鄂尔多斯不同地形下土壤养分的空间变异

通过野外调查采样与室内土壤理化分析相结合,对鄂尔多斯荒漠区不同地貌类型下的土壤养分分布特征进行了初步分析,研究表明:鄂尔多斯沙地土壤养分含量普遍较低,两断面表层有效钾的均值在６４．７３－７０．９５ｍｇ/ｋｇ之间,有机质含量在０．４９３%－０．５０８%之间,ｐＨ值在８．０左右。在地形部位较高的硬梁、丘顶处土壤养分含量最低,软梁次之,而在地势较低的滩地、丘间地土壤养分含量较高。硬梁、软梁、滩地表层土壤有机质和有效钾含量分别为０．１８%、０,５０%、１．１６%和 ３５．２９ｍｇ/ｋｇ、６０、６７ｍｇ/ｋｇ、９８．３２ ｍｇ/ｋｇ,丘顶、丘间、农田表层土壤有机质和有效钾的含量分别为０．０９%、１．０９%、０．８４%和２３．９１ ｍｇ/ｋｇ、６０．３４ｍｇ/ｋｇ、７７．４２ ｍｇ/ｋｇ。在多数土壤剖面上,土壤养分从上到下递减。通过对两地形断面上土壤有机质和有效钾的一维半方差函数均表现出明显的空间结构性,并且各种养分的独立较大,在艾碱壕断面上土壤有效钾和有机质的独立间距为７０．８９ｍ和６９．１５ｍ,在深海沟断面上土壤有效钾和有机质的独立间距为１２．４８ｍ和３５．９８ ｍ,说明在调查区域内土壤养分存在一定的相关关系。

Spatial variability of soil nutrients with different landforms on Erdos Plateau

The result of desertification is not only the degradation of the landscape, but also the declination of the soil fertility. On the Erdos Plateau, the most restrictive factors to the land productivity are soil nutrients and water content. By field investigation and indoor analysis, we studied the characters of the soil nutrients under different landforms on the Erdos Plateau. The content of soil nutrients is very low, but increases from the top to the bottom of hill which is one landform section selected, and so do it on the other landform section selected from the top of the sand-drift to the low-lying field. On the tow landform section, the soil available K of the top layer is between 64.73 ~ 70.95 mg/kg, the organic matter is 0.493 ~ 0.508%, pH is near 8.0. The single dimension semivaiance functions of available K and organic matter have clear spatial structures, and big effective ranges. On the hill section, the effective ranges of available K and organic matter in the top soil are 70.89m and 69.15m; but on the sand-drift section , they are 12.48m and 35.98m. This reveals that the distribution of soil nutrients on different profiles is variable along the section.