Enhanced-efficiency nitrogen fertilizers reduce winter losses of nitrous oxide,but not of ammonia,from no-till soil in a subtropical agroecosystem |
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| Authors: | Ricardo Henrique Ribeiro Marcos Renan Besen Priscila Luzia Simon Cimelio Bayer Jonatas Thiago Piva |
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| Institution: | 1. Departamento de Solos e Engenharia Agrícola, Universidade Federal do Paraná, Curitiba, PR, Brazil;2. Departamento de Agronomia, Universidade Estadual de Maringá, Maringá, PR, Brazil;3. AgResearch Invermay, Mosgiel, New 4. Zealand;5. Departamento de Solos, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil;6. Departamento de Agronomia, Universidade Tecnológica Federal do Paraná, Santa Helena, PR, Brazil |
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| Abstract: | Nitrogen (N) gas losses can be reduced by using enhanced-efficiency N (EEN) fertilizers such as urease inhibitors and coating technologies. In this work, we assessed the potential of EEN fertilizers to reduce winter losses of nitrous oxide (N2O-N) and ammonia (NH3-N) from a subtropical field experiment on a clayey Inceptisol under no-till in Southern Brazil. The EEN sources used included urea containing N-(n-butyl) thiophosphoric triamide (UR+NBPT), polymer-coated urea (P-CU) and copper-and-boron-coated urea (CuB-CU) in addition to common urea (UR) and a control treatment without N fertilizer application. N2O-N and NH3-N losses were assessed by using the static chamber method and semi-open static collectors, respectively. Both N2O-N and NH3-N exhibited two large peaks with an intervening period of low soil moisture and air temperature. Although the short-term effect was limited to the first few days after application, UR + NBPT urea decreased soil N2O-N emissions by 38% relative to UR. In contrast, urease inhibitor technology had no effect on NH3-N volatilization. Both coating technologies (CuB-CU and P-CU) were ineffective in reducing N losses via N2O production or NH3 volatilization. The N2O emission factor (% N applied released as N2O) was unaffected by all N sources and amounted to only 0.48% of N applied—roughly one-half the default factor of IPCC Tier 1 (1%). Based on our findings, using NBPT-treated urea in the cold winter season in subtropical agroecosystems provides environmental benefits in the form of reduced soil N2O emissions; however, fertilizer coating technologies provide no agronomic (NH3) or environmental (N2O) advantages. |
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| Keywords: | denitrification inhibitors N-(n-butyl) thiophosphoric triamide NBPT polymer-coated urea volatilization |
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