天津市塘沽区不同土地利用状况下土壤盐分变化特征

Soil Salinity Variation Characteristics under Different Land Use in the Tanggu Region of Tianjin

以天津塘沽区农田、菜地、果园、湿地、人工草地5种土壤利用类型为研究对象,对不同类型土壤中盐分组成和含量进行分析比较。结果表明,该研究区表层土壤总体含盐量较高,且盐渍化程度差异较大。研究区内土样61%为盐土,11%重度为盐渍化,11%为中度盐渍化,18%为轻度盐渍化。土壤盐渍化类型主要为氯化物(占68%)、氯化物-硫酸盐(占25%)和硫酸盐-氯化物(占7%)。在不同土地利用条件下,农田、菜地、果园和人工草地中总盐分含量较低,而湿地中的较高。土壤中水溶性阴离子表现为湿地Cl-比例最高、菜地SO42-比例最高及果园中HCO3-比例最高的特征。5种土地利用类型中,Na+含量明显大于K+,而Ca2+与Mg2+含量相近。总体上表现出湿地Na+比例最高,果园K+比例最高的特征。

In this study,soil samples were collected from different land use types,including farmlands,vegetable lands,orchards,wetlands,and artificial lands,in the Tanggu Region of Tianjin.The result shows that salt compositions in the top layer of soils were high contents,and had a quite different salinity levels.61% of soil samples were saline soils,11% strongly salinized,11% moderately salinized,and 18% slightly salinized.The types of soil salinization were mainly chloride accounting for 68%,chloride-sulfate accounts for 25%,and sulfate-chloride accounts for 7%.Under the different land use types,the total soil contents in the farmlands,vegetable lands,orchards,artificial lands were low levels but high content in the wetlands.The highest proportion of water-soluble anion was Cl-in the wetlands,SO42-in vegetable lands,and HCO3-in orchard lands.In five land use types,Na＋ was significantly greater than K＋,and the content of Ca2＋ and Mg2＋ was similar.In generally,the highest proportion of Na＋ was shown in wetlands,and the highest proportion of K＋ in orchard lands.