基于植物水文属性的水土保持机理研究

The hydrological attributes of plant plays an important role in hydrological function of ecosystem, but most of the studies on the hydorlogical processes of plant community showed that vegetation parameters mainly affected the hydrological function of ecosystem at the stand level.However,it was not enough for clarifying the relation between plant hydrological attributes and the mechanism of soil and water conservation.Some studies showed that plant morphology changed ecological processes and then affected the hydrological function of ecosystem, so on basis of plant morphology and hydrological processes experiment, the study on the relationship between plant hydrological attributes and ecosystem function are important for understanding the mechanism of the ecosystem services of hydrological function. However, the study about the above these is less. In the previous works,we found that canopy interception and runoff related with the ecological factors of speices richness and composition of community, yet the study on plant hydrological attributes is necessory for analyzing the mechanism of soil and water conservation of communty. On basies of above discussing, four tpyes of vegetation are investigated, plant morphological characteristics are measured, and these hydorlogical processes including plant interceptionsoil, infiltration, and hill-slope water erosion are experimented. By analyzing these experimental date, we will assess the hydrological attributes of plant. Moreover, the hydrological attributes, hill-slope water erosion and community structure are correlatively analyzed to clarify the relationship between plant morphological characteristics and hydrological function. These works of this project can explain the mechanism of soil and water conservation of community at three level of morphology-plant attributes-ecological process.

植物水文属性在系统的水文功能中起重要作用，然而之前在立地水平上对水文过程研究发现植被参数是影响系统水文功能的关键因子，但不能阐明植物水文属性与水土保持机理的关系。研究表明植物形态特征改变生态过程，进而影响生态系统水文功能，因此从植物形态特征入手，结合水文过程，研究植物水文属性有助于揭示生态系统水文功能服务机制。然而目前却未见到这方面的研究。在我们前期工作中发现植物群落林冠截留、地表径流过程与物种丰富度、物种组成等参数相关，还需对植物水文属性进行研究，才能深度探究水土保持机理。基于此，本项目以滇中地区具有代表性的四种植物群落为研究对象，测定植物形态特征，结合植物对降雨截留的水文实验，土壤入渗及坡面产流试验，评价植物水文属性；对植物水文属性、坡面产流过程和群落数量特征进行相关分析，揭示植物形态特征-水文功能的关系，在个体形态-水文属性-生态过程三个研究层次上阐明水土保持机理。

植物群落结构与生态系统功能表现为协同增强的效应，开展植物群落结构及生态过程关系的研究已成为重要科学问题。本研究以滇中地区荒坡灌草丛、云南松林、桉树林、针阔混交林、次生常绿阔叶林五种植物群落为研究对象，进行植被调查、植物形态特征与水文属性、各个界面的水文过程进行研究。. 植物群落聚类分析结果表明：荒坡灌草丛、云南松林、针阔混交林及次生常绿阔叶林依次为地带性植被—半湿润常绿阔叶林恢复演替过程中的不同阶段，物种组成、丰富度、多样性指数、逐渐向地带性植被半湿润常绿阔叶林发展；桉树林人工林物种组成单一，结构简单。. 常绿阔叶树种的吸附水量（率）高于落叶阔叶树种。结合植物叶形特征及其吸水性能，评价植物水文属性，发现滇中植物物种分成三个吸水功能群；植物群落林冠截留是次生常绿阔叶林林冠截留量最高，其次针阔混交林>云南松林>桉树林，林冠截留模型为对数模型 。地表径流量为桉树林>云南松林>荒坡灌草丛>针阔混交林>次生常绿阔叶林。群落垂直结构分层、多样性指数、物种组成、盖度等群落结构参数显著影响林冠截留及地表径流量。枯落物层蓄水量也表现为物种组成单一的植物群落其枯落物层枝叶组成单一致使涵养水源的能力不及物种组成丰富的植物群落。. 群落的土壤剖面水分含量因群落结构的差异导致30cm土壤层水分含量的变异系数最大。土壤入渗过程符合Horton入渗模型。饱和导水率的大小顺序为：次生常绿阔叶林>针阔混交林和荒坡灌草丛>云南松林>桉树林；到达稳渗率的时间为云南松林和桉树林高于其它植物群落。随群落结构复杂程度的升高，土壤容重下降，总孔隙度及有机质含量递增；土壤入渗与土壤容重成负相关关系，与总孔隙度及有机质含量成正相关关系。.应用异速增长模型估算生物量并测定各优势物种各器官的营养元素含量，发现优势物种氮、磷、钾营养元素贮存总量表现为：桉树林>云南松林>针阔混交林>次生常绿阔叶林>荒坡灌草丛，生物量中营养元素的高贮存量不利于土壤肥力的改善。