Assessing the effects of integrated crop-livestock systems and associated management practices on soil carbon cycling process using the Agro-IBIS model

Abstract

The adoption of crop-livestock integration systems has been used in Brazil as a strategy to achieve a more sustainable and productive agriculture, with a perspective of its implementation in areas of monoculture and extensive grazing, many of which under degradation. The integrated systems present organic compounds inputs with quantities and composition different from the traditional systems, as well as water and heat fluxes, what leads to marked changes in the magnitude of carbon (C) cycling process. In this regard, there is a lack of information about the magnitude of C cycling in integrated systems on an agroecosystem scale, especially regarding the quantitative importance of greenhouse gas emissions and changes in the organic matter stocks over the time. Therefore, the present proposal has the objective of evaluating the effects of crop-livestock integration systems and management practices on the C cycling process in the soil using the Agro-IBIS biophysical model. Given that the model has never been used before for integrated agricultural systems in Brazil, the project will consist of parameterizing and evaluating the model for this purpose. The Agro-IBIS model is currently being parameterized for soybean crop and brachiaria. This model version and associated parameters will be used as a starting point for this analysis. Meteorological and soil data, as well as land use change history will be gathered. Measured data of soil C and N, soil water content and crop yield components will be formatted and compared with model simulation outputs. After model evaluation, long-term simulations (1980-2013) will be run to assess the impact of management practises on soil C components. The parameterization and validation of Agro-IBIS for crop-livestock integration systems represent an important advance for science and Brazilian agriculture. (AU)