【摘要】 植物的蒸腾作用会改变土的基质吸力,进而影响土的力学性质。文章选用三种不同蒸腾速率的鸭脚木、绿萝和常青藤,利用主动加热光纤法(AHFO)对植物根系周围土的含水率进行了分布式测试,研究了植物蒸腾过程中的水力作用,评价了常用的描述植物与土的水力交互作用的蒸腾分割模型。试验结果表明:植物对土中含水率的影响可用蒸腾分割模型进行有效描述,含水率变化受植物叶面积、根系密度、土层深度和蒸腾时间的影响;绿萝与鸭脚木叶面积指数和根系密度相近,二者引起根部周围土中的含水率变化值相近,为0.075 m3/m3,常青藤的叶面积指数和根系密度远远大于绿萝与鸭脚木。因此,常青藤引起的根部周围土中的含水率变化值远大于其他两种植物,为0.125 m3/m3;植物对土中水分运移的影响主要在土的表层10～15 cm深度范围内,深部位置的水分场几乎不受植物的影响;湿润后,植物对土中含水率的影响以干燥初期最为显著,主要由植物的被动吸水作用引起。更多还原

【Abstract】 The transpiration of plants will change the matric suction of soil and affect the mechanical properties of soil.In this paper,three kinds of plants are chosen with different transpiration rate:ivy tree bark,scindapsus aureus and Ivy League,active heating fiber optic(hereinafter referred to as AHFO),and are adopted to test on the moisture content of soils distributed around the plant roots.This paper also examines the hydraulic effect in the process of transpiration and evaluates the transpiration segmentation model which is commonly used to describe hydraulic interaction between plants and soil.The experimental results show that(1) the influence of plants on soil moisture content can effectively be described by the transpiration segmentation model,and the change in water content is affected by the plant leaf area,root density,soil depth and transpiration time.(2) The leaf area index and root density of ivy tree bark and scindapsus aureus are similar,and the change value of water content in soil around the root is similar(0.075 m3/m3).The leaf area index and root density of Ivy League are much higher than those of ivy tree bark an scindapsus aureus.Therefore,the change value(0.125 m3/m3) of moisture content in the soil around the root caused by IvyLeague is much higher than the other two plants.(3) In this experiment,the depth influenced by plants on the water transport in soil ranges mainly from 10 to 15 cm,and the water field at depth is almost not affected by plants.(4) After wetting,the influence of plants on soil moisture content is most obvious at the early stage of drying,which is mainly caused by the passive water absorption of plants.更多还原