\u201cThis is the first study to factor in soil carbon stocks when calculating GHG emissions in the life cycle of waste-derived bioenergy,\u201d explains Ricardo Bordonal, a crop scientist and the lead author of a study published in Science of the Total Environment<\/em><\/a> in July. \u201cUsing modeling and life-cycle assessments, we found that the environmental benefits of GHG reduction vary depending on the amount of sugarcane waste that is removed,\u201d he adds.<\/p>\n The researchers modeled three scenarios to evaluate carbon balance: 100% waste removal, 50% removal, and 0% removal. \u201cThere is no net emissions benefit from removing sugarcane waste to generate bioelectricity\u201d Bordonal explains. \u201cBrazil already has a clean, low-carbon grid, so it\u2019s more beneficial to leave the waste on the field, allowing its carbon to be fixed in the soil,\u201d he says.<\/p>\n However, according to the study\u2014funded by FAPESP and the Sugarcane Renewable Electricity (SUCRE) project run by the United Nations Development Program\u2014removing waste for G2 ethanol production can be beneficial. \u201cBy selectively removing 50% of the sugarcane waste for cellulosic ethanol, GHG emissions are reduced, because replacing gasoline with ethanol lowers vehicles\u2019 CO2<\/sub> emissions, and this offsets the carbon that would have been sequestered into the soil,\u201d explains Bordonal. However, he warns that removing all of the residue causes a larger loss of soil carbon sequestration, which is not worth the trade-off.<\/p>\n \u201cThis research delivers a strong message to the sector: there\u2019s no zero-cost option when removing sugarcane waste for G2 ethanol or bioelectricity production,\u201d says Maur\u00edcio Cherubin, a crop scientist at the Luiz de Queiroz School of Agriculture at the University of S\u00e3o Paulo (ESALQ-USP) who is also the deputy coordinator of the Tropical Agriculture Carbon Study Center (CCarbon-USP), a FAPESP-funded Research, Innovation, and Dissemination Center (RIDC). \u201cLeaving the sugarcane waste in the field can sequester between 400 and 500 kilograms of carbon per hectare per year,\u201d he adds.<\/p>\n Gisele Rosso\u2009\/\u2009EMBRAPA <\/span>Integrated crop-livestock-forestry systems are another strategy for cutting greenhouse gas emissionsGisele Rosso\u2009\/\u2009EMBRAPA <\/span><\/p><\/div>\n Reducing emissions<\/strong> \u201cSustainable farming practices could enable Brazilian agriculture to shift from a net GHG emitter to a key player in the country\u2019s climate change efforts,\u201d says Carlos Eduardo Cerri, a crop scientist at ESALQ and head of CCarbon-USP. \u201cThese techniques replace single-crop systems with models that enhance biodiversity. They improve soil health, reduce GHG emissions, and promote carbon sequestration in soil,\u201d he explains. Officially launched in September 2023, the center, based at ESALQ in Piracicaba, involves around 40 researchers and 90 grant beneficiaries.<\/p>\n Crop scientist Guilhermo Congio sees the new carbon research center for tropical agriculture as a potential boon for the country: \u201cBeyond cutting GHG emissions, CCarbon-USP can tackle critical issues like food security, low-carbon economies, and social development,\u201d he notes. Congio works at the Noble Research Institute in the US, where he develops methods to minimize the environmental impacts of beef cattle production. \u201cOne of our projects aims to measure soil health in pastures and connect those metrics to remote sensing technology. We\u2019re also studying how ranching practices impact soil health and carbon sequestration in native and managed pastures,\u201d he explains.<\/p>\n Nature-based solutions (NBS)\u2014productive systems that mimic natural processes\u2014enhance sustainability, productivity, and provide environmental services like carbon sequestration, according to CCarbon-USP researchers in a March 2023 study published in Green and Low-Carbon Economy<\/em>. Examples of NBS include integrated systems that combine farming, livestock, and forestry on the same land (see<\/em> Pesquisa FAPESP issue n\u00b0 314<\/em><\/a>), the use of biofertilizers, and biological pest control.