H.B. Brunetti a b , I.M. Fattori Junior a , T.S.S. Dias a , M.L.A. de Melo a b , P.M. Santos c , J.R.M. Pezzopane c , K.J. Boote d , F.R. Marin a b
- aUniversity of São Paulo – “Luiz de Queiroz” College of Agriculture, Piracicaba, São Paulo, Brazil
- bCenter for Carbon Research in Tropical Agriculture (CCARBON), University of São Paulo, Piracicaba, São Paulo, Brazil
- cEmbrapa Pecuária Sudeste, São Carlos, São Paulo, Brazil
- dUniversity of Florida, Gainesville, FL, USA
Highlights
- We used 10 GCMs and CROPGRO-PFM to simulate forage under climate change
- Drought in winter and spring will slightly reduce annual forage production
- Seasonality will intensify, requiring adaptive and flexible forage management
- Future systems show high seasonality but lower interannual climate variability
- Resilient systems rely on adaptation and leveraging rainy-season forage surpluses
Abstract
CONTEXT
Brazil hosts the world’s largest commercial cattle herd, primarily raised in pasture-based systems that occupy around 164 million ha. Increasing beef production while minimizing environmental impacts is essential. Although climate change is expected to significantly affect global crop yields, comprehensive assessments of its impacts on forage production in Brazil remain scarce.
Brazil hosts the world’s largest commercial cattle herd, primarily raised in pasture-based systems that occupy around 164 million ha. Increasing beef production while minimizing environmental impacts is essential. Although climate change is expected to significantly affect global crop yields, comprehensive assessments of its impacts on forage production in Brazil remain scarce.
OBJECTIVE
Evaluate (i) the effects of climate change on forage yield, seasonality, and climate risk for Marandu palisadegrass (Urochloa brizantha cv. BRS Marandu) and Mombaça guineagrass (Megathyrsus maximus cv. BRS Mombaça) by 2050, and (ii) the effectiveness of pasture deferment and forage ensiling as mitigation strategies.
METHODS
We used the process-based CROPGRO-Perennial Forage Model (CROPGRO-PFM) driven by 10 Global Circulation Models under SSP2–4.5 and SSP5–8.5 scenarios for the 2035–2065 period, compared to a baseline (1989–2019). For the deferment simulation, pastures were left ungrazed for 75 days preceding the three consecutive months with the lowest herbage accumulation rates (HAR), assuming that 50 % of the accumulated dead material remained available for intake. Ensiling was simulated for 90 days during the three months with the highest HARs, assuming 75 % dry matter recovery, which was subsequently allocated to the three months with the lowest HAR. Both management practices were applied to 30 % of the pasture area.
RESULTS AND CONCLUSIONS
Results indicate a slight decline in annual forage yield, increased drought stress during winter and spring, and intensified seasonality. Climate risk, however, is projected to decrease as the magnitude and period of drought stress and forage deficits and supply will be more predictable, facilitating feed planning. Deferment (Marandu) and ensiling (Mombaça) were effective in reducing seasonality. Ensiling also reversed projected yield declines, whereas deferment improved yield, though not enough to reverse declines. Projected drought stress may require renewed focus on drought-tolerant cultivars and strategic use of rainy-season surpluses to buffer dry-season deficits.
SIGNIFICANCE
This study provides the first robust, multi-model, process-based evaluation of climate change impacts on Brazilian forage systems, offering valuable guidance for breeders, policymakers, and producers aiming to enhance the resilience and sustainability of pasture-based livestock systems under future climate conditions.
Keywords
Climate change, Crop modeling, DSSAT, Pasture, Livestock
