Losing a thousand pounds of carbon per acre per year
From the Regenerative Agriculture Podcast with Jerry Hatfield:
John: When I think about the differences between sustainable agriculture and regenerative agriculture, the approach we’ve taken in our work is that regenerative agriculture is all about helping plants get to peak photosynthesis, produce an abundance of carbohydrates, and move those carbohydrates into the soil, where you have a very functional carbon cycle working. You’re constantly accelerating plant health and constantly accelerating soil health.
What I’ve realized is that when we think about the entire soil-plant system—as an ecosystem—you have photosynthesis, which is the way you bring new energy into the ecosystem, and you have soil biology, which processes that energy into soil. And that total energy flow—voltage, if you will—is reflected in the carbon cycle, the carbon exchange.
How does the carbon cycle shift and change when growers begin managing soils and crops differently—with regenerative management, rather than with present mainstream management?
Jerry: We do a lot of work in corn-soybean systems. Over the past seventeen years, looking at the exchanges of carbon between the plant, the atmosphere, and the soil, we’ve shown that our typical corn-soybean system is losing a thousand pounds of carbon per acre per year. This is with maybe a deep rip in the fall and field cultivation in spring, and the only thing taken off the land is the grain of corn and soybeans.
And think about the average life of a producer. Farming forty years, they’ve lost 40,000 pounds of carbon—twenty tons. It’s a slow loss, but that slow loss is impacting the aggregate stability of their soils. The farmer realizes he’s losing productivity, that it’s different than it was before, but he doesn’t come to the realization that it’s the cumulative effect of what he’s been doing over his farming career.
That’s a dynamic that we need to consider when we talk about why fields become variable overtime. But on the other hand, we can change that system quickly. And I think this is the framework that we need to be talking about. When we go to a system where we add cover crops, and we reduce the tillage intensity by going to strip-till or no-till, we find that within one year we can change that negative carbon balance into a positive carbon balance. Then we can put more dividends from that plant back into the soil biology. We go from a negative to a positive carbon balance.
John: In a single year? That is amazing.
Jerry: Yes, and even more amazing is that over a two-year period we doubled the microbial biomass in the upper twelve inches of that profile. And these are not test plots. These are 160-acre fields, and they’re sampled at 150-foot grids. So there are a large number of samples coming out of those 160 acres. We were able to improve the biology very, very quickly.
And we’ve already begun to change the upper surface of that soil. The cover crop is giving us a longer period of time in which to take carbon dioxide out of the atmosphere—converting it into carbohydrates, putting it back into the soil, and feeding that soil biology.
I always tell producers that biology wants four things. It wants food, water, air, and shelter. These are the basic necessities of life that you and I want. We should start thinking about biology from that perspective. They want a food source, just like you and I like to eat every day. In a lot of our systems we were only growing a crop during the summer. There was a long period of time on either end of the growing season when we weren’t feeding the soil biology. It had to exist on what was there, and that’s pretty much a starvation diet. If we didn’t eat three months out of a year, we’d probably be fairly thin.
Cover crops utilize a lot of solar radiation. If we don’t have a crop growing, that sunlight is just going into the surface of the earth and isn’t doing anything for us.