Simulation of future scenarios for pastures in Brazil: strategies to minimize climate risks

• Grant number: 25/16118-8
• Support Opportunities: Scholarships in Brazil - Support Program for Fixating Young Doctors
• Start date: October 01, 2025
• End date: May 31, 2026
• Field of knowledge: Agronomical Sciences - Agronomy - Agricultural Meteorology
• Principal Investigator: Fabio Ricardo Marin
• Grantee: Verônica Gaspar Martins Leite de Melo
• Host Institution: Escola Superior de Agricultura Luiz de Queiroz (ESALQ). Universidade de São Paulo (USP). Piracicaba , SP, Brazil
• Associated research grant: 24/02021-0 - Simulation of future scenarios for pastures in Brazil: strategies for minimizing climate risks, AP.R

Abstract

The global population could reach 9.7 billion people by 2050, with a large portion of the growth occurring in developing countries. This growth, coupled with rising per capita income, will result in beef demand increases of up to 35%. Although Brazil has the world's largest commercial herd raised predominantly on tropical pastures, there are still no studies on pasture production, seasonality, and agroclimatic risk in future scenarios. This study aims to (i) simulate pasture productivity under current (1987-2017) and future (2035-2065) scenarios in the Central-West, Southeast, and states of Pará and Rondônia of Brazil; (ii) simulate production seasonality (variability in productivity between seasons) and climate risk (interannual variability in productivity within each season) of tropical pastures in these scenarios; (iii) simulate and discuss the potential of irrigation, ensilage, and deferral in minimizing seasonality and climate risk in pasture-based animal production in simulated scenarios. Marandugrass [Urochloa brizantha (Stapf) Hochst ex A. Rich. (syn. Brachiaria brizantha Stapf) cv. BRS Marandu] and Mombaçagrass [Megathyrsus maximus (Jacq.) BK Simon & SWL Jacobs (syn. Panicum maximum Jacq.) cv. BRS Mombaça] will be used due to their representativeness in Brazilian pastures. The simulations will be performed with CROPGRO - Perennial Forage Model. In the case of Mombaçagrass, where the model was not parameterized with rainfed data, it will be evaluated and parameterized using three previously conducted rainfed field experiments. After model adjustments, homogeneous agro-ecological zones (HZs) will be determined using the criteria of crop degree days, temperature seasonality, and evapotranspiration for the period 1987-2017. The HZs will be cross-referenced with the Brazilian soil map. Simulations will be performed considering a meteorological station in each HZ and the predominant soil profile within it. Two atmospheric CO2 concentration scenarios will be considered: RCP 4.5 (526 ppm) and RCP 8.5 (628 ppm). Meteorological data for the period 2035-2065 will be generated using global circulation models (GCMs) following the assumptions and protocols of the fifth phase of the Coupled Model Intercomparison Project (CMIP5). Simulations will be performed under current and future scenarios, with grazing carried out every 30 days in the most productive seasons and every 60 days in the least productive seasons. Simulations will be conducted for irrigated and non-irrigated pastures to analyze productivity, seasonality, and agroclimatic risk. Silage and deferral will be simulated in the same locations where the grazing simulations were conducted to assess the potential of these strategies for minimizing seasonality and agroclimatic risk.