When I picked up Kristin’s Ohlson’s The Soil Will Save Us, the idea that anything could reverse the effects of global climate change seemed worth investigating. Ohlson’s claim that dirt could make this happen was even more intriguing. As a gardener, I’ve long been curious about soil, which often behaved in mysterious ways. The Soil Will Save Us satisfied my curiosity on both accounts. And I welcomed the way it stands out in today’s “literature of wrongness”—leaving me feeling hopeful rather than depressed.
Chapter 1 asks, “Where did all the carbon go?” The plot of ground Ohlson is looking at here used to give up its carbon, she says, to food, whiskey, and linsey-woolsey clothing—one answer. Ohlson seems always to be looking at a specific piece of ground, and talking to the scientist, farmer, or rancher connected with it. In this way she presents the science as it unfolds with her real-life interactions, communicating her concepts through stories. (I appreciated that: soil may be complex, but it shouldn’t be dry!) Her first character, an East Indian who directs the Carbon Management and Sequestration Center at Ohio State, hosts a visitor who argued, back in 1957, that the high volume of soil carbon being released into the atmosphere was alarming. Their conversation reveals a second, more important answer to the chapter’s question: Too much soil has been plowed up and air-dried, leaving its carbon to combine with oxygen and float upward as carbon dioxide.
Next, just in case her reader knows nothing about soil, Ohlson goes back to the birth of Earth and the first appearance of the microscopic critters that make soil a living thing. I realized I didn’t have to learn the names of these underground species (there are too many), just what they do to—and for—plants. For example, these microbes (with help from other players like bugs, worms, and fungi) build aggregates in the soil, loosening it up nicely. They also make minerals available to the roots of plants. I finally understood an elusive truth: tilling, turning over, plowing, drying out, or otherwise disturbing the home of these organisms leaves the seeds you plant without some of their best allies.
For plants and the invisible life down under, it’s a mutually beneficial relationship. Microbes need the carbon sugars that plant roots provide. “Plants leak,” writes Ohlson, in her characteristically direct and energetic prose. I finally understood that principle, too. After your harvest, you’ll only starve those microorganisms if you remove the roots and leave the ground bare. You have to keep feeding this “underground herd,” even when you’re not growing food for people. Or, at the very least, cover the ground with a good layer of organic material.
Although no-till farming and cover crops are not exactly new concepts, I liked the way a better understanding of soil led me to logical and convincing arguments about their necessity. In the same way, the problems with fertilizers, pesticides, and genetically modified crop systems also became clear.
The book is not another rant against practices whose overthrow will cost us dearly—or, in this case, leave the world hungrier. It holds that less is truly more—that the expense of farm equipment, engineered seeds, and manufactured crop inputs is greater for the farmer in the long run than are the costs of a lower-tech, health care plan for soil. And the planetary benefits of cleaner water and air, not to mention food quality and diversity, are obvious.
But will the soil really save us? If so, how?
Before reading this book I was unfamiliar with the term “legacy load.” I figured the best I could do in my own life to fight climate change was minimize my carbon footprint and curb the emissions resulting from my daily habits. If I thought at all about the problem of excess carbon dioxide already in the atmosphere, it was in the context of scientists trying to create fake, carbon-eating “trees.” According to Ohlson, however, soil can actually remove some of that existing carbon load from the air, partly because so much of the Earth’s soil has become carbon-poor and lifeless. I learned that desertification isn’t new. In fact, even the Sahara and other major deserts were created by milk-it-and-move-on agriculture. People have farmed this way since they dropped the first seeds in the ground. It is only a serious problem now because of the seriously large number of humans on the planet.
It’s not just farmers who deplete and run; ranchers are guilty of the same behavior. Initially, I was disappointed that my soil enlightenment was going to include animals, because I don’t intend to have livestock, ever. (Well, maybe a few chickens.) But the stories and science about the effect animal herds have on soil were perhaps the most fascinating aspect of the book and, I see in retrospect, essential to a global picture of soil—beyond their obvious biological contributions, of course. With ranching, too, the simplest practices, like cutting the herd’s time in one spot and preventing them from spreading out too much, make a world of difference.
Unfortunately, there isn’t much money to be made off the simpler agricultural practices. Modern methods of growing food plants and animals are economically entrenched, like so many other systems of civilization. I expect that the scientific knowledge we’re gaining about how soil works will be disputed and denied by the corporations that stand to gain from the status quo. In other words, the soil will only save us if we nurture the soil. And the need for human action is always where things get iffy.
Does this lessen the importance of The Soil Will Save Us? I don’t think so. Knowledge is the best defense against propaganda. And, with regard to the basics of soil, I doubt there’s a more entertaining read. It’s a subject that can only benefit from being tied to something rather critical, like human survival. It’s a subject I was happy to see dealt with in popular language, with story-based science, in a broad and relevant context.
This book is just a beginning. As Ohlson says, “the world comprises many microclimates,” and each one will require a different approach. What cover crops might work for the Sonoran Desert? What can be learned from native practices? What techniques will the low rainfall here suggest? It’s time to stop creating dusty wastelands in every region of the world and really study our living soils. If better-informed ways of growing food also prove to take some of the excess carbon out of our atmosphere, it can only be good.