Researchers discussed management techniques and organic production by the MST at Porto Alegre’s Climate Action Week
Responsible for about 70% of Brazil's irrigated rice production, Rio Grande do Sul is also home to some of the country's key initiatives aimed at reducing methane emissions associated with the crop. The topic was discussed this Tuesday (7/21) during the panel "Less Methane, More Future: food security and innovation in rice cultivation," part of the program for the 1st Porto Alegre Climate Action Week (POACAW 2026).
Panelists included Mara Grohs, a researcher at the Rio Grande do Sul Rice Institute (Irga); Gabriel Quintana, coordinator of the Climate Science Initiative at Imaflora; and agronomist Edivane Portela, who works with the State Program for Ecological-Based Rice Production—in partnership with the Landless Rural Workers' Movement (MST)—at the Filhos de Sepé settlement in Viamão. The discussion was moderated by journalist Maria Helena Martinho and organized by the group Uma Gota no Oceano.
In her opening remarks, Martinho highlighted that rice is an essential food for more than half the world's population and that producing it with a lower climate impact has become a strategic challenge in the face of intensifying extreme weather events.
According to data presented during the meeting, approximately 75% of Brazil's methane emissions are linked to agriculture and livestock farming. Although irrigated rice accounts for less than 2% of these emissions, it is an activity where technologies already exist to significantly reduce this impact without compromising food production.
Soil, water, and plants: how to reduce methane emissions
While presenting studies developed by Irga, Mara Grohs explained that methane emission in flooded areas is a natural process resulting from the decomposition of organic matter in oxygen-free environments. According to her, rice crops do not produce the gas themselves, but the presence of the plant facilitates its transport into the atmosphere.
“Rice crops do not produce methane; the soil does. The presence of the plant ends up facilitating this transport,” she stated.
Grohs explained that this occurs because the plant possesses structures called aerenchyma—channels that carry oxygen from the atmosphere to the roots, allowing the plant to thrive in a flooded environment. These same channels also facilitate the escape of methane produced in the soil.
Based on this understanding, Irga began studying ways to reduce emissions by targeting three production elements: soil, water, and the plant itself. One strategy involves early soil preparation after the harvest. When water is drained from the countryside, methane emissions cease immediately. Keeping the soil drained during the winter also reduces gas formation during the following growing season.
According to Grohs, this practice can reduce emissions from the next crop by about 25%, and approximately 70% of growers in Rio Grande do Sul have already adopted this management method.
Crop rotation reduces emissions and boosts productivity
Another highlighted practice was the introduction of rain-fed crops—such as soybeans, corn, and sunflowers—into areas traditionally used for irrigated rice. According to the researcher, when rice is planted again after this rotation period, the soil remains oxygenated for longer, reducing the anaerobic activity responsible for methane formation.
Studies presented by Irga indicate that this strategy has enabled a reduction in methane emissions of up to 54% and a productivity increase of around 20%. "These practices were adopted because they boost productivity and grower profitability. And, fortunately, they have also proven to be more environmentally sustainable," Grohs stated.
The researcher also highlighted the genetic improvement work carried out by the institute. According to her, the IRGA 424 RI cultivar—one of the most widely used in the state—emits approximately 50% less methane compared to other cultivars.
Grohs explained that the program's goal was never specifically to select plants with lower greenhouse gas emissions, but rather to develop more productive varieties with shorter growth cycles. Consequently, the duration of field flooding—and thus the time available for methane formation—was reduced.
"Irga selected plants to be more productive in the shortest possible time. If the cycle is shorter, the flooding period is also shorter, and consequently, methane emissions are lower," she explained.
Grohs also noted that, despite a reduction in the area dedicated to rice cultivation over recent decades, total production has increased. According to her, when she joined Irga about 12 years ago, Rio Grande do Sul had approximately 1.2 million hectares under cultivation. Today, the area ranges from 860,000 to 890,000 hectares, yet production volume is higher.
“We are producing more rice on a smaller area and reducing the amount of carbon equivalent emitted per kilogram of food produced. This is priceless; it holds true value,” he stated.
Agroecological production relies on collective organization and value addition.
While presenting the experience of the Filhos de Sepé Settlement, agronomist Edivane Portela highlighted that Latin America’s largest contiguous organic rice production hub demonstrates the feasibility of reconciling food production, social organization, and environmental conservation.
According to him, there are no specific studies yet on methane emissions in organic rice areas, but the experience developed by the MST shows that sustainability extends beyond environmental aspects.
“The MST does something—what I call a crazy thing—which is gathering farmers who exist on the margins of society and bringing them the idea that they need to claim their space and their dignity,” he stated.
Portela emphasized that the work with these families goes beyond technical assistance, requiring the strengthening of collective organization and addressing challenges related to schooling and access to knowledge. “Often, the technical aspect takes a back seat. First, we need to talk, empower people, and work on organization,” he explained.
In his view, cooperatives are fundamental to consolidating the settlements by ensuring the processing, marketing, and value-added processing of the rice produced. As Portela noted, since family farming cannot compete on scale, product differentiation becomes essential.
At the settlement, approximately 1,600 hectares of certified organic rice allow families to receive, on average, 30% above the market price. Part of the production supplies public programs, such as the National School Feeding Program (Pnae).
Climate change demands collective responses
Recalling the 2024 floods, Portela recounted that the settlement’s rice crops suffered less impact due to the gradual rise of the water, though significant losses were recorded in vegetable production. During the crisis, the cooperative helped produce over 50,000 meals distributed through community kitchens.
“Helicopters would come to pick up the meals because many regions were cut off. It’s an image I’ll never forget,” he recounted.
For him, the experience reinforced the importance of prevention and collective organization. “We need to work on prevention and involve society as a whole. It’s not enough to act only after the disaster strikes,” he argued.
