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.