Purpose

Mineral-organic associations (MOAs) are the basic structural units of soil aggregates and are important reservoirs of nutrients for plants and soil microorganisms, determining the soil structure and fertility. However, the influence of exogenous dissolved organic matter (DOM) chemistry on the stability of MOAs is rarely reported.

Materials and methods

We first characterized different exogenous DOM through elemental analysis and spectroscopy analysis technologies. Then, a chamber incubation experiment was conducted with DOM addition concentration at 3 g C kg⁻¹ red soil. Principal component analysis, redundancy analysis, and the partial least squares path model were used to better understand the effect of exogenous DOM chemistry on the stability of MOAs.

Results and discussion

The addition of DOM into the red soil significantly increased not only the organic carbon both in the bulk soil and the soil heavy fraction, but also the soil combined humus and the soil mineral-organic compound quantity. Moreover, the rice straw-derived DOM had the best effect on improving the soil mineral-organic compound quantity/degree (additional), followed by the animal-derived DOM, while the fulvic acid increased it the least. The ratios of elements (C/N ratio, O/C ratio, and H/C ratio), aromaticity (SUVA₂₅₄), and phenolic C content of exogenous DOM had positively significant contributions to the stability of MOAs.

Conclusions

The rice straw-derived DOM had the greatest enhancement on the stability of the MOAs for its higher C/N ratio and phenolic groups content, so the exogenous DOM characteristics could be as an indicator in predicting the stability of the MOAs and evaluating the soil fertility.

中文翻译：

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C / N比和外源溶解有机物的酚基一起作为评价红壤中矿物-有机缔合稳定性的指标

目的

矿物-有机缔合（MOA）是土壤团聚体的基本结构单位，是植物和土壤微生物的重要养分库，决定着土壤的结构和肥力。但是，很少报道外源溶解有机物（DOM）化学对MOA稳定性的影响。

材料和方法

我们首先通过元素分析和光谱分析技术来表征不同的外源DOM。然后，在3g C kg ^-1红壤中以DOM添加浓度进行室培养实验。使用主成分分析，冗余分析和偏最小二乘路径模型可以更好地了解外源DOM化学对MOA稳定性的影响。

结果与讨论

在红壤中添加DOM不仅显着增加了块状土壤和土壤重组分中的有机碳，而且还增加了腐殖质和土壤矿物有机化合物的含量。此外，稻草来源的DOM对改善土壤矿物-有机化合物的量/度（附加）具有最佳的效果，其次是动物来源的DOM，而富里酸的增加最少。外源DOM的元素比率（C / N比，O / C比和H / C比），芳香性（SUVA ₂₅₄）和酚类C含量对MOA的稳定性具有积极的影响。

结论

稻草来源的DOM由于其较高的C / N比和酚基含量而对MOA的稳定性有最大的增强，因此外源DOM特性可以作为预测MOA稳定性和评价土壤肥力的指标。 。