河西走廊敦煌绿洲天然胡杨林土壤水分空间变化特征研究

The Spatial Variations of Soil Water Content under the Populus euphratica in Dunhuang Oasis in Hexi Corridor

利用经典统计学与地统计学相结合的方法对甘肃敦煌绿洲天然胡杨林土壤含水量的空间变化规律性进行研究。结果表明:敦煌绿洲天然胡杨林土壤含水量变化趋势总体表现为随深度增加而不断增加的趋势。0-60 cm土壤含水量变化程度较大,再向下各层土壤含水量变化趋于平缓。土壤水分变异系数在不同土壤层有较明显的差异,土层越深,其含水量变化程度越小,这主要与气候、土壤质地及树龄等因素有关。采用GIS的反距离加权(Inverse Dis-tance Weighted)插值法分析表明,研究区土壤含水量存在明显的空间差异和较强的相似性。即各层均表现为自西向东逐渐增加的空间格局,这与西临库姆塔格沙漠和罗布泊东靠绿洲的地貌格局相一致。

The spatial variability of soil water content is remarkable.Here we used traditional statistics and semivariance analysis of geostatistics to study the spatial variability of the soil water content under the natural populus euphratica forests in the west lake nature reserve of Dunhuang oasis.The results showed that there are about 15-20 cm dry sand layers in most parts of land.That makes the surface soil water content at the lowest level,between 0.8%～4.49%.The soil water content is raised from upper to lower,but not very obvious at different layers.The soil water content changed sharply in 0-60 cm and changed moderately in 60-120 cm.The variation efficient of the soil water content is obviously different in different soil and becomes smaller with the depth increasing.The change is mainly relative to climate,soil texture and tree-age and so on.Using the GIS（Inverse Distance Weighted,IDW） interpolation method analysis,the soil water content of study area exist obvious space differences and strong comparability.Each layer is gradually increased spatial pattern from west to east.It was consisted with the topographical features of the west of the Kumtag desert and the Lop Nor region and the east of Dunhuang oasis.