银川平原土壤盐分及盐渍土的空间分布格局

系统认识和掌握盐渍土的空间分布特征，是治理改良盐渍土的基础。在总面积约6 184.9 km2的银川平原引黄灌区布设101个采样点，分层（0～180 cm）测定了土壤全盐量，应用地统计学方法结合GIS技术对其空间分布特征进行了研究。结果表明，银川平原各层土壤盐分的分布类型均比较复杂，呈高度的偏态分布。土壤盐分的变异属于中等变异强度。0～120 cm土层盐分的空间相关距离一般在20～28 km；而深层（＞120 cm）土壤的空间相关距离较大，约34 km。银川平原表层土壤属于非盐化土、轻度、中度、重度盐渍土和盐土的土地面积分别为0、1 508.8、3 614.9、982.6和78.6 km2，总体属于中度和轻度盐化土类型，且呈现一定的盐分表聚趋势。重度盐渍土和盐土主要分布在银北的石嘴山市、平罗县、惠农县一带和银南的部分地区。总体来说，银川平原的土壤盐渍化现象依然严重，应加强研究与治理改良。

Spatial distribution pattern of soil salinity and saline soil in Yinchuan plain of China

Understanding the characteristics of spatial distribution of saline soil is important in establishing strategies for soil salinity management. One hundred and one soil samples were collected from 0 to 180 cm in irrigation areas in Yinchuan Plain with an area of 6184.9 km2 and soil salinity for each sample was measured. The geostatistical method and GIS technique were used to analyze the data. The results showed that spatial distribution of salinity in each layer of soil presented highly skew distribution. The coefficient of variation for soil salinity belonged to medium degree of variability. Soil salinity in surface layer (0-120 cm) was spatially correlated at a distance between 20 and 28 km, while the spatial correlated distance for subsoil (120-180 cm) was larger (about 34 km). The areas of non-salinity, light salinity, medium salinity, heavy salinity and saline levels were 0, 1 508.8, 3 614.9, 982.6 and 78.6 km2, respectively. The soil salt concentrations of surface soil in Yinchuan plain were mostly classified at medium and light salinity levels, and presented a trend of soil salt accumulation. The saline soils were mainly distributed in Shizuishan County, Pingluo County, Huinong County in the north of Yinchuan and some areas of south Yinchuan. It is concluded that there is potential of salt accumulation in soils in the arid area and it needs further research for establishing management strategies.