Sarah Brickman, Heather Darby, Lindsey Ruhl, E. Carol Adair
{"title":"Nitrous oxide emissions are driven by environmental conditions rather than nitrogen application methods in a perennial hayfield","authors":"Sarah Brickman, Heather Darby, Lindsey Ruhl, E. Carol Adair","doi":"10.1002/jeq2.20536","DOIUrl":null,"url":null,"abstract":"<p>Agricultural best management practices (BMPs) intended to solve one environmental challenge may have unintended climate impacts. For example, manure injection is often promoted for its potential to reduce runoff and nitrogen (N) loss as NH<sub>3</sub>, but the practice has been shown to increase N<sub>2</sub>O, a powerful greenhouse gas, compared to surface application. Urease inhibitor application with N fertilizer is another BMP that can enhance N retention by reducing NH<sub>3</sub> emissions, but its impact on N<sub>2</sub>O emissions is mixed. Thus, we measured N<sub>2</sub>O, CO<sub>2</sub>, soil mineral N availability, soil moisture, soil temperature, and yield in a 2-year perennial hayfield trial with four fertilization treatments (manure injection, manure broadcast, synthetic urea, and control) applied with or without a urease inhibitor in Alburgh, VT. We used linear models to examine treatment effects on daily and cumulative N<sub>2</sub>O emissions and a boosted regression tree (BRT) model to identify the most important drivers of daily N<sub>2</sub>O fluxes in our trial. While fertilization type had a significant impact on N<sub>2</sub>O fluxes (<i>p</i> < 0.05), our treatments explained an unexpectedly small amount of the variation in emissions (<i>R</i><sup>2</sup> = 0.042), and urease inhibitor had no effect. Instead, soil moisture was the most important predictor of daily N<sub>2</sub>O fluxes (39.7% relative influence in BRT model), followed by CO<sub>2</sub> fluxes, soil inorganic N, and soil temperature. Soil moisture and temperature interacted to produce the largest daily N<sub>2</sub>O fluxes when both were relatively high, suggesting that injecting manure during dry periods or during wet but cool periods could reduce its climate impacts.</p>","PeriodicalId":15732,"journal":{"name":"Journal of environmental quality","volume":"53 2","pages":"133-146"},"PeriodicalIF":2.2000,"publicationDate":"2023-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/jeq2.20536","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of environmental quality","FirstCategoryId":"93","ListUrlMain":"https://onlinelibrary.wiley.com/doi/10.1002/jeq2.20536","RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"ENVIRONMENTAL SCIENCES","Score":null,"Total":0}
引用次数: 0
Abstract
Agricultural best management practices (BMPs) intended to solve one environmental challenge may have unintended climate impacts. For example, manure injection is often promoted for its potential to reduce runoff and nitrogen (N) loss as NH3, but the practice has been shown to increase N2O, a powerful greenhouse gas, compared to surface application. Urease inhibitor application with N fertilizer is another BMP that can enhance N retention by reducing NH3 emissions, but its impact on N2O emissions is mixed. Thus, we measured N2O, CO2, soil mineral N availability, soil moisture, soil temperature, and yield in a 2-year perennial hayfield trial with four fertilization treatments (manure injection, manure broadcast, synthetic urea, and control) applied with or without a urease inhibitor in Alburgh, VT. We used linear models to examine treatment effects on daily and cumulative N2O emissions and a boosted regression tree (BRT) model to identify the most important drivers of daily N2O fluxes in our trial. While fertilization type had a significant impact on N2O fluxes (p < 0.05), our treatments explained an unexpectedly small amount of the variation in emissions (R2 = 0.042), and urease inhibitor had no effect. Instead, soil moisture was the most important predictor of daily N2O fluxes (39.7% relative influence in BRT model), followed by CO2 fluxes, soil inorganic N, and soil temperature. Soil moisture and temperature interacted to produce the largest daily N2O fluxes when both were relatively high, suggesting that injecting manure during dry periods or during wet but cool periods could reduce its climate impacts.
期刊介绍:
Articles in JEQ cover various aspects of anthropogenic impacts on the environment, including agricultural, terrestrial, atmospheric, and aquatic systems, with emphasis on the understanding of underlying processes. To be acceptable for consideration in JEQ, a manuscript must make a significant contribution to the advancement of knowledge or toward a better understanding of existing concepts. The study should define principles of broad applicability, be related to problems over a sizable geographic area, or be of potential interest to a representative number of scientists. Emphasis is given to the understanding of underlying processes rather than to monitoring.
Contributions are accepted from all disciplines for consideration by the editorial board. Manuscripts may be volunteered, invited, or coordinated as a special section or symposium.