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To cut emissions from cattle ranching, beef up the soil, study says

Allowing native species of trees to grow in pastures can reduce livestock emissions while also providing shade for cattle. Image courtesy of Hacienda San José.

  • A pilot project funded by the World Bank in Colombia’s Vichada municipality found that land management techniques paired with the implementation of a tropical grass species increased carbon storage in the soil by more than 15%, while also avoiding the need for cyclical burning of the savanna.
  • Improving the productivity of inefficient ranching practices can boost profits for ranchers while combating growing food insecurity in Colombia, say the authors of a recent study documenting the pilot project.
  • The study comes amid relative silence at the COP27 climate summit about the role of livestock in climate change: A quarter of all global emissions come from the livestock industry, yet serious measures to reduce or improve these systems are not being discussed enough, experts say.
  • Scientists not involved with the pilot project have welcomed the findings but note that biodiversity indicators also need to be measured to compare the improved pastures to natural savanna.

Flying this November into a remote region of the Orinoquía savanna in Vichada, Colombia, environmental biologist Jacobo Arango could spot the Hacienda San José cattle ranch that his team was using as an open-air laboratory.

From the sky, he could see the farm’s greener hue of grass standing out against neighboring pastures. There, he and his team from the International Center for Tropical Agriculture in Cali were experimenting with a tropical grass species called Brachiaria humidicola. Combined with rotational grazing, they wanted to improve the region’s shallow, acidic soil while measuring how much carbon could be captured.

As the taller, denser grass worked to feed more cows above land, its meter-deep (3-foot) roots improved soil quality, also allowing some native tree species to proliferate. The soil absorbed at least 15% more carbon than the adjacent pastures, Arango found.

“Scaling the implementation of land-based carbon storage practices could significantly contribute to reducing net emissions from beef production,” Arango and colleagues wrote in a recently published study about their findings, funded by the World Bank.

The Orinoquía region covers the vast eastern grassland plains of Colombia and produces a fifth of its beef, according to the 2022 census, but the land is notoriously degraded. The aluminum-rich soil common throughout the region is toxic for most grass species. Poor-quality pasture means that cattle need 17 hectares (42 acres) each to get enough food.

The nutrient-poor soil also leads to local farmers setting more fires, as the ash works to fertilize the land — a practice that advocates of rotational grazing techniques say can be avoided altogether by letting cattle graze in smaller areas while other parts of the pasture recover.

researcher
Researchers led by Jacobo Arango found they could achieve deeper roots and greater carbon storage in the soil after six years of adopting land management techniques in combination with a tropical grass species on a Colombian ranch. Image courtesy of the International Center for Tropical Agriculture (CIAT).

Colombian President Gustavo Petro, who took office in August this year, called the use of extensive and underutilized land “inadequate,” and promised during his campaign to transform these areas into more productive silvopastoral systems — growing trees inside pastures.

Arango’s experiment took place on just one farm, but his hope is to scale the model to other cattle ranches in the 11-million-hectare (27-million-acre) Orinoquía region. With this system, pastures here could store around the twice the amount of the region’s carbon emissions from livestock over the next 20 years.

Orinoquia’s farms currently emit 15-23 kilograms of carbon dioxide per kilogram of beef produced. But at the Hacienda San José, the carbon footprint is now negative: for every kilo of beef, 17.5 kilos of CO2 are instead absorbed from the atmosphere, according to a report published by the same team.

After 20 years, Arango said, the soil may hit its maximum capacity for carbon storage and those environmental benefits would taper off.

At the COP27 climate conference in November, President Petro said in his keynote speech that “it is now the time for humanity, not markets.” But there was little discussion about the livestock industry that occupies 25% of the world’s habitable land and is responsible for the same proportion of global greenhouse gas emissions, according to a 2021 study. Atul Jain, a co-author of that study and atmospheric scientist at the University of Illinois, says more needs to be done to keep global warming within the Paris Agreement ceiling of 1.5° Celsius (2.7° Fahrenheit) above pre-industrial levels.

“It is such a huge reduction target. I doubt all these methods can help us to accomplish that goal,” Jain told Mongabay. “We really need to think about changing high carbon footprint diets, of which beef is the highest emitting, to something like chicken which has a much lower carbon footprint.”

But for Arango, reducing Colombia’s beef footprint needs to work alongside emissions reductions. “I hope the study will once again call for action in the cattle sector to reduce emissions,” he told Mongabay by phone. “Just because we are sequestering carbon in soil, it doesn’t mean we should not be worried about reducing emissions.”

Higher efficiency and less emissions

In less than seven years, productivity at the 8,000-hectare (20,000-acre) Hacienda San José has jumped under Arango and his team’s watch. The amount of pasture needed per head of cattle has dropped from 17 to 1 hectare (42 to 2.5 acres). While increased efficiency would also emit more methane, with more cattle squeezed into a smaller space, the emissions per individual animal decreases as the land is put to better use than the degraded pastures that make up most of the industry today.

