November 2012

Dear Farm Aid,

The PBS documentary about the Dust Bowl was amazing – what a disaster of epic proportions and a reminder of how important the soil is to our lives! How do today’s farmers care for the soil?

Thanks,
Scott W.
Alexandria, VA

Great question, Scott! The Dust Bowl is a breathtaking reminder of the fragility of human life without healthy soil to sustain us.

Sparked by the perfect storm of short-sighted farm practices and a prolonged drought that was only marginally worse than this year’s (check out this graphic for some context), the Dust Bowl wreaked havoc on the farm population of the High Plains, where some of the world’s most fertile soils lay beneath enormous swaths of grassland. But in a matter of decades, the rich prairie topsoil that took millennia to form was lost under mechanical plows and a failure to steward the soil from harvest to harvest.

A farmer and his two sons during a dust storm in Oklahoma, 1936 [source]

In the 1930s, dust storms overtook the skies, literally sweeping more than 100 million acres of precious soil across the country. By the middle of the decade, people left the prairie in droves, no longer able to make a living off the land. It was a tragic, humbling lesson in a dark chapter of America’s history, one that points to the enduring relevance of soil stewardship.

Soil: A precious gift

We don’t think about it very often, but soil is a life-giving resource right beneath our feet. For farmers, soil holds the nutrients that plants need to thrive, a structure to keep them rooted and a diversity of microorganisms, worms and insects for a rich ecology below the surface. For livestock producers, soil supports the forage that sustains animals on pasture and the crops used for animal feed when they’re indoors. Without this rare and precious gift, our family farmers could not enjoy a life on the land. And that means we could not enjoy their good food.

Just how precious is soil? For a little perspective, take a gander at a world map or globe.

There’s a lot of water on that map — about 75 percent of it is water in fact — leaving only a quarter of the world’s surface as dry land. But, not all of that land has soil. Vast deserts and arctic lands, mountains and other landscapes with no soil mean only about 20% of land — or 10% of the entire earth’s surface — consists of soil suitable for growing crops.[1] Consider that this same land is also used for homes, buildings, commerce and other forms of development, and you see that only a small and ever-diminishing sliver of the land on earth is available for food production.

How farmers give back to their land

The soil supporting agriculture is hard to come by — the most common estimate is that it takes 500 years to build just one inch of topsoil naturally — meaning that for all intents and purposes, soil is a non-renewable resource that must be used wisely. By investing in soil health, farmers give back to the land that supports their livelihood and way of life.

While soil stewardship has been integral to agriculture for millennia, modern industrial farm production has discouraged traditional soil stewardship practices and instead promoted the use of fertilizers, tillage and pesticides to enhance crop productivity. This has boosted the per-acre output of agriculture in America, but has been less beneficial for soil health, damaging the long-term productivity of agriculture and leaving many farmers dependent on expensive inputs and more vulnerable to natural disasters.

A recent New York Times article reinforces this point:

Modern agriculture is driven by diminishing biological diversity and relentless consolidation, from the farms themselves to the processors and the distributors of the crops and livestock. But you cannot consolidate the soil. It is a complex organism, and it always responds productively to diversity… Our idea of agricultural productivity and efficiency must include the ecological benefits of healthy soil.

We couldn’t agree more! Good soil stewardship not only preserves farm productivity, it serves as critical risk management against the wiles of weather extremes like floods or drought.

Soil organic matter, for example, increases the soil’s capacity to capture water and store it for plant roots to absorb later. Soil scientists estimate that a mere 1% increase in soil organic matter (which can be achieved through sound farm management) can increase soil’s water storage capacity by 16,000 gallons per acre! That can make a huge difference during the growing season, particularly if heavy rains threaten to overwhelm seedlings and when dry conditions hit in later months.

Looking back in order to move forward

Fortunately, farmers don’t need to reinvent the wheel when it comes to good soil — tried and true methods of soil stewardship are proving to be as essential as ever.

Diverse crop rotation is one example, employed by American farmers ever since colonial times. The practice fell by the wayside with the rise of industrial agriculture, with farms growing only one or two crop varieties on a great many acres and forgoing traditional soil health measures in favor of intense amounts of fertilizers and pesticides to stay productive.

A recent study by agronomists at the U.S. Department of Agriculture, Iowa State University and the University of Minnesota shows that a four-crop rotation works every bit as well as conventional rotations of corn and soybeans, producing as much crop while bolstering soil health, and using far less fertilizer and pesticides to do it.[2] As the cost of pesticides and fertilizers skyrocket, many farmers are returning to a diversity of crops to improve soil health naturally.

Another key strategy is planting cover crops, which are generally not harvested, but still used as part of a crop rotation. The wintertime is an especially important time for cover crops, when cold temperatures, snows, winds and bare fields can be a troubling combination for soil life. Without protection, frozen soils will kill beneficial microbes, while rough weather can erode fields or compromise soil structure.

Cover crops help moderate soil temperature and moisture levels so microorganisms and worms can survive the winter months. Roots from cover crops also maintain soil structure and water infiltration levels, something that can be compromised when fields are bare, while vegetation on the surface protect the soil from wind or water erosion in the off-season.

Cover crops are also valuable for soil fertility. By planting legumes like clover or alfalfa, farmers can restore nitrogen levels in the soil, which are depleted by crop growth and harvesting. Likewise, non-legume crops like rye, oats, and buckwheat help recycle existing nutrients and prevent mineral leaching that saps the soil of its ability to sustain life.

They say those who forget history are doomed to repeat it. At the end of the day, forward-thinking practices that pull from America’s rich agricultural past bolster the land’s productivity over the long-term, reducing our reliance on resource-intensive inputs while giving back to the soil each year. So, the next time you munch on a farm-fresh carrot or enjoy a delicious grass-fed burger, consider the very humble, but very important resource that brought that food to your table — good, healthy soil. And give thanks to our nation’s family farmers, who tirelessly steward that precious resource!

Sources

1. NASA Soil Science Education. http://soil.gsfc.nasa.gov/

2. Davis AS, et. al. (2012) Increasing Cropping System Diversity Balances Productivity, Profitability and Environmental Health. PLoS ONE 7(10):http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0047149