Farming for the future: Research demonstrates the potential of pastures to sequester carbon

Ashley Becker doing field work

Story by Ashley Becker

What gives me hope for the future? Farmers.

Farmers can shift our landscape towards agricultural systems that are regenerative and I admire those who have committed to adopting sustainable practices. As I travelled throughout Wisconsin collecting soil samples and conducting interviews at a range of grazing operations, it became evident that Wisconsin graziers should be listed among those regenerative farmers. I saw firsthand how those graziers were striving to not only preserve, but regenerate their land, without jeopardizing their own wellbeing. And our research suggests that they are doing just that.

Ashley Becker, pictured here doing field work, is a Ph.D. student in Environment and Resources at UW-Madison and working with the Grassland 2.0 team doing research on the soil health of grazing operations.

Graziers using rotational grazing to raise livestock operate within a perennial agricultural system where the animals directly consume the forage grown in pastures. This contrasts with the alternative livestock feeding strategy: growing row crops, like corn, oats and alfalfa, which are then harvested and fed to animals in confinement. Rotational grazing, which incorporates the principles of rest periods between grazing events, manure management, and sustained plant cover on the land, is a superior system to row crops when it comes to soil health.

Soil sample taken during Ashely’s field work at grazing operations

Soil health is improved when soil organic matter (SOM) is increased. SOM, which is made up of decomposing plant and animal tissues, is a critical component of healthy, productive soils. Increased SOM has many benefits for farmers directly and society as a whole. It results in better water retention and infiltration. This helps farmers adapt to droughts and flooding. It also helps to minimize runoff and erosion, benefitting the public through less nutrient pollution in our waterways. The prospect of increasing SOM on farm fields to serve as a strategy for addressing climate change has received considerable attention as well. Half of SOM is soil organic carbon, so increasing SOM, and therefore carbon, helps to reduce carbon dioxide in the atmosphere.

While sequestering carbon in the soil can be a powerful tool in mitigating climate change, more needs to be learned about how soil carbon changes in practice. Our recent research in southern and central Wisconsin sought to address this need by comparing soils collected from 33 paired rotationally grazed pasture and row crop sites. Our findings support that perennial pasture is the most promising agricultural system for improving soil health. On average, pastures had more soil organic carbon (4.7 tons/acre) than row crops across the top 6-inches of soil. This significant difference was observed despite the variability in how each farmer implemented rotational grazing.

Having more soil carbon than row crops, however, doesn’t necessarily mean that pastures are accumulating carbon. Instead, it might be that pastures are better at simply maintaining soil carbon levels while row crops are losing carbon over time. So how do we know which explanation is best?   

We observed a relationship between the amount of pasture soil organic carbon and pasture age. Generally, the older the pasture, the more soil organic carbon it had, with pastures ranging from three to 100 years old. This suggests that pastures are likely gaining at least some soil carbon over time, but the accumulation appears to be slow. If we want soil carbon to increase, these pastures and their beneficial grazing practices must be maintained long-term. In other words, pastures can’t be tilled up periodically. 

Fortunately, Wisconsin graziers in this research found grazing pastures to be beneficial beyond the environmental benefits. One grazier shared, “there’s better yield, it’s better for the animals, definitely an improvement in health [for] them, better for the soil.” That same farm found grazing to often be more profitable than their row crop acres too. This experience of multiple benefits doesn’t seem to be isolated either. Another grazier succinctly highlighted the multifunctionality of rotational grazing by describing how it achieved a “triple bottom line” through its “social impacts, economic impacts, [and] environmental impacts”.

What is most telling about this system of raising animals is the joy it seems to bring to the graziers. I heard stories about how grazing can be a family affair, small children included, or how grazing simply has made farming fun again. With those improvements to quality of life, I can see why some farmers have expressed such strong commitments like, “to me, if you had to quit grazing, it’d be time to throw in the towel and quit farming.” 

What is important about all these experiences is that it doesn’t leave anyone, or anything, out of the equation. Environmental outcomes are not prioritized over farmer livelihoods and farmer livelihoods are not prioritized over animal wellbeing. The benefits to each actor in this system is what makes it a success story.  

As I drove through the rolling hills of the Driftless region or the fall foliage lining the roads north of Madison on my journey to farms, I felt like I was doing my small part to make the world better. This feeling was not because of my own actions. Rather, it was because of all the graziers I had the pleasure of meeting who deeply cared for the land. It was their stories and actions that reminded me of all the reasons we have to be hopeful. And it was clear to me that I am privileged to share these stories. Together, we can change the future for the better, one pasture at a time. 

Ashley Becker is a Ph.D. student in Environment and Resources at the Nelson Institute of Environmental Studies at UW-Madison. Her current research is exploring how variations in managed grazing affect soil organic carbon, as well as understanding farmers’ logic and motivation in selecting those grazing practices.