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

• Grant number: 24/02021-0
• Support Opportunities: Regular Research Grants
• Duration: July 01, 2024 - June 30, 2026
• Field of knowledge: Agronomical Sciences - Agronomy - Agricultural Meteorology
• Convênio/Acordo: CNPq
• Principal Investigator: Fabio Ricardo Marin
• Grantee: Fabio Ricardo Marin
• Host Institution: Escola Superior de Agricultura Luiz de Queiroz (ESALQ). Universidade de São Paulo (USP). Piracicaba , SP, Brazil
• Associated research grant: 21/10573-4 - Center for Carbon Research in Tropical Agriculture (CCARBON), AP.CEPID

Abstract

The world population can reach 9.7 billion people by 2050 with a large portion of the growth occurring in underdeveloped countries. This growth, coupled with rising per capita income, will result in increases in demand for beef of up to 35%. Although Brazil has the largest commercial herd in the world raised predominantly on tropical pastures, there are still no studies on pasture production, seasonality, and agro-climatic risk in future scenarios. This study aims to (i) simulate pasture productivity in 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 (productivity variability between seasons) and climate risk (interannual productivity variability in each season) of tropical pastures in these scenarios; (iii) simulate and discuss the potential of irrigation, ensiling and stockpiling in minimizing the seasonality and climate risk of pasture-based animal production in the simulated scenarios. Marandu grass [Urochloa brizantha (Stapf) Hochst ex A. Rich. (syn. Brachiaria brizantha Stapf) cv. BRS Marandu] and Mombaça grass [Megathyrsus maximus (Jacq.) BK Simon & SWL Jacobs (syn. Panicum maximum Jacq.) cv. BRS Mombaça] will be used due to their representation in Brazilian pastures. The simulations will be carried out with CROPGRO - Perennial Forage Model. In the case of Mombaça grass, where the model was not parameterized with rainfed data, it will be evaluated and parameterized using three field experiments previously conducted under rainfed conditions. After adjustments to the model, homogeneous agro-ecological zones (HZ) will be determined using the criteria of degree days of a standard crop, temperature seasonality and evapotranspiration for the period 1987-2017. The HZ will be crossed with the Brazilian soil map. The simulations will be carried out considering a meteorological station in each HZ and the predominant soil profile there. 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 carried out in 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 carried out for irrigated and non-irrigated pastures to analyze productivity, seasonality, and agro-climatic risk. Ensiling and stockpiling will be simulated in the same locations where grazing simulations were carried out to evaluate the potential use of these strategies in minimizing seasonality and agro-climatic risk. (AU)