2026-07-02 中国科学院（CAS）
＜関連情報＞
- https://english.cas.cn/newsroom/research-news/202607/t20260703_1175363.shtml
- https://www.sciencedirect.com/science/article/abs/pii/S0301479726016130
熱帯雨林をゴム農園に転換すると、植物リグニンと微生物残渣の蓄積の仕方が変化することで、土壌有機炭素の隔離の様相が変化する Conversion of tropical rainforest to rubber plantations reshapes soil organic carbon sequestration through divergent accrual of plant lignin and microbial residues
Xia Yuan, Xiaoyi Cai, Xiai Zhu, Wenjie Liu
Journal of Environmental Management Available online: 6 June 2026
DOI:https://doi.org/10.1016/j.jenvman.2026.130153
Highlights
- Rainforest conversion reduced SOC, lignin phenols, and amino sugars.
- Lignin phenols and amino sugars increased with rubber plantation age.
- Microbial residues contributed 5.2–9.3 times more to SOC than plant residues.
- Rubber managements need to consider SOC recovery and long-term C persistence.
Abstract
Tropical forests are being destroyed and converted to tree plantations at an alarming rate, with major consequences for soil organic carbon (SOC) cycling. Although mechanistic insights into SOC formation are fundamental to sustainable land management, how forest-to-plantation conversion modulates plant- and microbial-derived SOC remains unclear. Herein, we evaluated SOC sources using lignin phenols and amino sugars as biomarkers and identified their key drivers across a rubber plantation chronosequence (9, 21, and 37 years) established after tropical rainforest conversion in Southwest China. Both lignin phenol and amino sugar concentrations were positively correlated with total SOC and declined significantly with soil depth. Conversion of rainforest to young rubber plantations was associated with marked reductions in SOC (43%), lignin (18%), and amino sugars (7%) across the 0–40 cm profile. However, both biomarker pools followed an increasing trajectory with rubber stand age, likely driven by enhanced plant litter and root inputs together with reduced microbial lignin degradation. Lignin phenols were mainly regulated by plant properties (e.g., root biomass) and abiotic soil factors (e.g., nutrient availability), whereas amino sugar accumulation was more closely linked to microbial attributes. Notably, lower glucosamine:muramic acid ratios in rubber plantations than in rainforest soils suggest a shift in microbial residue composition that may influence the long-term persistence of microbial-derived SOC. Microbial residues contributed 5.2–9.3 times more to SOC than plant-derived C, highlighting the dominant role of microbial pathways in SOC formation. Moreover, rainforest-to-rubber conversion (regardless of stand age) decreased the relative contribution of plant-derived C to SOC while increasing that of microbial-derived C, particularly bacterial residues. Overall, our results indicate that conversion of tropical forest to rubber plantations was associated with substantial shifts in SOC composition, including an initial loss in both plant- and microbial-derived C and a compositional change in the microbial residue pool that may reduce its persistence potential. These findings highlight the need for rubber plantation managements that promote both SOC recovery and long-term persistence of key C components.
