Liu Churong, Zhang Yushi, Liu Hongrun, Liu Xueqing, Ren Danyang, Wang Ligang, Guan Dahai, Li Zhaohu, Zhang Mingcai
State Key Laboratory of Plant Physiology and Biochemistry, Engineering Research Center of Plant Growth Regulator, Ministry of Education, China Agricultural University, Beijing 100193, China.
Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
Sci Total Environ. 2022 Feb 1;806(Pt 3):151225. doi: 10.1016/j.scitotenv.2021.151225. Epub 2021 Oct 27.
Nitrous oxide (NO) is a pollutant released from agriculture soils following N fertilizer application. N stabilizers, such as N-(n-butyl) thiophosphoric triamide (NBPT) and 3,4-dimethylpyrazole phosphate (DMPP) could mitigate these NO emissions when applied with fertilizer. Here, field experiments were conducted to investigate the microbial mechanisms by which NBPT and DMPP mitigate NO emissions following urea application. We determined dynamic NO emissions and inorganic N concentrations for two wheat seasons and combined this with metagenomic sequencing. Application of NBPT, DMPP, and both NBPT and DMPP together with urea decreased mean NO accumulative emissions by 77.8, 91.4 and 90.7%, respectively, compared with urea application alone, mainly via repressing the increase in NO concentration after N fertilization. Sequencing results indicated that urea application enriched microorganisms that were positively correlated with NO production, whereas N stabilizers enriched microorganisms that were negatively correlated with NO production. Furthermore, compared to urea application alone, NBPT with urea reduced the abundances of genes related to denitrification, including napA/nasA, nirS/nirK, and norBC, resulting in a higher soil NO pool. Conversely, DMPP application, either alone or together with NBPT, decreased the abundance of genes involved in ammonia oxidation and denitrification, including amoCAB, hao, napA/nasA, nirS/nirK, and norBC, and maintained a greater soil NH pool. Both N stabilizers resulted in similar abundances of nirABD-which is related to NO reducers-as when no N fertilizer was applied, which could prevent NO accumulation, consequently mitigating NO emissions. These findings suggest that the high effectiveness of N stabilizers on mitigating NO emissions could be attributed to changes to soil microbial communities and N-cycling functional genes to control the by-product or intermediate products of microbial N-cycling processes in agricultural soils.
氧化亚氮（NO）是农业土壤在施用氮肥后释放的一种污染物。氮稳定剂，如N-（正丁基）硫代磷酸三酰胺（NBPT）和3,4-二甲基吡唑磷酸盐（DMPP），在与肥料一起施用时可以减少这些NO排放。在此，进行了田间试验，以研究NBPT和DMPP减少尿素施用后NO排放的微生物机制。我们测定了两个小麦季的动态NO排放和无机氮浓度，并将其与宏基因组测序相结合。与单独施用尿素相比，NBPT、DMPP以及NBPT和DMPP与尿素一起施用分别使平均NO累积排放量降低了77.8%、91.4%和90.7%，主要是通过抑制施肥后NO浓度的增加。测序结果表明，施用尿素使与NO产生呈正相关的微生物富集，而氮稳定剂使与NO产生呈负相关的微生物富集。此外，与单独施用尿素相比，NBPT与尿素降低了与反硝化作用相关的基因丰度，包括napA/nasA、nirS/nirK和norBC，导致土壤NO库更高。相反，单独施用DMPP或与NBPT一起施用，均降低了参与氨氧化和反硝化作用的基因丰度，包括amoCAB、hao、napA/nasA、nirS/nirK和norBC，并维持了更大的土壤NH库。两种氮稳定剂导致的nirABD（与NO还原器相关）丰度与不施氮肥时相似，这可以防止NO积累，从而减少NO排放。这些发现表明，氮稳定剂在减少NO排放方面的高效性可能归因于土壤微生物群落和氮循环功能基因的变化，以控制农业土壤中微生物氮循环过程的副产物或中间产物。
