Shifting from conventional tillage to a no-till system can contribute to improving soil carbon sequestration and sustaining crop productivity. However, our understanding of the soil nitrogen (N) process through insights into the no-till effect on soil denitrification remains elusive. Here, we compiled data from 323 observations in 57 studies and quantified the responses of soil denitrification and the size and activity of the denitrifying community to no-till vs. conventional tillage. Across all studies, no-till significantly increased soil denitrification (85%) compared to conventional tillage. The no-till effect on soil denitrification was significantly dependent upon N fertilizer management, with a greater increase with N fertilization than without (101 vs. 46%). The increased soil denitrification under no-till was attributed to increases in the size and activity of the denitrifying community. On average, the potential denitrification activity, the total number of denitrifiers, and the abundance of denitrifying genes were increased by 66, 116, and 14–70%, respectively, in response to no-till. Our results demonstrate that soil denitrification under no-till leads to increased soil nitrous oxide (N₂O) emission. This is supported by a larger response of soil N₂O emission compared to the total denitrification, together with a significant increase (33%) in the (nirK + nirS)/nosZ ratio under no-till conditions. Therefore, the increased soil denitrification under no-till conditions may have negative impacts on soil N cycling and mitigation of N₂O emission.

从传统的耕作方式转变为免耕方式可以改善土壤碳固存并维持农作物的生产力。然而，我们通过对免耕对土壤反硝化作用的认识，对土壤氮（N）过程的了解仍然难以捉摸。在这里，我们汇总了57项研究中323项观测值的数据，并量化了土壤反硝化的反应以及反硝化群落相对于免耕与常规耕作的规模和活动。在所有研究中，与传统耕作相比，免耕显着增加了土壤反硝化作用（85％）。免耕对土壤反硝化作用的显着依赖于氮肥的管理，氮肥的施用比不施用氮肥的增加更大（101比46％）。免耕法下土壤反硝化作用的增加归因于反硝化群落的规模和活性的增加。平均而言，响应免耕措施，潜在的反硝化活性，反硝化剂的总数和反硝化基因的丰度分别增加了66％，116％和14-70％。我们的结果表明，免耕条件下土壤的反硝化作用会导致土壤一氧化二氮（N₂ O）发射。与全部反硝化相比，土壤N ₂ O排放的响应更大，并且在免耕条件下（nir K +  nir S）/ nos Z比值显着增加（33％），这得到了支持。因此，免耕条件下土壤反硝化作用的增强可能对土壤氮循环和减少N ₂ O排放产生负面影响。