松嫩平原苏打盐渍土表层土壤黏粒矿物的组成分析

以松嫩平原内的前郭和大安两地苏打盐渍土表层土壤为供试土壤,采用Rigaku RIX 2000型荧光光谱仪和XRD-7000衍射仪,对土壤黏粒矿物组成进行了分析。结果表明:表层土壤黏粒(<2μm)化学组成均以SiO2、Al2O3和Fe2O3为主,其SiO2/Al2O3>4,土壤风化脱硅作用较弱;土壤黏粒以2∶1型层状铝硅酸盐矿物为主,含有蒙脱石、伊利石-蒙脱石混层矿物、伊利石、伊利石-白云母混层矿物、蛭石、1∶1型层状铝硅酸盐高岭石以及少量2∶1∶1型绿泥石和石英及1.42 nm间层矿物。苏打盐渍土处于风化脱K作用阶段,土壤中混层及间层矿物较多,以蛭石-绿泥石、蒙脱石-绿泥石过渡矿物为主,为二八面体白云母和二八面体蒙脱石混层矿物。水田利用可使土壤黏粒中绿泥石增加,改善苏打盐渍土不良的结构。

Composition analysis of clay minerals from soda saline surface soil in Songhuajiang-Nenjiang plain

Taking the soda saline surface soil of Qianguo and Da an of the Songhuajiang-Nenjiang plain as sample soil,the compositions of the clay mineral of soil were analyzed by using XRF and XRD test methods.The results show that the chemical compositions of clay smaller than 2μm are SiO 2,Al 2O 3 and Fe 2O 3,and the ratio of SiO 2/Al 2O 3 is greater than 4,revealing that weathering desilication is weak.The surface soda saline soil clay mineral compositions are mainly 2∶1 type of layered aluminosilicate minerals consisting of montmorillonite,mixed layer of illite and montmorillonite,illite,mixed layer of illite and muscovite,vermiculite,some 1∶1 type layered aluminosilicate kaolinite,and minor 2∶1∶1 type chlorite,quartz and 1.42 nm interlayer minerals.Soda saline soil is in the stage of weathering and potassium removing.There are many mixed layer and interlayer minerals in the soil,mainly transition minerals e.g.,vermiculite-chlorite and montmorillonite-chlorite,and the mixed layer minerals of octahedral muscovite and octahedral montmorillonite.Paddy field utilization can increase chlorite in soil clay and improve the structure of soda saline soil.