Spatio-temporal dynamics of soil carbon stocks and nitrous oxide emissions under Sugarcane in Brazil - convergence between specific models for time and space

Abstract

Both land use change and crop management changes under sugarcane are intensively occurring on a large scale in Brazil. It is essential to estimate the impacts of those changes in greenhouse gas emissions and soil carbon stock changes, taking into account soil, climate land use and management aspects, in order to ensure the sustainability of those processes. The goal of this project is to develop research focusing on mathematical modeling and geoprocessing applied to the assessment of soil carbon stocks and soil nitrous oxide emissions under sugarcane production in Brazil. The use of modeling and geographic information systems will enable the evaluation of the environmental impact of land use changes and crop management associated with sugarcane production, contributing to the definition of public and sectoral policies aiming at sustainable sugarcane production. This environmental modeling system will allow the comparison of different practices such as no-till, minimum cultivation and conventional tillage; replacing burned harvest by mechanized unburned harvest with maintenance of different amounts of straw on the field; the application of nitrogen fertilizers, limestone and agroindustrial residues such as stillage and filter cake; and the expansion of sugarcane over pastures, annual and perennial crops and native vegetation. The main computer models capable of simulating soil carbon stocks and soil nitrous oxide emissions will be used: CENTURY, Daycent, APSIM and RothC. Furthermore, the GEFSOC (Global Environmental Facility - Soil Organic Carbon) system, integrating modeling and geoprocessing, will be used. GEFSOC will be used to spatially and temporally explicitly map soil carbon stocks under sugarcane in Brazil in two periods: recent past (2002-2012) and future scenario (2012-2022), taking into account changes in land use and agricultural practices. Environmental modeling is an emerging research area in Brazil, and will enable scientific collaboration between research groups both in the country and abroad. (AU)