阿拉善左旗土壤盐分空间变异特征研究

Study on Spatial Variability of Soil Salinity in Alxa Zuoqi

为了获得内蒙古自治区阿拉善左旗土壤盐分空间变异特征,本研究以阿拉善左旗为研究区域,以实地调查采样数据为依据,运用普通克里格法和径向基函数方法探讨研究区土壤盐分的空间分布特征,根据两种方法在土壤盐分空间分布及插值精度等方面对比分析,获得适合评价研究区土壤盐分空间变异特征的研究方法。研究表明:阿拉善左旗土壤盐分具有强烈的空间自相关性。土壤盐分空间格局上表现为西南部及北部高,东南部及中部低的趋势。土壤盐分剖面特征表现出明显的区域性,研究区北部呈现底聚性,西南部及东部突出部分呈现为表聚性的剖面特点。克里格法与径向基函数法均适用于阿拉善左旗土壤盐分的空间特征解译,精度验证表明克里格法更适合于对研究区土壤盐分空间变异的探讨。研究区0~20 cm和20~40 cm两个土层中分别有97.72%与99.89%的土壤遭受不同程度的盐渍化危害,各土层中中度盐渍化土壤面积占比例最大,其次为重度盐渍化土壤和轻度盐渍化土壤,盐土有一定比例的分布。因此,需采取有效的治理措施对阿拉善左旗土壤盐渍化加以防控与治理。

The spatial variability of soil salinity was studied using the methods Ordinary Kriging(OK)and Radial Basis Function(RBF)in Alxa Zuoqi of Inner Mongolia,and the optimal method of assessment on the spatial variability of soil salinity was determined by comparing OK and RBF on the spatial distribution trend of soil salinity and interpolation accuracy.The results showed that soil salinity had a strong spatial autocorrelation in Alxa Zuoqi.Soil salinity of high levels was mainly distributed in the south-west and north areas of Alxa Zuoqi,while the low level was mainly in the southeast and central areas.Profile distribution of soil salinity showed obvious regional characteristics,the salinity in bottom soil was the greatest in north area and the salinity in surface soil was the greatest in southwest and eastern areas.OK method had better interpolation accuracy and spatial distribution than RBF method.The 97.72% and 99.89% of areas suffered from different degrees of salinization in 0–20 cm and 20–40 cm layers.The proportion of moderately salinity was the largest in the study area,followed by heavy salinity and slightly salinity.There was a certain proportion of solonchak soil in Alxa Zuoqi.The above results indicate that the effective measures should be taken to prevent and control soil salinization in in Alxa Zuoqi.