対照的な水稲-畑作物輪作体系が易分解性有機炭素の調節を介して温室効果ガス排出を分岐させる—収量とのトレードオフを伴う

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

🔬研究者:輪作体系と土壌炭素画分がメタン排出を制御するメカニズムの実証データを提供する。

🏢実務担当者:農産物調達・サプライチェーン排出削減のため、輪作選択が収量とGHGのトレードオフを生む点を理解できる。

🏛政策担当者:農業由来メタン削減と食料生産の両立を図る政策設計に、輪作奨励の定量的根拠を与える。

Context Optimizing crop rotations is essential for synergistically increasing yield and reducing environmental impacts. However, in rice-dryland crop rotation systems, the underlying mechanisms through which different dry-season crops influence subsequent rice yield and greenhouse gas (GHG) emissions remain to be elucidated. Objective This study aims to clarify the mechanisms by which dry-season crops influence the productivity and GHG emissions of the subsequent rice season, to identify agronomic strategies that balance grain yield and environmental effects. Methods Over three consecutive years (2021–2023), a field experiment was conducted to assess how different dry-season crops affected soil properties, rice productivity, and GHG emissions in the subsequent rice season. Results Four rotation treatments were compared: fallow-rice rotation (FR), wheat-rice rotation (W R ), garlic-rice rotation (GR), and rapeseed-rice rotation (RR). Compared with the FR system, all rice-dryland crop rotation treatments enhanced rice yield by 10.74%–16.97% but also elevated global warming potential (GWP) by 13.96%–35.88%. Among the three rice-dryland crop rotation treatments, W R system exhibited the lowest rice yield (11.00 Mg ha⁻¹), GWP (3247.11 kg CO 2 -eq ha −1 ), and greenhouse gas intensity (GHGI, 0.29 kg CO 2 -eq kg −1 ). In contrast, the GR treatment achieved the highest rice yield (11.80 Mg ha −1 ), GWP (4009.53 kg CO 2 -eq ha −1 ), and GHGI (0.34 kg CO 2 -eq kg −1 ). The RR treatment showed intermediate values, with a yield of 11.77Mg ha −1 , GWP of 3722.73 kg CO 2 -eq ha −1 , and GHGI of 0.32. Methane (CH 4 ) was the predominant GHG, accounting for 95.80% of total GWP. Conclusions The increased labile organic carbon (LOC) in topsoil under GR and RR treatments stimulated methanogenic activity by providing abundant substrates, thereby significantly enhancing CH 4 emissions. In contrast, the W R treatment maintained significantly lower levels of labile organic carbon, effectively suppressing CH 4 emissions. Moreover, the higher nutrient content and organic matter in GR and RR treatments enhanced rice productivity. Implications These findings elucidate the underlying mechanisms through which different dry-season crops modulate soil organic carbon fractions, thereby influencing subsequent rice yield and GHG emissions. Specifically, the W R treatment effectively reduced GHG emissions but at the expense of yield, underscoring a trade-off between environmental sustainability and agricultural productivity.

• openalex https://doi.org/10.1016/j.fcr.2026.110724first seen 2026-09-23 04:57:52