The accumulation of microbially derived carbon under long-term organic matter addition is related to microbial carbon use and acquisition

Unofficial AI-generated summary based on the public title and abstract. Not an official translation.

🔬研究者:Provides mechanistic understanding of microbial carbon use efficiency in soil carbon sequestration.

🏢実務担当者:May inform agricultural practices for soil carbon enhancement, but requires local validation.

🏛政策担当者:Supports soil organic carbon management as a climate mitigation tool, but not directly policy-ready.

土壌微生物由来の炭素は土壌炭素隔離に不可欠であるが、耕地における有機物施用下でのその動態は、微生物の炭素・窒素・リンの代謝機能間の相互作用と、土壌環境変化に対するそれらの多様な応答に主に起因して、依然として十分に理解されていない。ここでは、長期圃場試験に基づき、化学肥料と稲わらまたは堆肥の併用施用が土壌中の微生物由来炭素蓄積に及ぼす影響を調査した。微生物の炭素利用効率と炭素獲得能を定量するために18O-H2Oトレーサー法と土壌細胞外酵素を用い、微生物の炭素・窒素・リン機能遺伝子を決定するためにメタゲノムシーケンシングを実施し、微生物代謝と微生物由来炭素との間の本質的な関係を解明することを目的とした。結果は、化学肥料処理と比較して、稲わらまたは堆肥を併用した化学肥料処理は両方とも微生物由来炭素の蓄積を有意に増加させたことを示した。さらに、微生物由来炭素は微生物炭素利用効率と有意に正の相関を示したが、炭素獲得能とは負の相関を示した。具体的には、稲わらまたは堆肥を併用した化学肥料処理は微生物炭素利用効率を増加させたが炭素獲得能を低下させ、それにより微生物の代謝パターンを「高分解」状態から「高利用」状態へと移行させ、これは微生物由来炭素の保持と関連していた。相関分析は、微生物炭素利用効率が硝酸性窒素、SOCと有意に正の相関を示し、微生物の炭素・窒素機能遺伝子（例えば、二糖代謝、異化的硝酸還元、および窒素固定に関与するもの）とは負の相関を示した一方、炭素獲得能は逆のパターンを示したことを示した。特に、稲わらまたは堆肥を併用した化学肥料処理下での硝酸性窒素とSOCの増加は、微生物の資源制限を効果的に緩和し、窒素および炭素機能遺伝子の両方と負の相関を示した。これらの知見は、微生物代謝機能、炭素獲得と利用の間の関係を調節する際の窒素と炭素の可利用性の役割を解明し、有機物施用下での微生物由来炭素蓄積を支配するメカニズムの理解を向上させる。

AI 翻訳（deepseek-v4-flash）。 正確を期す場合は下の原文を参照してください。

Soil microbially derived carbon is essential for soil carbon sequestration, yet its dynamics under organic matter addition in croplands remain poorly understood, largely owing to the interactions among microbial carbon, nitrogen, and phosphorus metabolic functions and their divergent responses to soil environmental changes. Here, based on a long-term field experiment, we investigated the effects of combined application of chemical fertilizer with straw or manure on microbially derived carbon accumulation in soils. The 18 O-H 2 O tracer method and soil extracellular enzyme were used to quantify microbial carbon use efficiency and carbon acquisition capacity, and metagenomic sequencing was performed to determine microbial carbon, nitrogen and phosphorus functional genes, aiming to unravel the intrinsic relationship between microbial metabolism and microbially derived carbon. The results showed that, compared to the chemical fertilizer treatment, the chemical fertilizer treatments with straw or manure both significantly increased the accumulation of microbially derived carbon. Furthermore, the microbially derived carbon was significantly positively correlated with microbial carbon use efficiency but negatively correlated with carbon acquisition capacity. Specifically, chemical fertilizer treatments with straw or manure increased microbial carbon use efficiency but reduced carbon acquisition capacity, thereby shifting the microbial metabolic pattern from a “high decomposition” state to a “high utilization” state, which associated with the retention of microbially derived carbon. Correlation analysis showed that microbial carbon use efficiency was significantly positively correlated with nitrate nitrogen, SOC but negatively with microbial carbon and nitrogen functional genes (e.g., those involved in disaccharide metabolism, dissimilatory nitrate reduction, and nitrogen fixation), whereas carbon acquisition capacity exhibited the opposite pattern. Especially, the increased nitrate nitrogen and SOC under chemical fertilizer with straw or manure effectively alleviated microbial resource limitation and were negatively correlated with both nitrogen and carbon functional genes. These findings elucidate the role of nitrogen and carbon availability in regulating the relationships among microbial metabolic functions, carbon acquisition and utilization, improving our understanding of the mechanisms governing microbial-derived carbon accumulation under organic matter addition.

• openalex https://doi.org/10.1016/j.geoderma.2026.117896first seen 2026-06-18 05:21:50