Brazilian maize yields negatively affected by climate after land clearing

Over 50% of the Brazilian Cerrado has been cleared, predominantly for agropastoral purposes. Here, we use the Weather Research and Forecasting model to run 15-year climate simulations across Brazil with six land-cover scenarios: (1) before extensive land clearing, (2) observed in 2016, (3) Cerrado replaced with single-cropped (soy) agriculture, (4) Cerrado replaced with double-cropped (soy–maize) agriculture, (5) eastern Amazon replaced with single-cropped agriculture and (6) eastern Amazon replaced with double-cropped agriculture. All land-clearing scenarios (2–6) contain significantly more growing season days with temperatures that exceed critical temperature thresholds for maize. Evaporative fraction significantly decreases across all land-clearing scenarios. Altered weather reduces maize yields between 6% and 8% compared with the before-extensive-land-clearing scenario; however, soy yields were not significantly affected. Our findings provide evidence that land clearing has degraded weather in the Brazilian Cerrado, undermining one of the main reasons for land clearing: rain-fed crop production.