<\/p>\n \u201cWe now have the chance to swap an unsustainable production model with one that harnesses plants\u2019 natural capacity to capture atmospheric carbon and soil\u2019s ability to store it,\u201d says Cherubin. He adds that healthy agricultural soils can hold carbon for long periods: \u201cCarbon adds nutrients to the soil, enhancing yield.\u201d Greater plant growth, in turn, captures more CO2<\/sub>, creating richer, more productive land.<\/p>\n Conversely, degraded soil results in lower yield and a diminished capacity to store carbon, much of which escapes back into the atmosphere as CO2<\/sub>. The more degraded the soil, the more it depends on nitrogen fertilizers to stimulate plant growth. These fertilizers are derived from petrochemicals, and their production emits significant amounts of greenhouse gases. Moreover, applying nitrogen fertilizers to crops releases nitrous oxide (N2<\/sub>O), a GHG that is 300 times more potent than CO2<\/sub>.<\/p>\n Valdinei Soffiati\u2009\/\u2009EMBRAPA<\/span>A field of rattlepods, a fast-growing legume species used to fix nitrogen in the soil, rotated with cottonValdinei Soffiati\u2009\/\u2009EMBRAPA<\/span><\/p><\/div>\n Microbial biodiversity<\/strong> \u201cWe will apply well-established microbiological methods, such as gene sequencing, high-throughput gene quantification, metagenomics [the study of microbial communities in a given ecosystem], and bioinformatics,\u201d explains Fernando Dini Andreote, a crop scientist at ESALQ and CCarbon-USP. One of the goals of the initiative is to develop methods for reducing the use of nitrogen fertilizers and pesticides, which would lower GHG emissions.<\/p>\n Brazilian farmers already use a wide range of techniques to preserve biodiversity and promote soil health, such as crop rotation\u2014alternating crops on the same field\u2014and no-till farming, in which crop residue is left on the soil and seeds are sown without disturbing the soil mechanically. According to Cerri, no-till farming can absorb up to half a ton of CO2<\/sub> per hectare each year.<\/p>\n Converting degraded pastures and conventional farmland into integrated crop-livestock-forestry (ICLF) systems\u2014or crop-livestock systems (ICL) without trees\u2014can also reduce GHG emissions. \u201cSoil in integrated systems can act as a methane [CH4<\/sub>] sink, absorbing between 0.8 and 1 kilogram of methane per hectare each year. Transitioning from monoculture pastures to integrated systems has also cut nitrous oxide emissions by up to 1.63 kilograms per hectare annually,\u201d explains Wanderlei Bieluczyk, a crop scientist at the Center for Nuclear Energy in Agriculture (CENA) at USP and the lead author of a June study reporting on these findings in the Journal of Cleaner Production<\/em><\/a>. Methane, a gas 30 times more damaging than CO2<\/sub>, is produced during the digestion of cattle and is primarily released through belching.<\/p>\n Funded by the Research Center for Greenhouse Gas Innovation (RCGI) and FAPESP, the study found that converting degraded pasture to integrated systems can significantly lower enteric methane emissions from cattle, with reductions of up to 122 grams of methane per kilogram of average daily weight gain. \u201cEssentially, you produce the same amount of meat, but with about a 25% reduction in enteric methane emissions,\u201d estimates Bieluczyk. Brazil boasts the world\u2019s largest commercial cattle herd, at roughly 220 million head.<\/p>\n According to Congio, it is important that carbon balance estimates for Brazilian agriculture use standardized units for GHG fluxes, as recommended in Bieluczyk\u2019s paper. \u201cMany studies rely on GHG conversion factors recommended by the IPCC [Intergovernmental Panel on Climate Change], which are typically based on research from temperate climates and different farming systems than those used in the tropics,\u201d Congio explains.<\/p>\n One of CCarbon-USP\u2019s aims is to identify plant combinations and land-use methods that promote greater carbon retention, enhance soil health, and improve yields. Researchers are particularly focused on cover crops like brachiaria, crotalaria, millet, and sorghum, which are planted between main crop cycles.<\/p>\n \u201cAs their name suggests, farmers plant one of these crops to literally cover the soil,\u201d explains Cherubin. \u201cThese crops are critical because they help cycle nutrients, fix atmospheric nitrogen, sequester carbon, control nematodes, and shield the soil from rain impact and erosion.