Soil carbon stocks and emissions greenhouse gases emission in Southwestern Brazilian cattle: bases for calculating the meat "carbon footprint"

Abstract

The emission of greenhouse gases (GHGs) is nowadays an extensively debated issue. Countries with targets for reduction in emissions of these gases have developed studies to understand the processes and mitigate emission rates. The land use change and agriculture make Brazil one of the largest emitters of greenhouse gases, reaching the fifth position in world rankings. Among the main Brazilian agricultural products are beef cattle, handled mainly in extensive systems. Quantifying and monitoring of GHG emissions in agricultural systems enable assessment of the impact of this on the environment. This proposal aims to determine the "carbon footprint" or overall evaluation of the processes of GHG emissions caused by production of meat. The experiments will be conducted on the farm Agropecuária Nova Vida, in southwestern Amazonia (Rondônia). The emission factors for cattle manure (feces and urine); fertilizer and lime in the extensive system of meat production will be determinated. To determine the gross emission will be also calculated the C stocks in pastures, subtracting the total net emissions from soil. These results will result in the "carbon footprint" of the agricultural production of meat. Through mathematical modeling, data will be extrapolated to different scenarios of meat production, seeking options that present lower emissions. For this, models already used in temperate climates will be parameterized for Brazilian conditions. The result will serve as the basis for calculation of emission factors of the main greenhouse gases (CO2, N2O and CH4) in the grazing system, and indicates the possible aspects may act in mitigation of GHG emissions from livestock farming. (AU)