷江柏＞荒地;2＞荒地1。在垂直方向上,团聚体分形维数PFD是山地次生林＞交错带＞干旱河谷段,可以看出山地森林/干旱河谷交错带植被恢复情况是高海拔优于低海拔,这为干旱河谷区植被恢复从上至下逐渐推进,提高植被恢复成效提供了理论依据。决定分形维数是土壤细颗粒的含量,植被恢复后,淋淀粘化作用加强,且随着大量枯落物的归还及植被对风蚀物和降尘的截获效应,土壤细颗粒物质增加,土壤分形维数升高,土壤肥力与结构变好,说明分形维数可以反映干旱河谷植被恢复的程度。交错带内PFD是灌木＞刺槐林＞阔叶混交林＞针阔混交林,灌木林由于减少了干扰的影响优于其它植被类型,表明在山地森林/干旱河谷交错带植被恢复中,进行封禁管理应是确保植被恢复效果的重要措施之一。更多还原

【Abstract】 In this paper,the returning farmland to forest soil which in mountain forest - the arid valley of ecotone in Li County in the upper Minjiang River was studied. According to altitude,we divide the study area into three parts:typical arid valley area, ecotone area and mountain forest area.In these three parts,we choose representation of vegetation types respectively,and carry out vegetation surveys and soil sampling analysis.Study the soil physical and chemical properties Variability and change under different conditions of vegetation and under different environmental factors.Explore the mountain forest - the arid valley of ecotone vegetation restoration and management of the adjustment mechanism,and enrich Ecotone ecological theory of evolution,and ultimately to provide a theoretical basis in the mountain forest - the arid valley of ecotone vegetation restoration and management of complex ecosystems.The results indicated:①The soil bulk density under different vegetation types is around 0.96-1.65 g/cm~3 in the study area,and with soil depth increased;The soil porosity of surface layer is better than the lower.The PH of surface layer is greater in lower altitude (wasteland and Cupressus chengiana) and with the increase in altitude to reduce.The PH of sub-top soil has the same trend,but the value of its upper(0-10cm) is small than the lower(10-20cm).Due to the change of soil water content,human activities and other reasons,the majority of soil mechanical composition size are d＜0.25mm and 0.25～0.5mm,and variability of soil physical properties,the surface is greater than the lower.②The content of clay size(＜0.002mm) and granule size(0.02-0.002mm) is relatively high,and it increase with the increase in altitude and the increase in vegetation cover.The fine sand content of the second,but it reduces with the increase in altitude and the increase in vegetation cover.As the clay size and granule size can easily form their own micro-aggregates or soil organic matter to form a stable aggregate structure,enhance the corrosion resistance of the soil,this indicate that the increase in altitude soil corrosion resistance gradually enhanced in the study area.③With the increase in altitude and vegetation restoration,the content of soil total nitrogen,total phosphorus,available phosphorus,total potassium,available potassium and organic matter have a marked increase in the study area showed that soil moisture and vegetation are the main factors influencing soil nutrient status.In addition to soil organic matter,the soil nutrient content and the soil bulk density was significantly negatively related to illustrate the higher soil bulk density,soil compaction and Vietnam,the lower the nutrient content of soil.After restoration of vegetation,soil organic matter,total nitrogen,total phosphorus,available phosphorus,total potassium, available potassium increased in four seasons.The soil nutrient content in the stands: autumn＞winter＞spring＞summer.It shows that the restoration of vegetation significantly improved the soil,increase soil nutrient content.For the types of restoration of vegetation,the natural recovery Cyclobalanopsis and birch have the highest nutrient content,which followed by the Plantation,the Cupressus chengiana and wastelanarid in the arid valley of Minjiang River have the lowest nutrient content.④Mountain forest - ecotone area and plantation area where the soil nutrient is superior to the arid valley area shows that the natural conditions of the area is superior to the lower valley,as long as the afforestation,closed forest measure and to reduce the disturbance of grazing,vegetation can be rapid recovery.Therefore,in the process of vegetation restoration,the impact of elevation on the distribution of soil nutrients should be considered.Along ecotone,restoration forest step by step and make the timberline down,and ultimately to achieve the restoration of vegetation in arid valley, is a well-established channel in arid valley vegetation restoration,can be carried out in the arid valley of the promotion of vegetation recovery.⑤The size of soil micro-aggregates of fractal dimension in the stands:secondary forest＞shrub＞Robinia pseudoacacia forest＞mixed forest＞coniferous forest＞Minjiang hodginsii＞wasteland 2＞wasteland 1.In vertical direction,PFD of the aggregate fractal dimension:Mountain secondary forest＞ecotone＞Dry Valley area. That indicate the mountain forest - arid valley ecotone vegetation restoration is high-altitude superior to low-altitude,providing a theoretical basis improve the effectiveness of the restoration of vegetation in arid valley vegetation restoration,of gradually advancing from top to bottom to.Decision is the fractal dimension of the content of fine particles of soil,after vegetation restoration,the leaching of the enhanced role of visco-lake,and with a large number of the return of litter and vegetation on wind erosion and dust of the intercepted material effect on fine particulate matter increased the soil,soil the fractal dimension increased,soil fertility and structural change,and that the fractal dimension can reflect the vegetation in the arid valley of the degree of recovery.PFD of ecotone:shrubs＞Robinia pseudoacacia forest＞mixed forest＞coniferous forest.Due to the impact of a reduction of interference,shrub is superior to the other vegetation types,indicating that in the mountain forest - arid valley of ecotone,closed forest is the one of the important measures in ensuring vegetation recovery.更多还原