Can fertigation reduce nitrous oxide emissions from wheat and canola fields?

Autor: Chai LL; Department of Renewable Resources, University of Alberta, 442 Earth Sciences Building, Edmonton, Alberta T6G 2EG, Canada., Hernandez-Ramirez G; Department of Renewable Resources, University of Alberta, 442 Earth Sciences Building, Edmonton, Alberta T6G 2EG, Canada. Electronic address: ghernand@ualberta.ca., Dyck M; Department of Renewable Resources, University of Alberta, 442 Earth Sciences Building, Edmonton, Alberta T6G 2EG, Canada., Pauly D; Alberta Agriculture and Forestry, J.G. O'Donoghue Building, 7000-113 Street, Edmonton, AB T6H 5T6, Canada., Kryzanowski L; Alberta Agriculture and Forestry, Lethbridge Research Centre, 5403 1st Ave. South, Lethbridge, Alberta T1J 4B1, Canada., Middleton A; Alberta Agriculture and Forestry, J.G. O'Donoghue Building, 7000-113 Street, Edmonton, AB T6H 5T6, Canada., Powers LA; Alberta Agriculture and Forestry, J.G. O'Donoghue Building, 7000-113 Street, Edmonton, AB T6H 5T6, Canada., Lohstraeter G; Alberta Agriculture and Forestry, Lethbridge Research Centre, 5403 1st Ave. South, Lethbridge, Alberta T1J 4B1, Canada., Werk D; Alberta Agriculture and Forestry, J.G. O'Donoghue Building, 7000-113 Street, Edmonton, AB T6H 5T6, Canada.
Jazyk: angličtina
Zdroj: The Science of the total environment [Sci Total Environ] 2020 Nov 25; Vol. 745, pp. 141014. Date of Electronic Publication: 2020 Jul 21.
DOI: 10.1016/j.scitotenv.2020.141014
Abstrakt: Increasing nitrogen fertilization and irrigation can contribute to nitrous oxide (N 2 O) emissions from agriculture. Relative to the conventional practice of one-pass fertilization with all N applied at crop seeding, this study examined how splitting the total N fertilization into seeding time and in-crop fertigation impacts N 2 O emission factors (EF) in irrigated wheat (Triticum aestivum) and canola (Brassica napus) in Southern Alberta, Canada during two growing seasons (May to Oct. in 2015 and 2016). With all the N applied at crop seeding, the growing-season N 2 O EF of irrigated wheat and canola was in average 0.23 ± 0.03%. Conversely, implementing N fertigation lowered the magnitudes of N 2 O EF in each of the four crop-years, averaging 0.16 ± 0.04%. Most of the reductions in N 2 O emissions due to fertigation occurred with low and intermediate N rates (total rates of 60 and 90 kg N ha -1 ) and in the second year of the study. This second year had recurrent, early-season rainfalls following seeding (and prior to fertigation) that triggered differences in the daily and cumulative N 2 O fluxes. Within this year, fertigation on wheat consistently lowered the growing-season N 2 O EF from a high of 0.27% to only 0.11% (P < 0.001). Also, at the intermediate rate of 90 kg N ha -1 , fertigation synergistically reduced the N 2 O EF of canola by half, from 0.13% to 0.06% (P < 0.01). However, the mitigating effects of fertigation vanished with the highest N rate in the study (120 kg N ha -1 ). Even with fertigation, this highest N rate resulted in high emissions in wheat, and lesser so in canola in part due to the higher N uptake of canola. Moreover, canola often manifested narrower ratios of N 2 O emission-to-grain yield (EF yield ) than wheat. This interplay of crop species, rainfall and N management suggests that implementing fertigation with reduced N rates can proactively mitigates N 2 O.
Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
(Copyright © 2020 Elsevier B.V. All rights reserved.)
Databáze: MEDLINE
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