新生水土流失对汶川震区土壤水分入渗的影响

摘要

[目的]研究新生水土流失对汶川震区土壤水分入渗的影响.[方法]采用环刀法,分层次取样,研究草坡河小流域4种震后不同恢复类型样地的新生水土流失对土壤入渗的影响.[结果]在新生水土流失的作用下,地表裸露样地、自然恢复样地和人工种植样地的土壤容重、土壤孔隙和持水能力较对照样地(完全未遭地震破坏)差.土壤初渗率、稳渗率、平均入渗速率和75 min渗透总量在4种处理样地均表现为对照样地＞人工种植样地＞自然恢复样地＞地表裸露样地.土壤入渗性能与非毛管孔隙度、总孔隙度呈极显著或显著正相关,与土壤容重极显著或显著负相关,与毛管孔隙度的关系不显著.运用综合判断值(F)评价震后不同恢复类型样地的土壤入渗性能优劣,表现为对照样地(1.2569)＞人工种植样地(-0.2252)＞自然恢复样地(-0.4578)＞地表裸露样地(-0.5738);回归分析表明:通用经验模型和Horton模型的拟合效果较好,比较适合于地震区域土壤入渗特征的模型,Kostiakov模型次之,Philip模型最差.[结论]新生水土流失对土壤水分入渗存在影响,汶川震区对照样地的土壤容重1 g·cm-3左右,土壤总孔隙度50%左右,非毛管孔隙度20%-40%,土壤入渗性能最好.通过自然恢复和人工种植植被等措施可以调控土壤容重和土壤孔隙状况,增强土壤的持水能力,提高土壤水分入渗性能,从而有效地减少地表径流和防止水土流失.%[Objective] This paper discussed the influence on soil infiltration caused by soil and water loss in wenchuan earthquake area. [Method] On the basis of cutting ring method and stratified sampling, we studied the soil infiltration influenced by soil and water loss under four different kinds of sampling plots in caopo river watershed after earthquake. [Result] Under the impact of soil and water loss, soil bulk density, soil porosity condition and moisture holding capacity of the soil of bare land, naturally restored land and cultivated-after-earthquake land were poorer than control (the plots where weren't struck by the earthquake). Soil beginning infiltration rate, steady infiltration rate, average infiltration rate and infiltration amount in 75 min presented control > cultivated-after-earthquake land > naturally restored land > bare land. Pearson correlation analysis result showed that soil permeability showed a highly significant (P cultivated-after-earthquake (-0.2252) > naturally restored land (-0.4578) > bare land(-0.5738). Regression analysis of model simulation indicated that general empirical model and Horton model were the optimal to describe the soil infiltration while Kostiakov model less, Philip model the least.[Conclusion]Soil and water loss influenced soil water infiltration, soil water infiltration capacity of control was the best on Wenchuan earthquake zone while soil bulk density was about 1 gem'3, soil total porosity about 50% , non-capillary porosity 20%-40%. Restoring naturally and planting vegetation which resulted in decrease in soil bulk density, increase in soil total porosity and non-capillary porosity, strengthening of the water holding capacity and improvement of the permeability can reduce the surface runoff and prevent water and soil loss effectively.