模拟硝田土壤铁和硫的形态转化特征及其影响因素

采用室内培养试验,在确定模拟硝田土壤硫酸钠含量的基础上,观测并探讨落干/淹水状况、有机物质种类与数量对模拟硝田土壤铁和硫形态转化特征的影响。结果表明:全铁(Fet)和游离铁(Fed)受落干/淹水状态和有机物质种类与数量的影响均不显著,而活性铁(Feo)、络合铁(Fep)、亚铁离子(Fe(II))及有效铁(Fea)受淹水及有机物质数量的显著影响,Fe(II)、Fea还受有机物质种类的显著影响;硫形态转化同时受淹水及有机物质种类与数量的影响;土壤铁、硫形态转化一方面通过有机物质与铁、硫的直接作用实现,一方面通过改变土壤氧化还原电位(Eh)及还原性物质总量(TARM)等氧化还原状况实现;铁与硫的形态转化也表现出一定的耦合关系。

Fe and S Transformation Characteristics and Their Influential Factors in Simulated Mirabilite Soil

In an indoor incubation experiment, we determined the Na2SO4 contents of simulate mirabilite soil, observed and discussed the effect of Drying-Submergence conditions and different kinds and quantities of organic substance on transformation of Fe and S in the simulate mirabilite soil. The results show that: (1) Drying-Submergence conditions and organic substance have no significant effect on Fet and Fed. However submergence and the quantities of organic substance have significant effect on Feo, Fep, Fe(II) and Fea. Moreover, Fe(II) and Fea are significantly affected by organic substances as well. (2) Submergence condition and organic substance can both promote the transformation of S in the mirabilite soil. (3) The transformation of Fe and S is realized by direct reaction of organic substance, on the other hand, by changing the conditions of soil redox including Eh and TARM. (4) Besides, transformation between forms of Fe and forms of S exists a coupling relationship in the simulate mirabilite soil.