2026-10-07T07:20:03Z https://api.figshare.com/v2/oai

oai:figshare.com:article/32786574 2026-09-23T08:29:23Z category_26983 category_26986 item_type_3 month_year_09_2026

<b>Organic acids reconfigure microbial carbon-processing potential in biochar-amended Moso bamboo forest soil</b> Zhenhui Jiang (18627298) Caixian Tang (9477536) Shaobo Zhang (574000) Tida Ge (22798043) Yu Luo (277978) Junjie Lin (8379594) Bing Yu (22118426) Yanjiang Cai (22118430) Yongfu Li (15420236) Soil biology Soil chemistry and soil carbon sequestration (excl. carbon sequestration science) root exudates contribute Carbon processing water-extractable organic carbon (WEOC) <p dir="ltr">1. Root-derived low-molecular-weight organic acids can regulate microbial carbon (C) processing by serving as C substrates and modifying soil physicochemical interactions. However, it remains unclear whether chemically distinct organic acids elicit coordinated responses in fungal-to-bacterial representation, functional-gene potential and enzyme activity in biochar-amended soils.</p><p dir="ltr">2. We conducted a 56-day incubation study using Moso bamboo forest soil with or without maize-straw biochar and with no organic acid or an equal-C addition of citric, malic or oxalic acid. We measured microbial biomass, bacterial and fungal gene-copy abundances, abundances of C-cycling functional genes, potential enzyme activities and soil properties. Functional-gene and enzyme responses were further summarised using a functional pathway balance index (FPBI) and a decomposition-to-fixation activity index (DEAI), respectively.</p><p dir="ltr">3. Biochar consistently suppressed hydrolytic enzyme activities and increased RubisCO-related activity, shifting the measured functional profile away from decomposition-related activity, while not significantly altering the fungal-to-bacterial gene-copy ratio (F/B) in the no-acid control. In the absence of biochar, all three organic acids increased microbial biomass, cellulose-degradation gene abundances and selected hydrolytic activities at day 14, but did not produce a consistent shift in F/B. In biochar-amended soils, responses became strongly acid- and function-specific. By day 56, relative to biochar alone, malic acid decreased F/B but increased FPBI, whereas citric acid increased cellulose-degradation gene abundances despite lower cellobiohydrolase activity. By day 56, the organic-acid effect remained significant for FPBI but not for DEAI, indicating that acid effects persisted more clearly in functional-gene potential than in the enzyme-activity profile.</p><p dir="ltr">4. Organic-acid-specific decoupling among fungal-to-bacterial representation, functional-gene potential and enzyme activity indicates that organic-acid chemistry modulates microbial C-processing responses to biochar.</p> 2026-09-23T08:29:23Z Dataset Dataset 10.6084/m9.figshare.32786574.v2 https://figshare.com/articles/dataset/_b_Organic_acids_reconfigure_biochar-mediated_carbon_decomposition_fixation_balance_in_subtropical_forest_soils_b_/32786574 CC BY 4.0