A study published by npj Sustainable Agriculture, a scientific journal from the Nature publishing group, scientifically demonstrates how second-crop corn has reduced its land-use carbon footprint in Brazil. The study focuses primarily on corn, one of the world's most important agricultural commodities, and shows how technology, developed in Brazil and dedicated to tropical agriculture, opens up opportunities for more sustainable agriculture. Second-crop corn, cultivated after soybeans in the same area and agricultural year, has gained scale in recent decades, breaking the paradigm that to produce more it is necessary to expand agricultural areas. This production system reconciles the objectives of food security, greenhouse gas reduction, and environmental preservation. Conducted by researchers Danilo Francisco Trovo Garofalo, Luciane Chiodi Bachion, and Marcelo MR Moreira from the consulting firm Agroicone; Renan Novaes, Ricardo AA Pazianotto, and Marília Folegatti from Embrapa Meio Ambiente; Furthermore, Daniel Alves de Aguiar from Canopy, Rafael Cardão Augusto from Serasa Experian, and Lucas Kreutzfeld from Epagri/SC, the study refines estimates of the carbon footprint related to direct land use and land cover change (an indicator known by the acronym dLUC) and soil management associated with second-crop corn, in addition to drawing conclusions about the positive impacts on essential sectors of the economy, such as biofuels. For two years, the group of researchers, led by Agroicone, conducted a meticulous survey that mapped, for the first time using satellite imagery, the second-crop corn producing areas throughout Brazil. Additionally, the research used MapBiomas data to analyze land use and land cover in these areas over 10- and 20-year time periods (2003–2013; 2013–2023; 2003–2023), allowing for the accounting of the carbon balance associated with land use and land cover changes and the implementation of soil management practices. The mapping identified that second-crop corn occupied 17.1 million hectares in Brazil in 2023. Between 2003 and 2023, the area of second-crop corn increased by 14.4 million hectares, consolidating the double cropping system as a differentiating factor in grain production in the country. This expansion occurred mainly on land already consolidated for agriculture, which reduces the need for new conversions of native vegetation and, above all, deforestation. Combining this mapping with carbon stock data from the BRLUC2 method, emissions associated with direct land use change (dLUC) were estimated between 0.6 and 0.9 t CO₂ per hectare per year. These values are between 40% and 57% below the estimates reported by national methodologies, and between 40% and 80% lower than international references – both cases estimate a value for Brazilian corn, without differentiating between first and second crop systems. According to Agroicone researcher Danilo Garofalo, the results highlight the relevance of incorporating spatially explicit mapping of second-crop corn areas into estimates of emissions associated with land use in the country. “This new mapping will be very useful for national and international land use models, such as BRLUC and MapBiomas themselves, to refine their estimates of land use and emissions associated with Brazilian corn, portraying them more accurately,” adds Renan Novaes, analyst at Embrapa Meio Ambiente. “Besides the effects related to the reduced need for agricultural expansion, the adoption of sustainable management practices has also allowed for increased carbon storage in the soil, compared to the single-crop system, offsetting approximately 20% of the emissions generated by land-use change,” highlights Agroicone researcher Luciane Chiodi. One of the main beneficiaries of this technological model is precisely the energy and transportation sector, in which second-crop corn ethanol is consolidating itself as an alternative capable of expanding biofuel production without requiring additional opening of agricultural areas. This environmental gain is also directly reflected in the carbon intensity of the fuel produced from this raw material. The study demonstrates that the net emissions of ethanol, resulting from land-use change and soil management associated with second-crop corn, are between 2.3 and 5.3 g CO₂ MJ⁻¹ for the 20-year period, and between 0.8 and 1.5 g CO₂ MJ⁻¹ when analyzing the most recent period. These values are lower than those presented in the literature, which calculates dLUC emissions of up to 30 g CO₂ MJ⁻¹ for Brazilian corn ethanol. “These data scientifically validate the low environmental impact of second-crop corn ethanol and its strategic potential for meeting global decarbonization targets,” reinforces Garofalo. The results quantify, for the first time, the benefits of this cultivation method and open avenues for updating national and international calculation models of the carbon footprint related to direct land use and land cover change. “The updating of these indicators consequently results in a lower carbon footprint for second-crop corn ethanol compared to current calculations, increasing the attractiveness and competitiveness of this biofuel, especially in challenging sectors such as maritime and air transport,” reiterates Chiodi. “These data scientifically validate the sector's low environmental impact and its strategic potential for meeting global decarbonization targets,” concludes the researcher.
What makes the second harvest so special?
Issues related to land use and land cover change are among the most sensitive when considering the potential adoption of biofuels, such as Brazilian corn ethanol, as an alternative for sectors that are difficult to decarbonize, such as maritime and aviation transport. The scale of these sectors demands special attention to these calculations. The study concludes that the second-crop system makes two relevant contributions to a low carbon footprint for corn-based ethanol: a) low emissions related to direct land use and land cover change (dLUC), since expanding second-crop corn cultivation does not require opening new areas in Brazil; b) a greater capacity for carbon accumulation in the soil, due to the cultivation of two crops in the same area.
Logging
The growth in the area planted with corn in the second-crop system between 2003 and 2023 had another relevant effect measured by the research: a significant decrease in deforestation or the need to expand agricultural frontiers linked to this commodity. A comparison between the 2013-2023 period and the previous ten-year period shows a 73% reduction in net annual CO2 emissions from direct land-use change (dLUC) for corn.
This text was translated by machine from Brazilian Portuguese.