Greenhouse gas balance and carbon footprint in beef cattle production systems

• Grant number: 24/15942-6
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: October 01, 2024
• End date: September 30, 2026
• Field of knowledge: Agronomical Sciences - Agronomy - Soil Science
• Principal Investigator: Ricardo Andrade Reis
• Grantee: Angélica Santos Rabelo de Souza Bahia
• Host Institution: Faculdade de Ciências Agrárias e Veterinárias (FCAV). Universidade Estadual Paulista (UNESP). Campus de Jaboticabal. Jaboticabal , SP, Brazil
• Associated research grant: 22/15974-0 - Strategic grazing management and supplementation towards sustainable intensification at tropical pasture-based beef cattle production systems, AP.TEM

Abstract

The project aims to quantify greenhouse gases (GHG) methane (CH4), nitrous oxide (N2O), and carbon dioxide (CO2) and calculate the carbon footprint in beef cattle production systems. GHG emissions will be calculated as the sum of CH4 produced by enteric fermentation and manure; N2O emissions from feces and urine deposited on pasture or in feedlots, and N2O from nitrogen fertilizer applications on pasture; and fossil CO2 emitted in the production, manufacture, and transportation of animal feed and fertilizers, diesel for farm operations and electricity production. Determining changes in soil carbon stock will be done in parallel and deducted from the total emissions, to enable the calculation of net emissions. GHG emissions will be calculated using the IPCC Tier 2 methodologies (2019). In this study, local emission factors will be used, when available. This information will calculate the carbon footprint of one kg of meat produced in both systems for the same slaughter weight of 1 AU (animal unit). Measurements will be made in laboratory conditions and an experimental area at FCAV/UNESP, consisting of 24 ha of Urochloa brizantha (Hochst. ex A. Rich) Stapf cv. Marandu pastures are divided into 12 paddocks of approximately 2 ha each. The experiment will be repeated for four consecutive years. Within each year, the experiment will be divided into two stages: rearing (rainy season, from November to March, rainy-dry transition, from April to June) and finishing on pasture or in confinement (dry season, from July to September). These measurements will include the use of incubation chambers and gas chromatographic gas analysis. The pasture assessment will include the determination of forage mass and forage quality. Animal response variables include nutrient intake and digestibility, enteric CH4, N balance, performance, carcass yield, and protein and energy deposition. Environmental impacts to be assessed include N loss through volatilization of NH3, N2O, CO2, and CH4 from excreta and fertilization of N and enteric CH4. These results may assist decision-making by government agencies, especially with regard to public policies aimed at reducing GHG emissions and ensuring sustainability in meat production in Brazil.