Feed the Plant, Starve the Soil

There are lots of reminders out there that we have a long ways to go before building soil health becomes a mainstay of our food and farming system. Some reminders are subtle, while others are about as blunt as a baseball bat to the head. A reminder of the latter variety is featured in the photo below.


As you can see, emblazoned on a giant billboard is a command from on-high: "Feed The Plant, Not The Soil." I snapped the photo while driving through southwestern Iowa a few weeks ago, and I must say that when I first spied this ad on the edge of a farm town, I did a double take. The message runs counter to everything I've been hearing from farmers, soil scientists and conservationists during the past several years while reporting on the current soil health revolution.

Back in 1995, while taking me on a tour of his southeastern Minnesota farm, Duane Hager dug up a shovelful of soil from a soybean field and showed me the results of a farming system that utilized rotations, cover crops and cow manure to build biology: it was a fragrant, crumbly, worm-filled mass teeming with life.

"Basically, you're putting on fertilizers to feed your crops," Hager said of the typical strategy of applying N-P-K to boost yields. "I want my soil feeding my crops, not me feeding my crops."

Such thinking has emerged repeatedly over the years as farmers realize the shortcomings of managing soil that's addicted to a constant applications of petroleum-based fertility, a system that, by the way, is at the mercy of world energy prices. A "feed the soil" way of thinking isn't limited to small organic farmers. Larger "conventional" producers in places like Burleigh County N. Dak., have become major proponents of utilizing no-till, cover crops and mob grazing to "feed the subterranean herd."

Just this past August I spent a week in Indiana, where, as I write in the most recent Land Stewardship Letter, a million acres of cover crops are helping corn and soybean farmers not only reduce erosion but build their soil's ability to cook up its own fertility. At one field day, western Indiana farmer Dan DeSutter asked farmers how many of them raised crops but no livestock. Many hands went up. "So you say—we're all livestock farmers when it comes to soil biology," he quipped.

Such thinking is welcome news at a time when the negative environmental problems associated with fertilizer runoff are becoming increasingly evident. Minnesota's runaway fertilizer is causing problems in local waters and all the way down the Mississippi River to the Gulf of Mexico.

An over-reliance on N-P-K has been connected with the demise of soil on a worldwide basis. On Dec. 2, the University of Sheffield came out with a calculation that the world has lost a third of its arable land due to erosion or pollution during the past 40 years. Part of this soil loss is the result of outright physical abuse: intensive plowing or overgrazing, for example. But our soil is also losing its homegrown ability to resist the erosive forces of water and wind. As microbes, fungi and other aspects of the biological universe are replaced by chemical-based fertility boosters that tend to burn up organic matter, soil becomes a compacted mass with all the life of a baked brick.

"We are increasing the rate of loss and we are reducing soils to their bare mineral components," University of Sheffield plant and soil biology scientist Duncan Cameron told the Guardian newspaper. "We are creating soils that aren't fit for anything except for holding a plant up."

And what do you do with such soil? Feed the plant like it was a baby in a high chair—except eventually even a baby matures enough to learn how to feed itself.

But then, the "feed the plant, not the soil" philosophy has a long history. It was first popularized by Justus von Liebig, a 19th Century German chemist who is considered the "father of the fertilizer industry." Using research done by, among others, botanist Carl Sprengel, Liebig did his best to debunk the "myth" that soil humus determined the productivity of plants. Rather, he argued, if we simply focused on applying fertility in the form of nitrogen, phosphorus and nitrogen (otherwise known as N-P-K), we would get exactly what we wanted from plants: big yields. Under such a scenario, soil was simply a medium for holding up the plant and passing on that fertilizer to the roots of the crop.

Later in his career, von Liebig expressed some regret about the zeal with which he promoted N-P-K to the exclusion of everything else, but the reductionist cat was out of the bag. Ever since, the N-P-K trifecta has become the center of the crop production universe. Not coincidentally, von Liebig's ideas instantaneously plucked fertility out of the grasp of farmers, and made it a marketable commodity, one that has made chemical companies countless billions of dollars over the years. Once big bucks get involved, paradigms, however misguided, become more entrenched than ever.

That's why it's so encouraging to hear farmers like Dan DeSutter say things like, "Too often farmers focus on just the chemical or physical aspect—I've learned the advantages of focusing on the biological."

And it's also why it's so disappointing to run smack-dab into a billboard ballyhooing thinking that goes all the way back to von Liebig's less enlightened time. West Central, a farm services cooperative with over two dozen locations in Iowa, is using the ad to promote "SUSTAIN," something created by United Suppliers so that retailers can, according to United's website, "…provide their growers with a leading-edge toolkit of nutrient use efficiency tools and products and soil health practices to improve yield…while reducing nutrient and soil loss and benefiting natural resources."

United Suppliers hits all the right notes in its promotion of SUSTAIN by talking about the role cover cropping and conservation tillage play in building "soil health." As the Conservation Cropping Systems Initiative in Indiana has proven, input suppliers can be major allies in advancing soil-friendly farming practices.

And in a West Central online video describing SUSTAIN, a co-op official puts the "feed the plant, not the soil" phrasing in context, saying that the goal is to make it so the plant makes use of as much applied fertilizer as possible, thus keeping it from running off and polluting the environment. Those are good intentions, but the fact remains that if soil is too starved and sick to function, even the most precise applications of fertilizer will do little good—many of those nutrients will simply pass through the plant-soil ecosystem unused.

Even if we give West Central the benefit of the doubt, the fact remains it is promoting an outdated agronomic philosophy that has done much damage over the past 175 years. It's no secret that advertising campaigns usually leave out the whole story for the sake of attention-grabbing brevity. But in this case that billboard is promoting an idea—even if by accident—that is polar opposite to the direction we should be going in farming.

This comes at a time when the benefits of feeding the soil are piling up deeper and deeper. Just a few weeks ago, world leaders meeting in Paris during the 2015 U.N. Climate Change Conference hammered out a binding agreement that gives "carbon farming" a role in curbing greenhouse gases. The agreement, which was reached during parallel meetings held during the main conference, marks the first time using soil to capture carbon has become a formal part of the global response to climate change.

By the way, the U.S. did not sign the agreement, possibly because it uses the term "agroecology," according to Ben Lilliston of the Institute for Agriculture and Trade Policy. Agroecology "has social movement and political implications" U.S. officials may not be comfortable with, Lilliston told the Food and Environment Reporting Network.

Despite the U.S. government's reluctance to support carbon farming, this agreement is a major boost for the movement to feed the soil and make it a carbon consuming ecosystem. As writers like Kristin Ohlson and Courtney White have documented, soil-friendly crop and livestock farming can play a huge role in sequestering carbon and mitigating climate change. After all, carbon makes up the majority of organic matter, and farmers have proven that sustainable practices such as cover cropping and rotational grazing can increase organic matter levels significantly in just a matter of years.

Maybe those concerned about climate change can be forgiven for ignoring the positive role farming could play in trapping carbon. After all, up until relatively recently soil scientists themselves didn't think farmers could have much of an impact on organic matter levels in a typical lifetime. It was felt agrarians' relationship with the soil basically began and ended with the fertilizer applicator.

It turns out farmers can and should have a much more complex connection to the earth beneath their feet. But then, true sustainability is hard to summarize on a roadside billboard.

Brian DeVore is the editor of the Land Stewardship Letter.