The C/N ratio and phenolic groups of exogenous dissolved organic matter together as an indicator for evaluating the stability of mineral-organic associations in red soil

• Published in: Journal of soils and sediments Vol. 21; no. 2; pp. 821 - 831
• Main Authors: Zhang, Xiaojia, Wang, Yanan, Wen, Jiong, Zhang, Yang, Su, Shiming, Wen, Yunjie, Yan, Mengmeng, Bai, Lingyu, Wu, Cuixia, Zeng, Xibai
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.02.2021; Springer Nature B.V
• Subjects: Analytical methods; Aromaticity; Carbon/nitrogen ratio; Decomposing organic matter; Dissolved organic matter; Earth and Environmental Science; Environment; Environmental Physics; Fertility; Fulvic acids; Humus; Incubation period; Microorganisms; Nutrients; Organic carbon; Organic compounds; Phenolic compounds; Phenols; principal component analysis; Principal components analysis; Redundancy; rice; Rice straw; Sec 1 • Soil Organic Matter Dynamics and Nutrient Cycling • Research Article; Soil; Soil aggregates; Soil analysis; Soil fertility; Soil improvement; Soil microorganisms; Soil Science & Conservation; soil separates; Soil stability; Soil structure; Soils; Spectroscopy; Stability analysis; Straw; Mineral-organic associations; Soil combined humus; Dissolved organic matter; Organic functional groups; Red soil
• ISSN: 1439-0108; 1614-7480
• DOI: 10.1007/s11368-020-02874-y

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 (SUVA 254 ), 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.