黄土丘陵区退耕还林后不同林地土壤孔隙与贮水特性

Characteristics of Soil Water-holding and Soil Porosity Under Different Tree Species After Conversion of Cropland to Forest in the Loss Hilly Region

为探索退耕还林工程中树种配置措施对林地土壤水文性质的影响,在黄土丘陵区采用环刀法测定了退耕还林后10年生刺槐、侧柏、油松林分的土壤孔隙度和贮水能力。(1)各种林分都具有明显改善土壤贮水性能的作用,表现为降低土壤容重,增加土壤孔隙度及贮水量;改善程度以刺槐林分为最大,油松林分次之,侧柏林分较小。(2)各种林分对土壤(非毛管孔隙度)滞留贮水量的提高程度均大于对(毛管孔隙度)吸持贮水量的提高程度。(3)林地土壤贮水性能的垂直空间变异性较明显,随着土层深度的增加,土壤容重增加而土壤孔隙度和贮水量减小。

In order to explore the effects of species configuration measures on the nature of soil hydrology in the project of conversion of cropland to forest land, soil porosity and the capacity of water-holding for 10-year-old Robinia pseudoacacia , P lat ycladus orientalis , and P inus tabulae f ormis are determined using forest ring in the loss hilly region. Results show that （1） a variety of stands have significantly improved the capacityof water-holding, i. e. , the performance to reduce soil bulk density and increase soil porosity and soil water-holding. The greatest improvement is by Robinia pseudoacacia, the second is by Pinus tabulaeformis stand, and the third is by Platycladus orientalis. （2） Increase in the amount of residual water of soil（non- capillary porosity） by various stands is greater than the degree of（capillary porosity） water retention. （3） The vertical spatial variability of forest soil is obvious. With the increase in soil depth, soil bulk density is increased, but soil porosity and water storage are reduced.