Abstract

Unstable Fe-minerals, which change the color of gley after the sample extraction from soil and make less pronounced the features of gleying in the dry season, are important in hydromorphic soils parallel to stable Fe-minerals conventionally detected in dried soil. Two new parameters are proposed for the additional characteristic of Fe-minerals. The first one—index I—characterizes the interaction of active Fe-minerals with colloids and is determined as I = CEC/Fe_free, where CEC is the cation exchange capacity. The second parameter is the change in the redness of gley after drying (Δа*) according to the CIE–L*a*b* optic system. In iron-enriched reduced gley (Gr) with low I ~ 0.1 and a strong increase in Δа* (≈9) after drying, the green rust is transformed into brown lepidocrocite. During a decrease in humidity, the transformation of reduced gley into oxidized one is accompanied by a rise in Δа* (≈3) and by a change in the composition of the green rust: the transformation of fougerite into trebeurdenite (Fe-ephemer with a higher oxidation rate of iron). When oxidized gley Go with I = 2–8 dries up, a slow increase in Δа* is caused by the inhibition of crystallization of Fe-hydroxides by colloids. In the deferruginated gley (Gdf) with high I = 6–27, the absence of a rise in the red color (Δа* ≈ 0) during drying is probably related to the inactivity of Fe-phyllosilicates.

中文翻译：

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矿质土壤中铁矿物质的转化

摘要

不稳定的Fe矿物在从土壤中提取样品后会改变g色的颜色，而在干燥季节使less味的特征变得不那么明显，在与常规在干燥土壤中检测到的稳定的Fe矿物平行的水溶土中，这一点很重要。提出了两个新的参数来确定铁矿物的附加特性。第一个指标I表征了活性铁矿物与胶体的相互作用，并确定为I = CEC /_不含铁，其中CEC是阳离子交换能力。第二个参数是根据CIE–L * a * b *光学系统，干燥后g色的发红度变化（Δа*）。在低I的富铁还原格里（Gr）干燥后〜〜0.1且Δа*（≈9）显着增加，绿色的锈变成了棕色的锂铁云母。在湿度降低的过程中，还原的g舞转变为氧化的ley舞伴随着Δа*（≈3）的增加以及生铁锈成分的改变：针铁矿转变为黑钙铁矿（Fe-ephemer具有铁的氧化率更高）。当I = 2–8的氧化的Go变干时，由于胶体抑制氢氧化铁的结晶而导致Δа*的缓慢增加。在I = 6–27的高去铁素基g（Gdf）中，干燥过程中红色的升高（Δа*≈0）不存在可能与Fe-页硅酸盐的失活有关。