Farms in southern Brazil that diversified their crops and kept their soil permanently covered with vegetation weathered a run of severe droughts and historic floods far better than neighboring conventional operations, according to research conducted by the Center for Carbon Research in Tropical Agriculture at the University of São Paulo. Over three growing seasons marked by climatic extremes, diversified systems reached yields as much as 76 percent above the state average, while farms relying on simplified rotations hovered close to the average and swung dramatically from year to year. The findings, published on October 22 in the journal Agriculture, Ecosystems & Environment, were also presented by Professor Mauricio Roberto Cherubin of the Luiz de Queiroz College of Agriculture during FAPESP Week Netherlands.
The study compared traditional cropping models with areas that used so-called cover crops, plants grown not for sale but to protect and nourish the soil between harvests. Traditional operations in the comparison typically cultivated one type of grain after another, such as wheat followed by soybeans, or relied on a single plant species to cover the soil. These simplified systems performed markedly worse: their harvests came in only about 8 percent above the state’s overall average, and their yields fluctuated sharply, ranging from 33 percent to 39 percent higher or lower from one season to the next. That volatility, the researchers argue, demonstrates how vulnerable simple systems are to climate surprises.
The research window was deliberately demanding. Between 2022 and 2025, the team followed three consecutive growing seasons across Rio Grande do Sul, a state chosen for its strategic weight in Brazilian agriculture and its acute exposure to extreme weather. The 2022/2023 and 2024/2025 seasons brought severe droughts, with rainfall up to 54 percent below normal, ranking among the driest years ever recorded in the region. The 2023/2024 season delivered the opposite extreme, receiving 40 percent more rainfall than average. Because every farm evaluated experienced the same severe conditions at the same time, the scientists could effectively isolate climate from the equation and attribute differences in harvest outcomes to the planting techniques adopted on each field.
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