土壤藻结皮对高镉农田表层土壤的改良作用研究

Improvement Effect of Soil Algal Crust on the Surface Soil of High Cadmium Farmland

为探索高镉农田土壤的环境友好型改良方法,利用镉污染土壤中筛选的丝状蓝藻培植土壤藻结皮,在土壤藻结皮发育过程中通过测定土壤表层以下0~7cm各分层土壤的pH值以及土壤中有机质、碱解氮含量和镉的吸附量,研究了土壤藻结皮对高镉农田表层土壤的改良作用。结果表明:人工土壤藻结皮层的生物量在80d内从0.03mg/g DWSAC(干重藻结皮)增加至0.73mg/g DWSAC;藻结皮层土壤中有机质含量从22.6g/kg增加至29.6g/kg;pH值从6.24增加至7.02,碱解氮含量从126 mg/kg增加至214 mg/kg;土壤初始镉含量为2.53 mg/kg,表层0~0.5cm土壤中镉的吸附量达到0.55mg/kg,说明土壤藻结皮能够有效改善高镉农田表层土壤环境。该研究结果可为镉污染农田土壤的生物修复提供理论依据。

In order to explore an environment-friendly improvement method of high cadmium farmland soil,we screen a soil filamentous cyanobacterium from cadmium contaminated soil to cultivate soil algal crust.During the development of algal crust,we measure the pH,organic matter,available nitrogen and cadmium adsorption capacity in each soil layer of 0-7cm below the soil surface.This paper studies the improvement effect of soil algal crust on the surface soil of high cadmium farmland.The result shows that the biomass of algal crust increases from 0.03mg/g DWSAC(dry weight soil algal crust)to 0.73mg/g DWSAC in 80 days,the soil organic matter content increases from 22.6g/kg to 29.6g/kg,pH increases from 6.24to 7.02,and available nitrogen increases from 126mg/kg to 214mg/kg.The initial cadmium content in soil is 2.53mg/kg,and the adsorption capacity of cadmium in 0-0.5cm soil is 0.55mg/kg.Hence,the soil algal crust can improve the topsoil environment effectively and remove cadmium from high cadmium content farmland.The study may provide theoretical reference for bioremidiation of cadimium contaminated farm-land soil.