Impact of cover crop inputs on N2O emissions in agroecosystems

• Grant number: 24/04981-0
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: June 01, 2024
• End date: April 30, 2025
• Field of knowledge: Agronomical Sciences - Agronomy - Soil Science
• Agreement: BG E&P Brasil (Shell Group)
• Principal Investigator: Maurício Roberto Cherubin
• Grantee: Camile Bianca Padoveze
• Host Institution: Escola Superior de Agricultura Luiz de Queiroz (ESALQ). Universidade de São Paulo (USP). Piracicaba , SP, Brazil
• Company: Universidade de São Paulo (USP). Escola Politécnica (EP)
• Associated research grant: 20/15230-5 - Research Centre for Greenhouse Gas Innovation - RCG2I, AP.PCPE

Abstract

Nitrous oxide (N2O) emissions from tropical soils primarily result from nitrification due to their well-aerated nature. The rate of N2O production during ammonium oxidation depends on the diversity and structure of the AOB and AOA communities. While AOBs generally produce more N2O relative to nitrate compared to AOA and comammox, AOA may dominate emissions in soils with higher organic matter content. Moreover, AOA and AOB exhibit distinct niches based on ammonia source rather than concentration. This study aims to investigate the impact of organic nitrogen sources, focusing in cover crop residues, on N2O emissions by varying NH4+ proportions in soil incubation experiments. The experimental setup involves soil sampling from long-term nitrogen-fertilized maize fields, with subsequent incubation under controlled conditions to simulate different organic nitrogen inputs. The N2O concentrations will be quantified over time, allowing the calculation of N2O flux. The data distribution will be assessed, and mixed-effect models will be employed to analyze the relationship between N proportion derived from cover crop residue and N2O emissions. It is expected that this study can help to elucidate the mechanisms involved in the emission of N2O in agricultural soils. Brazilians. (AU)