\u201d During the previous growing season, several farms in Mato Grosso had to replant three times because of high temperatures and the absence of crop residue covering the soil.<\/p>\n In July, the soil management and health research team at ESALQ, in collaboration with Carbon-USP, released an e-book titled Guia pr\u00e1tico de plantas de cobertura:<\/em> Esp\u00e9cies, manejo e impacto na sa\u00fade do solo<\/em><\/a> (Practical guide to cover crops: Species, management, and impact on soil health), designed to help farmers optimize their cropping schedules. \u201cWe printed 3,000 copies and handed them out to farmers during an event in Bahia,\u201d says Cherubin. He notes that agriculture is especially vulnerable to climate change. \u201cCurrently, agriculture is contributing to the problem by emitting GHGs. Our goal is to demonstrate to farmers that by adopting sustainable crop management practices, they can become part of the solution\u2014by sequestering carbon and translating that into improved yields. Ultimately, the biggest winner will be farmers themselves.\u201d<\/p>\n The story above was published with the title “Carbon as an ally<\/strong>” in issue 343 of September\/2024.<\/p>\n Projects<\/strong> Scientific articles<\/strong>![\"\"](\"https:\/\/revistapesquisa.fapesp.br\/wp-content\/uploads\/2025\/03\/RPF-carbono-agricultura-boi-2024-09-1140.jpg\")
\nThe study is part of an industry effort to improve soil management and cut GHG emissions in agriculture, which accounted for 27% of the country\u2019s 2.3 billion metric tons of carbon dioxide equivalent (CO2<\/sub>e) emissions in 2022, or 9.6 metric tons per hectare\u2014CO2<\/sub>e is a global standard that measures the combined impact of all GHGs (like methane and nitrous oxide) in CO2<\/sub> terms.<\/p>\n![\"\"](\"https:\/\/revistapesquisa.fapesp.br\/wp-content\/uploads\/2025\/03\/RPF-carbono-agricultura-flor-2024-09-1140.jpg\")
\nSoil health relies on both the soil\u2019s mineral composition and the biodiversity of its plant and microbial communities. Intensive farming systems based on single crops\u2014like grains, sugarcane, or cattle pasture\u2014deplete the soil. A research initiative at CCarbon-USP is examining how shifts in soil microbiome composition and activity could influence carbon sequestration in agricultural systems.<\/p>\n
\n1.<\/strong> Research Center for Carbon in Tropical Agriculture (CCarbon) (n\u00b0 21\/10573-4<\/a>); Grant Mechanism <\/strong>Research, Innovation, and Dissemination Centers (RIDCs); Principal Investigator<\/strong> Carlos Eduardo Pellegrino Cerri (USP); Investment<\/strong> R$26,319,364.85.
\n2.<\/strong> Effect of changing land use and sugarcane management practices on soil C, soil health, and associated ecosystem services: A summary of the evidence (n\u00ba 23\/11337-8<\/a>); Postdoctoral<\/strong> Fellowship; Supervisor<\/strong> Mauricio Roberto Cherubin (USP); Beneficiary<\/strong> Carlos Roberto Pinheiro Junior; Investment<\/strong> R$244,824.36.
\n3.<\/strong> Implications of the expansion and intensification of sugarcane cultivation on soil ecosystem services (n\u00b0 18\/09845-7<\/a>); Grant Mechanism<\/strong> Regular Research Grant; Principal Investigator<\/strong> Mauricio Cherubin (USP); Investment<\/strong> R$158,472.12.
\n4.<\/strong> Soil carbon dynamics and greenhouse gas balance: Implications of the removal of sugarcane leaves for bioenergy production (n\u00b0 17\/23978-7<\/a>); Grant Mechanism<\/strong> Regular Research Grant; Principal Investigator<\/strong> Ricardo Bordonal (CNPEM); Investment<\/strong> R$83,507.09.<\/p>\n
\nBORDONAL, R. O. et al<\/em>. Carbon savings from sugarcane straw-derived bioenergy: Insights from a life cycle perspective including soil carbon changes<\/a>. Science of the Total Environment<\/strong>. July 11, 2024.
\nDENNY, D. M. T. et al.<\/em> Carbon farming: Nature-based solutions in Brazil<\/a>. Green and Low-Carbon Economy<\/strong>. Vol. 1, no. 3, pp. 130\u20137. May 4, 2023.
\nBIELUCZYK, W. et al.<\/em> Greenhouse gas fluxes in Brazilian climate-smart agricultural and livestock systems: A systematic and critical overview<\/a>. Journal of Cleaner Production<\/strong>. Vol. 464, 142782. July 20, 2024.<\/p>\n