降雨过程中不同密度枯落物对各土层含水率动态影响

陈佩岩; 马岚; 梅雪梅; 张栋; 薛孟君; 孙一惠

doi:10.13332/j.1000-1522.20180078

降雨过程中不同密度枯落物对各土层含水率动态影响

Dynamic influence of different density litter on moisture content in each soil layer during rainfall process

摘要

摘要:
目的以晋西黄土区典型油松林及刺槐林为研究对象, 对其枯落物层和土壤层水文效应进行初步研究，以期为该区建设水源涵养林及水土保持林提供一定的借鉴依据。
方法分别选取对应林分3种密度枯落物后进行野外人工降雨，并对其覆盖下0~20 cm、20~40 cm、40~60 cm、60~80 cm、80~100 cm、100~120 cm 6个土层含水量实时监测。
结果(1) 在同一雨量级别下，当枯落物覆盖密度增加时，其在降雨过程中的截留量以及枯落物最终达到饱和截留量的时间也随之增加；此外，随着降雨试验的进行，截留率随之减小，且其随枯落物的密度增加而升高。(2)降雨过程中，随着枯落物密度的增加，两种林地上层土壤(0~60 cm)的含水率均呈现逐渐减小的趋势；其中0~20 cm土层含水率对降雨的响应最为直接和迅速，而20~40 cm与40~60 cm土层的土壤含水率变化有一定的滞后和延长，较深层(60~120 cm土层)土壤含水率对降雨过程几乎无响应过程。(3)降雨结束后，各深度土层的含水率均表现出随时间的持续缓慢减小；降雨结束24 h内，裸地及各密度枯落物覆盖下的土壤含水量最高均出现在0~20 cm层；当入渗48 h后，裸地土壤含水量最高则出现在20~40 cm土层，但是对于有枯落物覆盖的土壤，0~20 cm土层含水率在降雨结束48 h内始终最高，并且随着密度的增加其随时间延续而减小的幅度越小。
结论截留量、截留率与降雨历时(降雨量)均符合幂函数关系(R²>0.9)；在降雨前后及过程中，不同密度枯落物对其覆盖下的土壤含水率有较大影响；不同深度土层含水率对降雨响应差异显著。

Abstract:
ObjectiveTaking the typical Pinus tabuliformis forest and Robinia pseudoacacia forest in the Loess Plateau of western Shanxi, northern China as the research object, the preliminary study was conducted on the hydrological effects of litter layer and soil layer in order to provide reference for the construction of water conservation forests and soil and water conservation forests in the area.
MethodAfter selecting the forest corresponding to litter of three densities, artificial rainfall was performed. The moisture content of 6 soil layers including 0-20 cm, 20-40 cm, 40-60 cm, 60-80 cm, 80-100 cm, and 100-120 cm was monitored in real time.
Result(1) At the same rainfall level, the interception of litters increased with the increase of density, and the time for the interception to reach saturation was also prolonged; the rate of interception decreased with the increase of rainfall, and increased with litter density. (2) During rainfall process, with the increase of litter density, the water content of the top soil (0-60 cm) of both types of forests gradually decreased. The 0-20 cm soil moisture content response to rainfall was the most direct and rapid, while the change of soil moisture content in 20-40 cm and 40-60 cm soil layers had a certain lag and extension, the soil moisture content in deeper soil layer (60-120 cm) had almost no response to the rainfall process. (3) After rainfall, the moisture content in all depths of the soil layers showed a continuous decrease with time. Within 24 hours after the end of rainfall, the soil moisture content under bare land and all litter with different densities was highest in the 0-20 cm layer. After 48 hours of rainfall, the highest soil moisture in bare soil occurred in 20-40 cm soil layer, however, for soils covered with litter, the moisture content in the 0-20 cm soil layer was always the highest within 48 hours after the end of rainfall, and as the density increased, the magnitude of the decrease over time decreased.
ConclusionThe relation between interception or its rate and duration of rainfall accords with the power function relation(R²>0.9). Before and after rainfall, the litter with different densities has a great influence on soil moisture content. The moisture content in different soil layer shows a significant differences in response to rainfall.

HTML全文

参考文献(27)

施引文献

资源附件(0)