林木根系对土壤性质的影响研究

发布时间：2018-05-20 23:21

本文选题：根系分布 + 土壤抗剪性能　；参考：《北京林业大学》2015年硕士论文

【摘要】：本研究通过样地挖掘调查和室内实验测定分析相结合的方法,研究了北京鹫峰国家森林公园油松和栓皮栎林地中不同深度土层的根系含量分布与各层土壤力学、物理、化学性质的关系和变化规律。确定了林木根系的固土作用以及植被根系对土壤理化性质的改良作用,综合以上调查分析结果,得出如下研究结论。(1)油松和栓皮栎的各径级根系生物量整体趋势为逐层减小,且各径级根系在表层0～30 cm的生物量明显高于下层土壤；两种植被类型中直径大于5 mm的粗根系在大部分土层中均占主导地位；两种植被类型根系的0～2 mm径级根系在各层土壤中均有分布,且各层生物量与土层深度呈指数函数关系；两种植被类型的各层根系总生物量也与土层深度呈指数函数关系。(2)素土的黏聚力随土层的加深而增大,而加入了根系的土体的内黏聚力却因为根系生物量的逐层减小而随深度增大而逐渐减小,与素土的情况完全相反；土壤黏聚力与土体中含根量以及土层深度都存在线性正相关关系；素土与根-土复合体的土壤内摩擦角随土层的加深变化不大,且没有明显变化规律。随着土层的加深以及根系生物量的逐层减小,不同含根量系列中土壤黏聚力也都呈现出逐层减小的趋势；而深层土壤中由于根系含量较上层土层少,因此土壤黏聚力也比上层土壤小,但在所添加根系的生物量相差不大时,用深层土壤所塑造的根土复合体较浅层的内黏聚力更大；土壤黏聚力与土体中含根量存在线性正相关关系,但不同含根量系列的土壤内摩擦角的变化不大,且没有明显变化规律。(3)样地中土壤的含水率与油松各土层2-5 mm径级根系生物量和栓皮栎各土层根系总生物量的相关性最显著；根系所产生的有机物能有效降低土壤容重,因而土壤容重随着土层中根系生物量的减少而降低；土壤非毛管孔隙度、毛管孔隙度和总孔隙度都随着根系生物量的减小而减小的,这是由于根系的机械穿插所导致的；根系对土壤粒径组成的影响则主要是增加了土壤中0.02 mm粒径的小颗粒物含量。(4)油松和栓皮栎根系对林地土壤中各层间的化学养分含量有累积作用,土壤有机质、全氮、速效氮、全钾、速效钾等养分含量随土层的加深而降低；表层0-10 cm土壤氮素与钾素含量都显著高于下层土壤；而深层土壤中有机质、全氮、速效氮、全钾、速效钾等养分含量的变化较小,且各层之间的差别并不明显。随土层的加深,各土层之间全磷与速效磷含量差异较小,油松和栓皮栎林地全磷与速效磷含量变化规律不明显。(5)根系对土壤性质的影响主要来自于三方面：根系本身的机械物理作用对土壤性质产生的影响；根系所产生的有机物对土壤性质的影响；根系影响区所聚集的土壤生物的活动对土壤的影响。
[Abstract]:In this study, the distribution of root content in different depth soil layers and soil mechanics and physics in different layers of forest land in Jiufeng National Forest Park of Beijing were studied by means of sample excavation and laboratory experiment. The relationship and variation of chemical properties. The effects of soil consolidation of forest roots and the improvement of soil physical and chemical properties by vegetation roots were determined. The results of the above investigation and analysis showed that the overall trend of root biomass of Pinus tabulaeformis and Quercus variabilis decreased layer by layer, and the results showed that the total root biomass of Pinus tabulaeformis and Quercus variabilis decreased gradually. The biomass of 0 ~ 30 cm root system in the surface layer was significantly higher than that in the lower soil layer, and the coarse root system with diameter of more than 5 mm was dominant in most soil layers of the two vegetation types. The 0 ~ 2 mm diameter roots of two vegetation types were distributed in each layer of soil, and the biomass of each layer was exponentially related to the depth of soil layer. The total root biomass of each layer of the two vegetation types is exponential function relation to the depth of soil layer.) the cohesion of the soil increases with the deepening of the soil layer, and the relationship between the total root biomass of the two vegetation types and the depth of the soil layer is also exponential. However, the cohesion of soil with root system decreased gradually with the increase of root biomass, which was completely opposite to that of plain soil. There was a linear positive correlation between soil cohesion and soil root content and soil depth, and the angle of soil friction between pristine soil and root-soil complex changed little with the deepening of soil layer, and there was no obvious change rule. With the deepening of soil layer and the decrease of root biomass, the cohesive force of soil in different root content series also showed a decreasing trend, but the root content in deep soil was less than that in upper layer. Therefore, the cohesion of the soil is smaller than that of the upper soil, but when the biomass of the added roots is not different, the root soil complex created by the deep soil is more cohesive than that of the shallow layer. There was a linear positive correlation between soil cohesion and soil root content, but there was little change in soil friction angle among different root series. The correlation between soil moisture content and root biomass of 2-5 mm diameter and total root biomass of Quercus variabilis was the most significant, and organic matter produced by roots could effectively reduce the bulk density of soil. Therefore, the bulk density of soil decreases with the decrease of root biomass, and the soil non-capillary porosity, capillary porosity and total porosity decrease with the decrease of root biomass, which is caused by the mechanical insertion of root system. The effect of root system on soil particle size composition was mainly caused by the accumulation of soil organic matter, total nitrogen, available nitrogen, soil organic matter, total nitrogen, and available nitrogen by the root system of Pinus tabulaeformis and Quercus variabilis. The contents of total potassium, available potassium and other nutrients decreased with the deepening of the soil layer, the contents of nitrogen and potassium in the surface 0-10 cm soil were significantly higher than those in the lower soil, while the organic matter, total nitrogen, available nitrogen, total potassium in the deep soil were significantly higher than those in the lower soil. The change of available potassium and other nutrient content is small, and the difference between layers is not obvious. With the deepening of soil layer, there was little difference between total phosphorus and available phosphorus in each soil layer. The change of total phosphorus and available phosphorus content in Pinus tabulaeformis and Quercus variabilis forest is not obvious. 5) the effects of root system on soil properties are mainly from three aspects: the effect of mechanical and physical action of roots on soil properties; The effects of organic matter produced by roots on soil properties and the activities of soil organisms gathered in the affected areas of roots on soil.
【学位授予单位】：北京林业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S714

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