Effects of Different Vegetation Types on Soil Moisture in Deep Loess Soil Profiles
不同植被类型对厚层黄土剖面水分含量的影响

This study was to examine the effects of main vegetation types on soil moisture and its interannual variations.Soil moisture in 0-10m deep profiles of six vegetation types,i.e.,crop,grass,planted shrub of caragana,planted forests of arborvitae,pine and the mixture of pine and arborvitae were measured in 2001,2005 and 2006.Soil moisture in about 0-3m of cropland and about 0-2m of other vegetation types varied interannually dependent on annual precipitation,but was rather stable interannually below this depth under all six vegetation types.In 0-2m,soil moisture of cropland was significantly greater than those of all other vegetation types,but there were no significant differences among other vegetation types.In 2-10m,there was no significant moisture difference between crop and grass,but the soil moisture of both was significantly higher than planted brush and forests.The planted caragana brush and forests had depleted soil moisture below 2m to or near wilting point,and there were no significant soil moisture differences among different forest types.