Improving cropping system model of DSSAT for simulating greenhouse gases emissions for cropping systems in Brazil

Abstract

Soils act as sources and sinks for greenhouse gases (GHG) such as carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O). Since both storage and emissions capacities may be large, precise quantifications are needed to obtain reliable global budgets that are necessary for land use. Agricultural activities contribute around 20% of global anthropogenic GHG emissions from soil and have been identified as one of the main GHG sources. The Cropping System Model within Decision Support System for Agrotechnology Transfer (DSSAT) has been developed over the last four decades to address complex questions including agricultural sustainable practices, climate change and environmental impacts. The decomposition of organic matter is computed on a daily basis in the DSSAT by CENTURY-based module. This project will aim to evaluate and improve DSSAT for simulating GHG emissions for cropping systems with data collected from 4 experiments conducted in Brazil. These experiments were conducted in Carambeí - PR, Campo Novo dos Parecis - MT, Costa Rica - MS, and Itiquira - MT, with treatments of monoculture and several crop rotation sequences using soybean, bean, wheat, millet, brachiaria, and maize under conventional or no-tillage practices. The fluxes of CO2, N2O, and CH4 gases were measured during 2021/2022 season in each treatment using a manual static chamber. Based on code and parameter improvements to GHG-related algorithms, we expect to document, evaluate, and improve the GHG emissions module. In addition, we will simulate long-term scenarios exploring sustainable agriculture practices to evaluate their impacts on reducing GHGs in Brazil. Forward, this study will be helpful for computing soil carbon sequestration under several management practices, as reported in the expected results of the national post-doctoral research project (FAPESP 2022/02396-8). (AU)