title: Application effects of coated urea and urease and nitrification inhibitors on ammonia and greenhouse gas emissions from a subtropical cotton field of the Mississippi delta region.
abstract: Nitrogen (N) fertilization affects both ammonia (NH3) and greenhouse gas (GHG) emissions that have implications in air quality and global warming potential. Different cropping systems practice varying N fertilizations. The aim of this study was to investigate the effects of applications of polymer-coated urea and urea treated with N process inhibitors: NBPT [N-(n-butyl)thiophosphoric triamide], urease inhibitor, and DCD [Dicyandiamide], nitrification inhibitor, on NH3 and GHG emissions from a cotton production system in the Mississippi delta region. A two-year field experiment consisting of five treatments including the Check (unfertilized), urea, polymer-coated urea (ESN), urea+NBPT, and urea+DCD was conducted over 2013 and 2014 in a Cancienne loam (Fine-silty, mixed, superactive, nonacid, hyperthermic Fluvaquentic Epiaquepts). Ammonia and GHG samples were collected using active and passive chamber methods, respectively, and characterized. The results showed that the N loss to the atmosphere following urea-N application was dominated by a significantly higher emission of N2O-N than NH3-N and the most N2O-N and NH3-N emissions were during the first 30-50 days. Among different N treatments compared to regular urea, NBPT was the most effective in reducing NH3-N volatilization (by 58-63%), whereas DCD the most significant in mitigating N2O-N emissions (by 75%). Polymer-coated urea (ESN) and NBPT also significantly reduced N2O-N losses (both by 52%) over urea. The emission factors (EFs) for urea, ESN, urea-NBPT, urea+DCD were 1.9%, 1.0%, 0.2%, 0.8% for NH3-N, and 8.3%, 3.4%, 3.9%, 1.0% for N2O-N, respectively. There were no significant effects of different N treatments on CO2-C and CH4-C fluxes. Overall both of these N stabilizers and polymer-coated urea could be used as a mitigation strategy for reducing N2O emission while urease inhibitor NBPT for reducing NH3 emission in the subtropical cotton production system of the Mississippi delta region.
authors.affiliation: College of Resources and Environment, Northwest A&F University, Yangling, Shaanxi, China; School of Plant, Environment & Soil Sciences, Louisiana State University Agricultural Center, Baton Rouge, LA 70803, USA.
authors.forename: Zhou
authors.initials: Z
authors.lastname: Tian
authors.affiliation: School of Plant, Environment & Soil Sciences, Louisiana State University Agricultural Center, Baton Rouge, LA 70803, USA. Electronic address: jjwang@agcenter.lsu.edu.
authors.forename: Jim J
authors.initials: JJ
authors.lastname: Wang
authors.affiliation: College of Resources and Environment, Northwest A&F University, Yangling, Shaanxi, China; School of Plant, Environment & Soil Sciences, Louisiana State University Agricultural Center, Baton Rouge, LA 70803, USA.
authors.forename: Shuai
authors.initials: S
authors.lastname: Liu
authors.affiliation: College of Resources and Environment, Northwest A&F University, Yangling, Shaanxi, China. Electronic address: zqzhang@nwsuaf.edu.cn.
authors.forename: Zengqiang
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: School of Plant, Environment & Soil Sciences, Louisiana State University Agricultural Center, Baton Rouge, LA 70803, USA.
authors.forename: Syam K
authors.initials: SK
authors.lastname: Dodla
authors.affiliation: School of Plant, Environment & Soil Sciences, Louisiana State University Agricultural Center, Baton Rouge, LA 70803, USA.
authors.forename: Gerald
authors.initials: G
authors.lastname: Myers
mesh_terms: D000383:Agriculture / Q000379:methods*; D000397:Air Pollution / Q000032:analysis / Q000517:prevention & control*; D000641:Ammonia / Q000032:analysis*; D005308:Fertilizers; D003368:Gossypium / Q000254:growth & development; D008922:Mississippi; D058465:Nitrification / Q000187:drug effects; D012987:Soil; D014508:Urea; D014510:Urease
chemical_list: D005308:Fertilizers; D012987:Soil; D000641:Ammonia; D014508:Urea; D014510:Urease
keywords: Ammonia; Cotton; Emission factor; Greenhouse gas emission; Nitrification inhibitor; Urease inhibitor