This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: Varying crop rotations and keeping the soil constantly covered with vegetation help protect crops against droughts and floods, in addition to increasing productivity. This technique was tested in Rio Grande do Sul state, Brazil, by researchers from the Center for Carbon Research in Tropical Agriculture (CCARBON) at the University of São Paulo (USP).
The study compared traditional crops with areas that used "cover crops"—plants grown not for sale, but to protect and nourish the soil between harvests. While the traditional model suffered major crop yield declines due to extreme weather events, farmers who adopted crop diversification and the use of cover crops managed to achieve yields above the state average (reaching as high as 76% above), with much greater stability from year to year. On the other hand, farms that followed the traditional model—such as the continuous cultivation of one type of grain after another (for example, wheat followed by soybeans) or the use of a single plant species to cover the soil—performed much more poorly.
In these areas, the harvest was very close to the state's overall average (only 8% higher) and suffered from sharp fluctuations in yield from one year to the next (ranging from 33% to 39% higher or lower), demonstrating that the simple system is far more vulnerable to climate variations and surprises. The research was conducted over three growing seasons—between 2022 and 2025—marked by extreme droughts and floods. The results were detailed in an article published on Oct. 22 in the journal Agriculture, Ecosystems & Environment.
They were also presented by professor Mauricio Roberto Cherubin of the Luiz de Queiroz College of Agriculture of the University of São Paulo (ESALQ-USP) in a lecture given during FAPESP Week Netherlands. "The study shows that to keep the soil healthy and functional, it's essential to ensure the presence of living plants and vegetation cover throughout the year," Cherubin explained to Agência FAPESP. "When we introduce a diverse mixture of cover crops, it's like offering a varied and continuous menu to the soil.
That keeps the soil organisms active year-round, optimizing the cycling of nutrients, the biological fixation of nitrogen and the availability of phosphorus for the main crop," he added. According to the researcher, the choice of Rio Grande do Sul as an experimental site is justified by its strategic position in Brazilian agriculture and its extreme climate vulnerability. The state accounts for 8.4% of national grain production.
Soybean crops in Rio Grande do Sul cover 6.8 million hectares (16.8 million acres), representing 14.4% of the total area planted with soybeans in Brazil and equivalent to 3.4% of the global market. However, the state has suffered from recurring extreme weather events: a series of severe droughts between 2019 and 2023, historic floods during the 2023/2024 growing season (which caused estimated losses of BRL 45 billion in unharvested soybean crops alone) and the return of intense droughts during the 2024/2025 growing season. To measure the interactions between soil, management practices, productivity and weather fluctuations in Rio Grande do Sul crops under real-world production conditions, the researchers analyzed data from 13 experiments conducted by farmers on commercial farms throughout the state.
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