宁夏河套灌区典型区域土壤盐碱化空间变异特征

Spatial Variability of Soil Salinization in a Typical Irrigation District of the Hetao Plain in Ningxia

运用经典统计学和地统计学相结合的方法,以宁夏河套灌区盐碱化最严重的区域作为研究区,研究其土壤盐分含量和pH值的空间变异特征。结果表明:土壤全盐含量在表层为强变异性,在其他层次为中等变异性;pH值为弱变异性,其空间变异格局主要由结构性因素引起。土壤全盐含量和pH值均呈现出西北地势低洼地区高于其他地区的空间分布格局,平行于和垂直于贺兰山和黄河走向的方向上土壤全盐含量变异程度较小,而在以沙湖为中心的对角线方向上土壤全盐含量变异程度较大。研究区土壤盐分剖面类型以表聚型为主,底聚型和平均型盐分剖面主要分布于平行于贺兰山和黄河方向偏东的带状区域内和垂直于该方向偏南的带状区域内。

Soil in the irrigation area of Ningxia Hetao was salinized most severely.The distribution characteristics of soil salinity and pH were analyzed in this area by using the classical statistics and geo-statistical methods or GIS techniques.The results showed that the degree of variation for the total salt content was strong at the topsoil,while moderate at the deeper layers.In addition,the soil pH showed a weak variation.The spatial variability pattern was mainly caused by structural factors.The total soil salt content and pH value were higher in the low-lying area of the northwestern Ningxia than in the other areas.The smaller variation in total salt content was found in the areas parallel to and perpendicular to the Helan Mountain and the Yellow River,while the larger variation of soil total salt content was found in the diagonals area at the center of Shahu.The soil salt was mainly concentrated at the topsoil.And the soil salt was accumulated at the subsoil or was even at the whole soil profile in the east strip-shaped region parallel to the Helan Mountain and the Yellow River and perpendicular to the south strip-shaped region.