Lee Hyun Ho, Kim Hanbeen, Park Ye Lim, Horn Marcus A, Kim Jeongeun, Lee Jaehyun, Toyoda Sakae, Yun Jeongeun, Kang Hojeong, Kim Sang Yoon, Ahn Jinho, Hong Chang Oh
Institute for Microbiology, Leibniz University Hannover, Hannover, Germany.
Department of Life Science and Environmental Biochemistry, Pusan National University, Miryang, Republic of Korea.
Glob Chang Biol. 2025 Aug;31(8):e70428. doi: 10.1111/gcb.70428.
Agricultural activities are a significant source of nitrous oxide (NO), accounting for approximately 60% of global emissions, highlighting the urgent need for innovative strategies to mitigate NO emissions. Microbes conserve nearly as much energy with nitrate (NO ) as oxygen (O) respiration under limited O availability. Thus, microorganisms prioritize NO , limiting exploration of alternative electron acceptors (EAs) to inhibit NO emissions through NO respiration in upland arable soils. Current approaches remain insufficient, and the interactions between alternative EA reduction and pathways for NO emissions remain poorly understood. This study evaluated oxidized iron, manganese, and sulfate as alternative EAs to reduce NO emissions, along with the effects of zero-valent metals (ZVMs). Metal sulfates (MSs) significantly minimized NO emissions by inhibiting denitrification rather than altering nitrification in microcosms, as supported by isotope mapping and inorganic nitrogen concentrations. Among others, putative complete denitrifiers, NO reducers, and sulfate reducers were stimulated, whereas ZVMs stimulated NO emissions and 16S rRNA gene abundance. Moreover, the abundance of denitrifier-related genes (nirK, nirS, norB, and nosZ) consistently decreased under MS treatments, while dsrA mRNA abundance significantly increased. Sulfate (SO ) addition reshaped the soil microbial community by enriching sulfur-cycling taxa-including sulfate-reducing and sulfur-oxidizing bacteria-while suppressing nitrifiers such as Nitrospira, potentially disrupting nitrification-denitrification coupling. Ureibacillus thermosphaerius, harboring genes for denitrification and SO reduction, increased under MS treatment. These shifts likely redirected electron flow toward SO respiration, reducing NO utilization and contributing to NO mitigation. Field-based manipulation experiments over 2 years demonstrated the feasibility of MSs in upland arable soils, reducing yield-scaled NO emissions by 21.5% without compromising crop yields. A systematic literature review and meta-analysis revealed that SO application mitigated NO emissions by an average of 9%, with over 70% of observations showing a decreasing trend, underscoring its potential as an effective soil amendment for sustainable agriculture.
农业活动是一氧化二氮（N₂O）的重要排放源，约占全球排放量的60%，这凸显了迫切需要创新策略来减少N₂O排放。在氧气供应有限的情况下，微生物利用硝酸盐（NO₃⁻）呼吸所保存的能量几乎与利用氧气（O₂）呼吸一样多。因此，在旱地耕作土壤中，微生物优先利用NO₃⁻，限制对替代电子受体（EA）的探索，以通过NO₃⁻呼吸抑制N₂O排放。目前的方法仍然不足，替代EA还原与N₂O排放途径之间的相互作用仍知之甚少。本研究评估了氧化态的铁、锰和硫酸盐作为替代EA以减少N₂O排放，以及零价金属（ZVM）的影响。金属硫酸盐（MS）通过抑制反硝化作用而非改变微观世界中的硝化作用，显著减少了N₂O排放，同位素图谱和无机氮浓度也证实了这一点。其中，假定的完全反硝化菌、NO₂⁻还原菌和硫酸盐还原菌受到刺激，而ZVM则刺激了N₂O排放和16S rRNA基因丰度。此外，在MS处理下，与反硝化作用相关的基因（nirK、nirS、norB和nosZ）的丰度持续下降，而dsrA mRNA丰度显著增加。添加硫酸盐（SO₄²⁻）通过富集参与硫循环的类群（包括硫酸盐还原菌和硫氧化菌）重塑了土壤微生物群落，同时抑制了诸如硝化螺旋菌等硝化菌，可能破坏了硝化-反硝化耦合。在MS处理下，具有反硝化作用和SO₄²⁻还原基因的嗜热球形脲芽孢杆菌数量增加。这些变化可能将电子流导向SO₄²⁻呼吸，减少NO₃⁻的利用并有助于减轻N₂O排放。为期两年的田间操纵实验证明了MS在旱地耕作土壤中的可行性，在不影响作物产量的情况下，将产量尺度下的N₂O排放量降低了21.5%。一项系统的文献综述和荟萃分析表明，施用SO₄²⁻平均可使N₂O排放量减少9%，超过70%的观测结果显示出下降趋势，凸显了其作为可持续农业有效土壤改良剂的潜力。
