No-tillage (NT) and the introduction of cover crops, owing to their positive effects on soil organic carbon (SOC) sequestration and crop yields, are potential agricultural practices that both support food security under the new realities of climate change and alleviate greenhouse gas (GHG) emissions. However, the effects of the combination of long-term NT systems and cover crops on non-carbon dioxide (CO₂) emissions and SOC sequestration have not been adequately documented, particularly in East Asia. We conducted a split-plot field experiment involving two tillage systems [NT and moldboard plowing (MP)] and three cover crops, namely, fallow (FA), hairy vetch (HV), and rye (RY). NT had slightly higher soybean yield than MP, although tillage methods and cover crop treatments had no significant effects on soybean yield. Cover crop treatments rather than tillage methods significantly affected methane (CH₄) emissions; under FA and RY treatments, we observed CH₄ uptakes, whereas under HV, we observed CH₄ emissions. In contrast, rather than cover crop treatments, tillage methods affected nitrous oxide (N₂O) emissions. Higher WFPS and soil bulk density under NT resulted in significantly higher annual N₂O emissions than those under MP. However, under NT, the annual SOC sequestration rate significantly increased compared with that under MP, the global warming potential (GWP) caused by CH₄ and N₂O emissions was fully offset by net CO₂ retention under NT. Additionally, treatment under NT reduced net GWP and yield-scaled GWP to a significantly greater degree than did treatment under MP. Treatments under NT with RY cover crop had the lowest net GWP (−2324 kg CO₂ equivalent ha⁻¹ year⁻¹) and yield-scaled GWP (−1037 kg CO₂ equivalent Mg⁻¹ soybean yield). These findings suggest that treatments under NT with cover crop systems—especially RY cover crop—in the long-term organic soybean field maintains sustainable crop production and reduces net GWP and yield-scaled GWP, which will be an effective climate-smart agriculture practice in the humid, subtropical regions prevailing in Kanto, Japan.

由于免耕和覆盖作物的引入对土壤有机碳的固存和作物产量具有积极影响，因此它们是潜在的农业实践，既支持气候变化新现实下的粮食安全并减少温室气体（GHG）排放。但是，长期NT系统和覆盖作物的结合对非二氧化碳（CO ₂）排放和SOC隔离的证据不足，尤其是在东亚。我们进行了分块田间试验，涉及两个耕作系统[NT和mold土犁耕（MP）]和三个覆盖作物，即休耕（FA）、,子（HV）和黑麦（RY）。尽管耕作方法和覆盖作物处理对大豆产量没有显着影响，但NT大豆的产量略高于MP。覆盖农作物而不是耕种方法会严重影响甲烷（CH ₄）的排放；在FA和RY处理下，我们观察到CH ₄吸收，而在HV下，我们观察到CH ₄排放。相反，耕作方法不是覆盖作物，而是影响了一氧化二氮（N ₂O）排放。NT下较高的WFPS和土壤容重导致MP上的年度N ₂ O排放量显着增加。然而，在NT下，SOC的年固存率比MP下显着提高，CH ₄和N ₂ O排放引起的全球变暖潜势（GWP）被NT下的净CO ₂保留量完全抵消。此外，与MP处理相比，NT处理降低了净GWP和产量成比例的GWP明显更大。NT下使用RY覆盖作物的处理的净全球升温潜能值最低（-2324 kg CO ₂当量公顷- ¹年^-1），单产规模全球升温潜能值（−1037 kg CO ₂当量镁）^-1大豆产量）。这些发现表明，在长期有机大豆田中，在NT下采用覆盖作物系统（尤其是RY覆盖作物）进行的处理能够维持可持续的作物生产并降低净GWP和单产规模GWP，这将是一种有效的气候智能型农业实践。日本关东盛行的潮湿亚热带地区。