科尔沁沙地人工植被对土壤水分异质性的影响

选择植被状况基本相同而坡位不同的样地 ,坡向和坡度基本相同而植被类型不同的沙丘背风坡 (东南坡 )样线及沙丘上部样地 ,在生长期调查其土壤水分状况 ,探讨植被类型、坡位对沙地土壤水分状况及水分格局的影响。结果表明 :沙丘背风坡 (东南坡 )人工植被土壤水分状况按差巴嘎蒿、杨树、樟子松的次序依次变差。以 0 5m为间隔取样分析表明沿沙丘下部到沙丘上部土壤水分状况有下降趋势。在水平格局上 ,樟子松林地土壤水分状况在0～ 8m ,杨树林地在 0～ 4m ,流动沙地在 0～ 9m的尺度上近似同质 ,随着空间距离的增加 ,异质性加强 ;差巴嘎蒿土壤水分状况在 0～ 4m的范围内异质性较高 ,4m以上近似同质。在垂直格局上 ,流沙在 0～ 60cm ,樟子松在 0～ 80cm ,差巴嘎蒿在 0～ 1 2 0cm的尺度上异质性很强 ,大于该尺度近似同质 ,而杨树林地在 0～ 30 0cm的范围内均有较强的异质性。无论水平格局或垂直格局 ,人工植被的建立增强了沙地土壤水分的异质性

IMPACT OF PLANTATION ON SPATIAL HETEROGENEITY OF SOIL MOISTURE IN HORQIN SANDY LAND

Eight plots with ?Artemisia halodendron, Populus? and ?Pinus? plantations and shifting sandy land both four at leeward with similar slope and exposure and four on top of dune respectively, and three plots with similar ?Hedysarum fruticosum var. ligosum? plantation at bottom, middle and top of sand dunes were chosen to monitor soil moisture to determine impacts of the plantation on both soil moisture regime and soil moisture spatial heterogeneity by using fractal dimension and semivariograms in Horqin Sandy Land. The results show that: (1) the soil moisture regime of the plots worsens in the order of ?Artemisia halodendron, Populus? and ?Pinus? plantation; (2) the soil moisture is significantly dependent on its position at the sand dunes; (3) horizontally, the soil moistures for ?Populus, Pinus? plantations and shifting sand land plots exhibits homogeneity within the scale of 4m, 8m and 9m, respectively. However, that for ?Artemisia halodendron? plantation plot show high heterogeneity within the scale of 4m, and homogeneity at the scale of 4m above. Vertically, the soil moisture for ?Artemisia halodendron, Pinus? plantation and shifting sand land plot exhibits heterogeneity within the depth of 120cm, 80cm, 60cm, respectively, and homogeneity in the depth lower. However, ?Populus? plantation plot shows great heterogeneity within the depth of 300cm. In a word, heterogeneity of soil moisture for plantation plots is higher than that for shifting sandy land plots both on horizontal and vertical scales.