黄河三角洲县域尺度的盐渍化土壤化学参数特征研究

地处黄河三角洲的山东省垦利县土地资源丰富、土地利用率低,但区域内土壤盐渍化程度高,理化性质空间变异大,严重制约土地的有效开发利用。本研究通过在县域范围内进行面上布点采样及实验室化学分析,系统研究了垦利县县域尺度0~20及20~40 cm土层土壤盐分及其化学参数间的通径关系及土壤盐渍化的空间分异特征。结果表明:调查期间的垦利县0~20 cm土层土壤盐分高于20~40 cm土层,除pH外两层土壤各项化学参数的变异系数都在中等变异以上;影响0~20及20~40 cm两层土壤盐分(EC5:1)的直接土壤化学参数为Cl~–、Na~+、Ca~(2+),4个参数有非常好的线性回归曲线;0~20 cm土层土壤沿海岸线表现出强烈的盐化和钠质化现象,而20~40 cm土层整体上盐分和钠吸附比均小于表层土壤,盐化和钠质化较弱;土壤p H则表现为20~40 cm土层高于0~20 cm土层,其碱化现象较为明显。研究结果为垦利县土壤盐分研究提供可靠的基础数据及经验公式,同时可为垦利县土壤盐渍化治理提供科学依据及理论指导。

On Chemical Parameters Characteristics of Salinity Soil on County Scale in Yellow River Delta

Kenli County, located at Yellow River Delta, has abundant land resources but with low utilization rate due to the serious inhibition of stern soil salinization which leads to great spatial variation of soil physical and chemical properties. This paper studied systematically the path relationships between soil salt and chemical parameters and the spatial variation characteristics of salinity parameters of 0-20 cm and 20-40 cm soils in Kenli County by the methods of field soil sampling and laboratory chemical analysis. The results showed that salinity of 0-20 cm soil was higher than that of 20-40 cm soil. Except for pH, the variation coefficient of the other studied chemical parameters of the two layer soils were all above medium variant. Cl^-, Na⁺ and Ca²⁺ had significant linear correlation with electrical conductivity (EC_5:1), indicating they were the direct influential factors on soil salinity. 0-20 cm soil showed strong salinization and sodication along the costaline, both EC_5:1 and SAR of 20-40 cm soil were less than topsoil, meaning less soil salinization and sodication. pH in 0-20 cm soil was higher than that of 20-40 cm soil, meaning higher alkalization. The above results can provide not only reliable data bases and empirical formula for soil salinity study but also scientific basis and theoretical guidance for soil salinization control in Kenli County.