黄土丘陵沟壑区深层土壤水分空间变异及其影响因子

Spatial Variation of Deep Soil Water in the Loess Hilly and Gully Regions and Its Influencing Factors

以甘肃省定西市龙滩流域为例,对比分析了不同坡位、坡度和坡向典型植被(柠条林地、油松林地、侧柏林地、苜蓿草地、荒草地和农地)0～8 m深度土壤水分的空间变异状况。结果表明,不同植被和地形条件下,深层土壤水分的剖面分布特征均表现为随土层深度增加而增加。地形是浅层土壤水分空间变异的重要影响因子,而植被生长状况是深层土壤水分空间变异的决定因素,植被生长越好则深层土壤含水量越低。坡度对深层土壤水分有显著影响,缓坡地土壤含水量显著高于陡坡地。水土保持工程和耕作管理措施能有效提高深层土壤含水量,可作为提高土壤储水的有效途径。

Spatial variation of soil water content in soil profiles 0-8 m deep as affected by landform and vegetation was studied in the Longtan catchment of Dingxi in Gansu Province.Results show that topographic factors,such as position,inclination and exposure of a slope have significant influences on content of shallow soil water.However,spatial variation of deep soil water is more affected by growth conditions of the vegetation thereupon.The vegetations different in growth condition differ in consumption of soil water,thus the better the vegetation grows,the lower the content of deep soil water is.Slope gradient has significant influences on both shallow and deep soil waters.Soil water content is obviously higher in gentle slopes than in steep slopes in the entire 0-8 m soil profile.Management measures such as soil and water conservation and tillage activities can effectively enhance infiltration of rain water,thus increasing soil water storage in deep soil layers,and therefore be extrapolated as effective approaches to improvement of soil water regime in this region.