Can regenerative agriculture deliver on its promise?
Skeptics are sowing doubts about the carbon sequestration potential. The questions underscore the complexities of soil science.
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I organized a panel discussion on regenerative agriculture at VERGE last year. First the seats filled up, then the standing room got taken. Unlucky late arrivals were left in the hallway.
In hindsight, I should have known we’d need a larger room. In a food system full of trade-offs — between biodiversity and chemical inputs and yields, to name just one — regenerative approaches offer multiple wins. By avoiding tillage and growing cover crops, producers can increase the amount of carbon stored in their soils. This leads to higher yields, lower pesticide use and, in the long run, saves money — all while drawing down carbon dioxide from the atmosphere.
The potential of regenerative ag is so clear that it’s become that rarest of things: A topic on which Democrats and Republicans can agree to work together on. It also may become an important component of carbon offset markets; startups and industry collaborations are already competing to help farmers get paid for sequestering carbon in soil.
But do we know enough about soil science to be sure that regenerative ag will deliver on its promise?
To cite one example from the piece: We have data showing that regenerative practices lead to carbon accumulating just underneath the ground, but less is known about what happens below that.
As the Yale piece points out, some research suggests that carbon may be lost from deeper layers of soil. Another example: Some studies show that the deep roots of cover crops can stimulate the activity of microbes that release carbon from soils. Could it be that regenerative ag simply redistributes carbon within soils rather than drawing it down?
I spent the week talking to soil health experts about these issues and came away confident that the attention being to regenerative ag is justified. "I don’t think it’s a ‘rather than’ situation," wrote Jane Zelikova at Carbon 180, a nonprofit that advocates for carbon removal, referring to the above question in an email.
Regenerative ag moves carbon around within soil and draws it down, she pointed out. In some soils, under some regenerative regimes, the net effect could be a loss of carbon back into the atmosphere. But evidence suggests the opposite is more common.
The same is true for microbial activity. It’s possible to stimulate microbes that release carbon dioxide and increase carbon sequestration, said Cristine Morgan at the Soil Health Institute.
"It is the net effect which is important. We want carbon to cycle because soils and farms derive so many benefits from that cycling, but with regenerative ag the focus is on tightening up those cycles so there are fewer losses and the net effect is greater storage of carbon."
The big takeaway for me was a reminder of the incredible complexity of soil science. Different producers grow a wide range of crops in very different ecosystems using multiple interpretations of what it means to be regenerative. We shouldn’t be surprised that carbon does not always behave as we’d expect.To overcome current limitations of models and ensure trust in our credits, we leverage a combination of direct soil measurements and models.
These variations should not make us wary of paying farmers to store carbon in soils, added Debbie Reed, who runs the Ecosystem Services Market Consortium, a nonprofit that is building a market for soil carbon and other ecosystem services. Instead, they are a reminder that rigorous measurement of soil carbon is needed for offset purchasers to know that their investment is having an impact.
Reassuringly, that’s an issue with which sellers of agricultural offsets are already engaged. "To overcome current limitations of models and ensure trust in our credits, we leverage a combination of direct soil measurements and models, such that any discrepancies in modeled outcomes can be accounted for over time and trued up," wrote David Perry, CEO of Indigo Ag.
I’m sure there are readers who disagree or have nuance to add. As always, you can reach me at [email protected]. I’ll share your responses over the coming weeks.