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題 目：Carbon sequestration though straw amendment: multi-pool dynamics within soil organic carbon 導讀 秸稈還田被廣泛用于改善土壤結構穩定性并增加土壤有機碳（SOC）庫。然而，由于SOC成分復雜，不同碳庫對秸稈還田的響應及其相互關系仍不清楚。本研究通過對3206組配對數據進行元分析，評估了秸稈還田對功能性碳庫（顆粒有機碳 POC 和礦物結合有機碳 MAOC）、團聚體相關碳庫（大團聚體碳、小團聚體碳以及粉砂–黏粒結合碳）以及微生物碳庫（微生物生物量碳 MBC 和微生物殘體碳）的影響。
 結果表明，與對照相比，秸稈還田使SOC增加了 16 ± 0.9%，其中POC和MAOC分別增加了 33 ± 3.2% 和 9.6 ± 2.6%。POC的累積與更多的秸稈碳輸入和更高的水解酶活性相關，并且與大團聚體碳的關系更為密切，這表明團聚體結構的改善在秸稈還田下SOC增加中起關鍵作用。在前5年內，POC、大團聚體碳及其占SOC的比例均有所增加，但在10年以上的長期處理中則有所下降，說明碳最初進入周轉速率較快的碳庫，并可能在時間推移中經歷了多輪微生物分解循環。五年以上秸稈還田下微生物殘體碳的增加，進一步證明了微生物對碳的轉化與穩定作用，從而延長了碳在土壤中的駐留時間。
Fig. 1. Distribution of experimental sites used in the meta-analysis of soil organic carbon pools response to straw amendment. Numbers in brackets show the number of data pairs. The Left Inset represents the distribution of studies sites within main biomes. POC, particulate organic carbon; MAOC, mineral-associated organic carbon; MacroAC, macroaggregate-associated carbon; MicroAC, microaggregate-associated carbon; SCSOC, silt–clay associated carbon; DOC, dissolved organic carbon; MBC, microbial biomass carbon; MNC, microbial necromass carbon. Fig. 2. Effects of straw amendment on total SOC (a), functional pools (b: POC and MAOC), aggregate-associated pools (c: MacroAC, MicroAC and SCSOC), microbial pools (d: MBC and MNC), DOC, and their contributions to SOC (e, f, g) in the croplands globally. Error bars represent the 95% confidence intervals (CIs), and the effect size is considered significant when the CIs do not overlap with zero. SOC, soil organic carbon; POC, particulate organic carbon; MAOC, mineral-associated organic carbon; MacroAC, macroaggregate-associated carbon; MicroAC, microaggregate-associated carbon; SCSOC, silt–clay associated carbon; DOC, dissolved organic carbon; MBC, microbial biomass carbon; MNC, microbial necromass carbon.
 Fig. 3. Relationships between the response of carbon pools (a, b, c) to straw amendment and SOC, and the interrelationships among these fractions showing physico-chemical protection using phase diagrams (d, e, f). Linear regressions are shown as straight lines. Asterisks indicate significant differences (***p < 0.001, **p < 0.01, *p < 0.05). Regression lines of phase diagrams (d, e, f) were calculated on the basis of the significant regressions in (a, b, c). POC, particulate organic carbon; MAOC, mineral-associated organic carbon; MacroAC, macroaggregate-associated carbon; MicroAC, microaggregate-associated carbon; SCSOC, silt–clay associated carbon; DOC, dissolved organic carbon; MBC, microbial biomass carbon; MNC, microbial necromass carbon; SOC, soil organic carbon.Fig. 4. The responses of oxidative C-degrading EEAs, hydrolytic C-degrading EEAs, N-degrading EEAs to straw amendment (a) and their relationships with the SOC (b), and enzymatic reaction showing the relationship between hydrolytic enzymatic activities and POC (c). Error bars represent the 95 % confidence intervals (CIs), and the effect size is considered significant when the CIs do not overlap with zero. The closed and open symbols indicate significant and non-significant effects, respectively. Linear regressions are shown as straight lines, with dashed lines indicating insignificant correlation. Asterisks indicate significant differences (***p < 0.001, **p < 0.01, *p < 0.05). EEAs, extracellular enzyme activities; BG, β-1,4-glucosidase; BX, β-1,4-xylosidase; CBH, β-D-cellobiosidase; POX, phenol oxidase; PER, peroxidase; NAG, β-N-acetylglucosaminidase; LAP, Leucine aminopeptidase; POC, particulate organic carbon; SOC, soil organic carbon.Fig. 5. Prediction of the response of functional, physical, microbial pools and DOC to straw amendment by climate variables (MAT, MAP, aridity), initial soil properties (SOC, TN, C/N, pH) and management (C_input, duration) based on random forest analysis. The mean square error (MSE) indicates the importance of predictors. POC, particulate organic carbon; MAOC, mineral-associated organic carbon; MacroAC, macroaggregate-associated carbon; MicroAC, microaggregate-associated carbon; SCSOC, silt–clay associated carbon; DOC, dissolved organic carbon; MBC, microbial biomass carbon; MNC, microbial necromass carbon; MAT, mean annual temperature; MAP, mean annual precipitation; AI, aridity index; SOC, soil organic carbon; TN, total nitrogen; C/N: the ratio of soil carbon to nitrogen. Fig. 6. Effects of experiment duration on functional pools (a), aggregate-associated pools (b), microbial pools, DOC (c), and their contributions to SOC (d, e, f). The error bars represent 95% confidence intervals (CIs). The closed and open symbols indicate significant and non-significant effects, respectively. The gray number represents the number of observations. POC, particulate organic carbon; MAOC, mineral-associated organic carbon; MacroAC, macroaggregate-associated carbon; MicroAC, microaggregate-associated carbon; SCSOC, silt–clay associated carbon; DOC, dissolved organic carbon; MBC, microbial biomass carbon; MNC, microbial necromass carbon; SOC, soil organic carbon.Fig. 7. Summary of the effects of straw amendment on carbon sequestration by physical, chemical and biological protection in cropland ecosystems. The numbers in parentheses indicate average effects (%) of straw amendment on variables. The symbol “+” indicate positive effects, and the symbol “?” indicate negative effects. The gray letters indicate no significant difference. SOC, soil organic carbon; POC, particulate organic carbon; MAOC, mineral-associated organic carbon; MacroAC, macroaggregate-associated carbon; SCSOC, silt–clay associated carbon; DOC, dissolved organic carbon; MBC, microbial biomass carbon; MNC, microbial necromass carbon.導讀 本研究在全球尺度上揭示了秸稈還田對SOC多類碳庫及其穩定性的作用機制，強調了在農田管理中采用多碳庫策略的重要性。 
原文鏈接：
https://www./science/article/pii/S001670612500312X 供 稿：劉文勝
編 輯：羅 晴 責任編輯：劉文勝 韓守威 Conservation Agriculture Group
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