In the agronomist's assessment, living in a community will become increasingly important for facing this scenario. “This need for community living will be fundamental to overcoming these challenges,” he stated.
ABC+ Plan, Climate Plan, and public policies to reduce emissions
In his remarks, Gabriel Quintana, coordinator of Imaflora’s Climate Science Initiative, noted that the debate regarding irrigated rice must be framed within the context of Brazil’s climate goals. According to him, this agenda predates the Paris Agreement itself, drawing on the ABC Plan—launched in 2010—and the ABC+ Plan, which runs from 2020 to 2030.
“The ABC+ Plan is the national policy for mitigation and adaptation in Brazilian agriculture. It demonstrates that this concern existed even before the Paris Agreement,” he stated.
He pointed out that, although irrigated rice is not yet explicitly mentioned in the program, several of the planned practices—such as no-till farming, bio-inputs, crop rotation, and integrated production systems—are directly relevant to the crop. “Discussions are already underway to incorporate irrigated rice more specifically in the next cycle,” he reported.
The researcher explained that the ABC+ Plan also guides the Climate Plan and the Brazilian targets established in the Nationally Determined Contributions (NDCs). In his view, setting targets is not enough; it is necessary to create mechanisms for financing, technical assistance, and public policies that enable the scaling up of practices already proven effective in the field.
“It is not enough to know how much a specific practice reduces emissions. We must create the conditions for it to be implemented and scaled up,” he argued.
Quintana further stated that family farming must be included in these policies and emphasized the importance of monitoring to guide future actions. “It is important to recognize those who are already implementing these practices and to create mechanisms that allow other farms to adopt them,” he added.
Rio Grande do Sul: A hub for both production and solutions
Quintana highlighted that, although irrigated rice accounts for less than 2% of Brazil's methane emissions, Rio Grande do Sul is home to approximately 70% of the cultivated area and 74% of national production, while also offering experiences that can serve as a reference for other regions.
“The challenge lies in identifying measures that reduce these emissions without compromising the production of a food staple essential for food security,” he stated.
According to him, expanding practices such as early soil preparation could reduce methane emissions by around 200,000 tons by 2035 while maintaining productivity levels.
Quintana also highlighted the evolution of emission intensity. “In the 1980s, emissions stood at about 84 kilograms of methane per ton of rice produced. In 2024, that figure is approximately 37 kilograms per ton,” he noted.
For the researcher, these results underscore the importance of continued investment in research, monitoring, and public policies capable of scaling up practices that are already well-established in the countryside.
Irga’s environmental seal expands certification and access to the carbon market
Mara Grohs presented the Irga Environmental Seal, established 16 years ago to certify producers who adopt sustainable practices. She explained that the certification—initially focused on compliance with environmental regulations—has evolved to incorporate criteria such as soil management, the use of bio-inputs, water quality, and emissions reduction. “Currently, 180 rice producers hold this certification,” she reported. The criteria evaluated include soil preparation, no-till farming, water management, the use of bio-inputs, the quality of water returned to watercourses, and the absence of residues in the grain.
“An Irga technician visits the farm, collects a water sample, and sends it to the laboratory, which then certifies the water's quality,” Grohs explained.
The researcher stated that the certification has begun to attract interest from the carbon market because it offers assurance regarding the practices adopted on the farms. “If someone wants to buy carbon credits generated on a specific farm, a reputable institution needs to certify them,” she noted.
According to her, over the past two years, Ambev and Nestlé—through the company Indigo Agricultura—have purchased carbon credits from ten producers in Rio Grande do Sul certified by Irga. The researcher added that the federal government has begun recognizing the seal for granting benefits on financing lines and cited a call for proposals from the State Secretariat of the Environment aimed at payments for environmental services.
“Rice was the first crop in the country—and the third in the world—to have a call for proposals launched to compensate producers for the environmental services they provide,” she stated.
For Grohs, these mechanisms recognize practices that already boost productivity and now generate financial returns for producers. “Producers will adopt these practices because they increase productivity. But now, there is also an opportunity to monetize this as a form of recognition for the environmental services they provide,” she assessed.
Agroecology, social organization, and climate adaptation
In his closing remarks, Portela emphasized that the experience of the settlements demonstrates the possibility of reconciling food production, environmental preservation, income generation, and collective organization.
“Without a doubt, it is possible to develop clean, healthy, appropriate, and socially just food production. The experience we are living through can be replicated and yield good results for our agriculture,” he stated.
He also expressed concern regarding the pace of climate change. “I worry a bit about the speed at which things are happening and our capacity to respond to it,” he added.
For Quintana, addressing the climate crisis must guide decisions across all sectors. “The lens of addressing the climate crisis needs to permeate decision-making in any activity, whether in rice production, livestock farming, or the energy sector,” he argued.
In his view, successful experiences must cease to be exceptions. “Let the exception be an example to be followed—an example to be universalized for any type, size, or profile of producer,” he stated.
Concluding the debate, Grohs argued that agriculture and livestock farming should be analyzed by considering both emissions and the capacity of production systems to remove carbon from the atmosphere. “When a plant is respiring, it is also sequestering carbon,” she said.
She noted that pastures and cultivated areas also play this role and concluded with a thought-provoking point regarding emissions from other human activities. “When cattle emit methane, there is pastureland being managed to sequester that carbon. But when each of us starts our car and emits CO₂, how is that sequestered? That is the question I leave for everyone to consider,” she concluded.
By Fabiana Reinholz | From Brasil de Fato | Edited by: Marcelo Ferreira | Original URL: https://mst.org.br/2026/07/22/ciencia-e-agroecologia-apontam-caminhos-para-reduzir-emissoes-de-metano-no-cultivo-de-arroz/
July 22, 2026
