Long-term cultivation reduces soil carbon storage by altering microbial network complexity and metabolism activity in macroaggregates

• Published in: The Science of the total environment Vol. 930; p. 172788
• Main Authors: Zhang, Shan, Hu, Wanjin, Zhang, Jinting, Yu, Guanjun, Liu, Yizhen, Kong, Zhaoyu, Wu, Lan
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 20.06.2024
• Subjects: CUE; Extracellular enzyme; Network complexity; Paddy soil; SOC; Soil aggregates; CUE; SOC; Paddy soil; Soil aggregates; Network complexity; Extracellular enzyme
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2024.172788

Cultivation alters soil aggregation, microbial compositions and the potential for carbon sequestration in cropland soils. However, the specific effects of long-term cultivation and the underlying mechanisms on soil organic carbon (SOC) storage at different aggregate sizes remain poorly understood. We characterized the dynamics of SOC storage in macroaggregates (>0.25 mm) and microaggregates (<0.25 mm) across four paddy soils successively cultivated for 60, 100, 125, and 150 years. Microbial community compositions, network patterns, enzyme activities and carbon use efficiency (CUE) were examined to elucidate the underlying microbial pathways governing SOC storage. The results showed that prolonged cultivation led to an average reduction of 45 % in SOC storage, particularly in macroaggregates. Partial least squares path modeling revealed that shifts in microorganisms in macroaggregates explained almost 80 % of the variation in SOC storage. Specifically, variations in fungal composition and decreased complexity of microbial interaction networks were strongly correlated with SOC storage. Fungal community and microbial interactions also indirectly affected SOC storage by positively correlating with extracellular enzyme activity. Moreover, bacterial composition indirectly regulated SOC storage by positively correlating with carbon use efficiency. Our findings indicated that the macroaggregate-associated microbial interactions and the metabolism activities had significant implications for SOC sequestration in paddy fields. We suggest that implementation of management practices targeted at improvement of these microbial attributes could enhance agroecosystems sustainability. Solid grey lines represent significant positive effects and dashed lines represent significant negative effects. The thickness of lines indicates the strength of the influence. [Display omitted] •Long-term cultivation accelerated loss of SOC storage primarily in macroaggregates.•Reduced network complexity in macroaggregates was strongly related to soil C loss.•Fungi exert more important control in regulating SOC storage in macroaggregates.•Microbial response to long-term cultivation varied across soil aggregate sizes.