Effects of tillage patterns and stover mulching on N2O production, nitrogen cycling genes and microbial dynamics in black soil.
Effects of tillage patterns and stover mulching on N2O production, nitrogen cycling genes and microbial dynamics in black soil.
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DOI：
10.1016/j.jenvman.2023.118458
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发表时间：
2023-06
影响因子：
8.7
通讯作者：
Da-Cheng Hao;Xing-Yuan Su;Hong-tu Xie;Xuelian Bao;Xudong Zhang;Lian-feng Wang
中科院分区：
文献类型：
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作者：
Da-Cheng Hao;Xing-Yuan Su;Hong-tu Xie;Xuelian Bao;Xudong Zhang;Lian-feng Wang
秸秆覆盖免耕对秸秆资源的合理利用和耕地质量的提高具有重要意义，对保障地下水、粮食和生态系统安全具有深远影响。然而，耕作方式和秸秆覆盖对土壤氮素周转的影响仍然是难以捉摸的。基于2007年以来东北软土区长期保护性耕作田间试验，采用鸟枪法宏基因组测序和微宇宙培养技术，结合理化分析、炔抑制分析等方法，研究了免耕和秸秆覆盖对农田土壤氮素排放和微生物氮循环基因的调控机制。与常规耕作相比，秸秆覆盖显著降低了N2 O的排放，但CO2排放量没有显著降低，其中秸秆覆盖33%时的效果最为显著，且秸秆覆盖33的硝态氮排放量高于其他覆盖量。秸秆覆盖与较高的全氮，土壤有机碳和pH值。AOB（氨氧化细菌）-氨单加氧酶亚基A（氨单加氧酶亚基A）的丰度大幅增加秸秆覆盖，而反硝化基因的丰度在大多数情况下减少。在炔抑制条件下，耕作方式、处理时间、气体条件及其交互作用对N2 O排放和氮素转化有显著影响。在CT、NT 0（无覆盖）和NT 100（全覆盖）条件下，氨氧化细菌对N2 O产生的相对贡献显著高于氨氧化古菌。不同的耕作模式与不同的微生物群落组成，虽然NT 100是更接近CT比NT 0。与CT相比，NT 0和NT 100的微生物群落共生网络更加复杂。我们的研究结果表明，保持少量秸秆覆盖可以调节土壤氮素周转，以有效地提高土壤健康和再生农业，并应对全球气候变化。
Stover-covered no-tillage (NT) is of great significance to the rational utilization of stover resources and improvement of cultivated land quality, and also has a profound impact on ensuring groundwater, food and ecosystem security. However, the effects of tillage patterns and stover mulching on soil nitrogen turnover remain elusive. Based on the long-term conservation tillage field experiment in the mollisol area of Northeast China since 2007, the shotgun metagenomic sequencing of soils and microcosm incubation were combined with physical and chemical analyses, alkyne inhibition analysis to elucidate the regulatory mechanisms of NT and stover mulching on the farmland soil nitrogen emissions and microbial nitrogen cycling genes. Compared with conventional tillage (CT), NT stover mulching significantly reduced the emission of N2O instead of CO2, especially when 33% mulching was adopted, and correspondingly the nitrate nitrogen of NT33 was higher than that of other mulching amounts. The stover mulching was associated with higher total nitrogen, soil organic carbon and pH. The abundance of AOB (ammonia-oxidizing bacteria)-amoA(ammonia monooxygenase subunit A) was substantially increased by stover mulching, while the abundance of denitrification genes was reduced in most cases. Under alkyne inhibition, the tillage mode, treatment time, gas condition and interactions between them noticeably influenced the N2O emission and nitrogen transformation. In CT, NT0 (no mulching) and NT100 (full mulching), the relative contribution of AOB to N2O production was markedly higher than that of ammonia oxidizing archaea. Different tillage modes were associated with distinct microbial community composition, albeit NT100 was closer to CT than to NT0. Compared with CT, the co-occurrence network of microbial communities was more complex in NT0 and NT100. Our findings suggest that maintaining a low-quantity stover mulching could regulate soil nitrogen turnover toward proficiently enhancing soil health and regenerative agriculture, and coping with global climate change.