“There is a lot of room to improve efficiency and at the same time reduce the environmental footprint of the system,” Arango said. “One of the problems of the current livestock systems is that they are highly inefficient.”

The hacienda where the experiment is being hosted is owned by Gabriel Jamarillo, who formerly headed the Global Fund to Fight AIDS and was a top executive at Citibank and Bank Santander.

“I’ve always looked for things that have a huge social impact,” Jamarillo told Mongabay by phone. He said he hopes to expand his farm by another 172,000 hectares (425,000 acres) over the next decade. “Colombia needs to develop its agricultural industry but for historical reasons, it never has.”

cattle
Tall, dense grass combined with rotational grazing allows cattle ranchers to keep 17 times more cattle per hectare than neighboring pastures in Vichada, Colombia. The technique also replaces the annual burning of pastureland, a practice that emits large amounts of greenhouse gasses. Image courtesy of Hacienda San José.

Expectations for increased food security were high following the 2016 peace pact that brought an end to Colombia’s decades-long and bloody civil war with the FARC guerrillas. But food security has since worsened, according to a May 2022 study using data from the Gallup World Poll. A quarter of the population now suffers from severe food insecurity, up from 8% between 2016 and 2019. Two-fifths of Colombians are impacted to some degree by food insecurity.

“Food security is extremely fragile,” Jamarillo said. “We are improving the soil for future generations while adding to the food sector today. If we leave the soil better than we found it, it’s regenerative agriculture.”

Carbon isn’t everything

Mercedes Bustamante, a leading biologist who studies the savanna ecosystem in neighboring Brazil, said further research needs to look at non-degraded savanna as a second control group so that policymakers are able to map the best use of land in the region. That way, they can designate some areas for protection and others for commercial activity. According to a 2020 global study on livestock ranching, wherever there are cattle, there is less biodiversity.

In the Cerrado savanna in Brazil’s center-west region, Bustamante said, biodiversity-rich grasslands are being aggressively converted to sprawling pastures using a close relative of the B. humidicola grass species being tested in Vichada, but with more conservative carbon storage results.

“Recovering degraded natural systems is also a carbon removal strategy,” she told Mongabay. “You can’t switch water for carbon, or biodiversity and traditional territories for carbon, so we need to understand more about what is happening in the region.”

Arango said the goal of reducing the environmental footprint of the livestock systems will have a better chance of success if farmers can profit from investing in reducing emissions and storing carbon, and even gain access to climate mitigation funding. Soil carbon absorption has an end date, he added, and farms can’t be net-carbon-negative forever.

“But the cattle sector is able to also absorb carbon from the atmosphere,” Arango said, “compared to airplane activity, for example, which can only emit.”

See related: 

Better livestock health reduces carbon emissions (commentary)

Citations:

Costa Jr., C., Villegas, D. M., Bastidas, M., Matiz-Rubio, N., Rao, I., & Arango, J. (2022). Soil carbon stocks and nitrous oxide emissions of pasture systems in Orinoquía region of Colombia: Potential for developing land-based greenhouse gas removal projects. Frontiers in Climate4. doi:10.3389/fclim.2022.916068

Arango, J., Bastidas, M., Costa Jr., C., González, R., Marin, A., Matiz-Rubio, N., … Villegas, D. (2022) Carbon footprint and mitigation scenarios for Hacienda San Jose: Identifying opportunities and challenges using a consolidated modelling framework. International Center for Tropical Agriculture (CIAT). Retrieved from: https://hdl.handle.net/10568/121105

Xu, X., Sharma, P., Shu, S., Lin, T., Ciais, P., Tubiello, F. N., … Jain, A. K. (2021). Global greenhouse gas emissions from animal-based foods are twice those of plant-based foods. Nature Food2(9), 724-732. doi:10.1038/s43016-021-00358-x

Filazzola, A., Brown, C., Dettlaff, M. A., Batbaatar, A., Grenke, J., Bao, T., … Cahill, J. F. (2020). The effects of livestock grazing on biodiversity are multi‐trophic: A meta‐analysis. Ecology Letters23(8), 1298-1309. doi:10.1111/ele.13527

Soil carbon storage and sequestration potential in the Cerrado region of Brazil. (2006). In R. Lal & C. Cerri (Eds.), Carbon Sequestration in Soils of Latin America. CRC Press. Retrieved from: https://www.taylorfrancis.com/chapters/edit/10.1201/9781482298031-23/soil-carbon-storage-sequestration-potential-cerrado-region-brazil

Banner image:  Allowing native species of trees to grow in pastures can reduce livestock emissions while also providing shade for cattle. Image courtesy of Hacienda San José.

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