黄土丘陵区植被的土壤水文效应

A study on the effect of soil moisture of different vegetations in Loess Hilly Region

采用定位监测与普查相结合方法,对黄土丘陵区主要降水量级地区不同植被下土壤水分状况进行了系统的总结分析。研究认为:农林草地土壤水分剖面有较大差异,土壤水分由高到低依次为农地、草地、灌木地、乔木。部分地区灌木林土壤水分可能不如乔木林地。在特旱年份,不同植被下的土壤水分严重亏缺,但不同植被利用引起的土壤水分差异变小。森林带土壤水分明显好于过渡带,该带刺槐生长正常;在过渡带,特旱年份油松、刺槐林不能正常生长,且乔、灌、草均引起土壤干层。所以在林草植被建设中需要一些辅助措施来保证土壤水分供应的可持续性。

Based on data collected by system soil moisture survey and random survey in Loess Hilly Region,in this paper,authors had analyzed systemically soil moisture status of different vegetation land in many sits with rainfall ranges from 400~580 mm.The research showed that the soil moisture profile was different.The order was that farm land>pasture land>shrub community land>arboreal forest.Sometimes,the soil moisture of arboreal forest may be higher than that of shrub land because of the lower productivity and plant density of the community.In extreme drought period,soil water extracted,and then decreased to a low degree,therefore gap in the soil moisture of different type vegetations reduced,even vanished.The vegetations exempt crop could bring a dry soil layer in the soil profile.The soil moisture in more rainfall region where acacia could grow normally was better than that of lower rainfall regions where arboreal forests growing were restricted by soil water supply.So some water protection methods need to be put in to practice in order to prompt plantgrowing.