442Earth Sciences Building, Department of Renewable Resources, University of Alberta, Edmonton, T6G 2E3, Canada.
J Environ Manage. 2021 Oct 1;295:113080. doi: 10.1016/j.jenvman.2021.113080. Epub 2021 Jun 26.
Unprecedented increases in agricultural nitrous oxide (NO) emissions in recent years have caused substantial environmental pollution that leads to ozone depletion and global warming. Application of biochar and/or nitrification inhibitors (NIs) has the potential to reduce NO emissions; however, it is not clear how biochar application may affect the efficacy of NI in reducing nitrification rates, soil enzyme activities, and NO emissions under different soil moisture regimes. We conducted a 60-day laboratory incubation experiment to study the effects of manure biochar and nitrapyrin (as a NI) on NO emissions from a urea fertilized soil with either 60 (low) or 80% (high) water-filled pore space (WFPS). Nitrification rates were significantly affected by biochar × NI × WFPS and biochar × WFPS interactions. Biochar initially increased and then decreased the rates, resulting in 45.2 and 26.6% (P < 0.001 for both) overall reductions in low and high WFPS, respectively while NI reduced the rates only in the first 10 days at 60% WFPS. Biochar decreased (P < 0.001) and NI increased (P = 0.007) β-1,4-N-acetyl glucosaminidase activities while urease activities were increased (P < 0.001) by biochar across WFPS. Biochar had significant interaction with NI in cumulative NO emissions with the efficacy of NI being reduced when co-applied with biochar. Cumulative NO emissions were greater at high than at low WFPS; the emissions were decreased by biochar at 60% WFPS and NI at both 60 and 80% WFPS. We conclude that biochar reduces efficacy of nitrapyrin in mitigating NO emissions and their effects on net nitrification rates, enzyme activities and NO emissions are dependent on soil moisture level.
近年来，农业一氧化二氮（NO）排放的空前增加导致了严重的环境污染，从而导致臭氧消耗和全球变暖。生物炭和/或硝化抑制剂（NIs）的应用有可能减少 NO 排放；然而，目前尚不清楚生物炭的应用如何影响 NI 在降低硝化速率、土壤酶活性和不同土壤水分条件下 NO 排放方面的效果。我们进行了一项为期 60 天的实验室孵化实验，以研究粪肥生物炭和硝呋吡嗪（作为 NI）对施尿素的土壤中 60%（低）或 80%（高）水充满孔隙空间（WFPS）下的 NO 排放的影响。硝化速率受到生物炭×NI×WFPS 和生物炭×WFPS 相互作用的显著影响。生物炭最初增加然后减少了速率，导致低 WFPS 和高 WFPS 分别总体减少了 45.2%和 26.6%（两者均 P<0.001），而 NI 仅在 WFPS 为 60%的前 10 天降低了速率。生物炭降低（P<0.001）和 NI 增加（P=0.007）β-1,4-N-乙酰葡萄糖胺酶活性，而脲酶活性在整个 WFPS 范围内均因生物炭而增加（P<0.001）。生物炭与 NI 在累积 NO 排放方面具有显著的相互作用，当与生物炭共同施用时，NI 的效果降低。在高 WFPS 下，累积 NO 排放大于低 WFPS；在 WFPS 为 60%时，生物炭减少排放，在 WFPS 为 60%和 80%时，NI 减少排放。我们得出结论，生物炭降低了硝呋吡嗪在减轻 NO 排放方面的效果，并且它们对净硝化速率、酶活性和 NO 排放的影响取决于土壤水分水平。
