A significant opportunity to mitigate the risk of climate change is literally “beneath us,” but not in the arrogant sense of our current, political tide. I’m talking about our soils. Not the ones paved over in our urban centers, but the soils under the hundreds of millions of acres of our farm land. These soils are tended by a tiny minority of Americans, but there are ways that the rest of us could help them to do something really significant with that resource.
The Historical Resource
The original soils of our vast Midwest had around 4% “organic matter” when they supported the native prairie grasses. Traditional, plow-based agriculture changed all that, and now they only have 1-2% organic matter. Soils are actually very complex, living ecosystems. If they are left undisturbed by plows and fed by growing plants, they develop a complex, three dimensional structure composed of aggregated particles and air channels. They also store massive amounts of carbon in very long-lasting forms. This sort of soil becomes very good at capturing rainfall and storing it. It also becomes highly resistant to erosion and to nutrient leaching. If we could restore our Midwestern farmland to the sort of soils it once had, we would solve the issue of the “dead zone” in the Gulf. At the same time we would increase the world’s food supply and make it more resiliant to the heat and drought expected with climate change. Re-building these soils would remove a huge amount of carbon dioxide from the atmosphere. In the process we would reduce fuel use by tractors and reduce the energy needed to make nitrogen fertilizer.
Can We Farm That Way?
We actually know how to do this, and some farms are already successfully employing the full suite of sustainable practices to make this happen (Continuous No-till, cover crops, controlled wheel traffic, variable rate fertilization, crop rotation…). Most non-farmers would imagine that this ‘answer’ is Organic farming, but its actually not. There is an overlap of the type of farming I’m advocating with Organic in terms of using winter cover crops and rotations, but the way that “Organic” builds soil carbon is at least partially dependent on importing organic matter from other sites (e.g. in the form of tons of manure or compost…). The farming system I’m advocating builds soil in a way that imitates nature by not disturbing the soil structure and by keeping growing plants on it as much of the year as possible.
Considering All the Benefits, Why Wouldn’t We Farm This Way?
The reality is that most farms only do some of these best practices or do them inconsistently (e.g. some years no-till, some years with tillage). The reason is that it takes a good 4-6 years to transition a field to a degree of restored soil quality where all the benefits start kicking-in. During that time there are risks of yield loss (e.g. in a cool, wet spring). Once the transition is complete, the farm has lower risk, but that takes a sustained investment over time.
One of the biggest barriers to making that investment is the fact that a huge proportion of our farmland is rented (see the map above). It just doesn’t make economic sense for a farmer to go through all the trouble, risk and expense of the transition for a field for which he/she could be out-bid next year. That is one place where non-farmers could help by structuring leases to reward long-term improvement of the land. There was a time when it seemed that a “carbon market” could help farmers pay for the transition with income for sequestering carbon in their soils. That seems like a dead issue in our current political climate.
This Is Not A Complaint About Farmers
I certainly don’t want to join the chorus of people who bash farmers about sustainability issues and derisively use the term, “industrial agriculture,” for what are really just family farms. Most growers who have tried to farm this way as the no-till approach has been around for 50 years now. It is actually getting somewhat easier to make the transition with modern genetics, improved no-till equipment, auto-steered tractors, seed treatments, herbicide tolerances etc, but it is still a very real challenge (particularly with the sort of low profit margins that farmers deal with). It would only be fair for those of us who benefit from the bounty of so few people’s efforts and risk, to help pay for it.
The opportunity to up-grade soils on hundreds of millions of acres is literally “beneath us.” The benefits of doing so would be huge no matter what happens with climate change. We need to find a way to help our farmers do this.
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