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本文以实验室模拟试验,验证了新围垦的盐化水稻土中黑泥层的形成过程。试验证明,即使淋洗液中Na_2SC_4浓度低至0.05％,只要有足够的能源和强烈的还原条件(Eh-100—200mv),很易产生黑泥层。黑泥层中含有大量的Fe~(2+)和S~(2-),这两种离子含量的平均克离子比,接近于FeS的分子式。黑泥层形成过程的动态变化显示,在还原初期,渗漏液中有较多的Si和Fe~(2+)淋出,但后期则明显减少;渗漏液的电导率则随着硫酸盐的还原而逐渐降低。在淋洗和还原过程中,土柱中氧化层和还原层的pH趋向减低,还原层降低更多,但渗漏液的pH则随着硫酸盐的还原而升高。因此,在土壤剖面的下部层次有可能出现较高的钠吸附比,并使pH升高。
In this paper, laboratory simulation tests verify the formation of black mud layer in the newly reclaimed salinized paddy soil. Experiments show that, even if the concentration of Na_2SC_4 in the eluent as low as 0.05%, as long as there is sufficient energy and strong reduction conditions (Eh-100-200mv), it is easy to produce black mud layer. The black mud layer contains a large amount of Fe2 + and S2-, the average ion-ion ratio of these two ions is close to the formula of FeS. The dynamic changes of the formation process of the black mud layer showed that there were more Si and Fe ~ (2+) leaching in the leachate during the initial stage of reduction, but decreased significantly in the late stage. The conductivity of the leachate increased with the increase of sulfate Reduction and gradually reduce. During leaching and reduction, the pH of the oxide and reduction layers in the soil column tended to decrease, the reduction layer was reduced more, but the pH of the leachate increased with sulfate reduction. As a result, a higher sodium adsorption ratio is likely to occur at the lower level of the soil profile and the pH is increased.