Global patterns of microbial necromass and soil organic carbon under sustainable agricultural practices: New insights from machine learning

Abstract

Soil microbial necromass carbon (MNC) is an important component of soil organic carbon (SOC) in croplands. Microbial communities contribute over 50% of the SOC in croplands through continuous turnover and the formation of necromass, which is characterized by its large scale and strong persistence. Agricultural production systems are widely influenced by human activities. There is still a lack of understanding regarding key issues such as the dynamics of MNC and SOC under management practices and their global distribution potential. In this study, we combined meta-analysis with machine learning methods, revealed the impact patterns of cropland management on soil MNC components and SOC. The results showed that the MNC storage reached the highest value of 5.93 Mg C ha⁻¹ under the practice of mineral fertilizer combined with manure. The fungal necromass carbon storage in cropland soils is much higher than that of bacterial necromass carbon, which dominates the changes in microbially-derived organic carbon storage. Assessment results of global potential distribution patterns of MNC and SOC storage under management practices based on machine learning indicate that conservation tillage has the highest global carbon storage potential, reaching up to 2.58 Mg C ha⁻¹ yr⁻¹ and 3.55 Mg C ha⁻¹ yr⁻¹. This study emphasizes the impact and importance of soil microorganisms in croplands as a driving force on SOC storage, accurately quantifies their response to management practices, and comprehensively evaluates the application potential of different management practices on a global scale, enhancing our understanding of the relationship patterns between MNC and SOC in agricultural systems.

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Identifiers

DOI

10.5194/egusphere-egu25-4890

Journal

Unknown journal

Year

2025