June 12, 2018

Soil v Dirt: A National Public Health and Policy Issue

Lacey Gaechter

Lacey Gaechter

CLF-Lerner Fellow

Johns Hopkins Center for a Livable Future

This post is the second in a series—Connecting Agriculture Policy to Your Health—by CLF-Lerner Fellow Lacey Gaechter.

In college, I rocked some Girls Love Dirt mountain biking socks, and the environmental club I founded was called Dirt First, a Simpsons reference for those of you who are fans. Let there be no mistake: this woman still loves dirt, but for growing food, dirt is not our best option. For that, we really want soil.

Unfortunately, the federal program that helps farmers turn dirt into soil could be on the chopping block, which makes this a great time to talk about how awesome soil is.

Soil v Dirt

Let’s start with the difference between dirt and soil. Dirt – often called “unhealthy soil” – is finely ground rock and thus simply a collection of lifeless minerals. Soil – often called “healthy soil” – on the other hand is dirt, plus decomposing stuff, plus microorganisms like bacteria, plus invertebrates like worms.

The decomposing stuff, microorganisms and invertebrates in soil offer two major benefits over dirt when it comes to growing food: soil produces its own nutrients and holds water. That means crops in soil require less outside fertilizer and less irrigation than crops grown in dirt. Yeah, soil’s the best.

The Problems

Farming in fertile soil without replacing its decomposing stuff, microorganisms and invertebrates will eventually turn that soil into dirt. That’s exactly what we’ve been doing in most of the United States, especially since the Green Revolution of the mid-twentieth century.

Instead of relying on nutrients from soil, we now supplement dirt with outside fertilizer, which allows us to continue growing crops. But remember that dirt is not great at retaining stuff. So when we add fertilizer to dirt, a lot of it ends up leaching into surface waters and ultimately the ocean. If we want to keep growing crops, we have to then add even more fertilizer.

Similarly, dirt does not hold much water compared to soil, and we must heavily irrigate crops grown in dirt in arid regions. Less than 1 in 10 US farmed acres is irrigated, yet agriculture consumes about 80 percent of our fresh water. Dirt is thirsty!

There are several public health problems with our approach of continuously adding more outside fertilizer and water to dirt:

  1. All that leached fertilizer is causing massive die-offs of ocean life.
  2. We get/ make fertilizers by mining and burning fossil fuels, both activities that we simply can’t do forever.
  3. We use manure from industrial animal farms as crop fertilizer. This manure is where foodborne illness outbreaks like Listeria and E.coli often come from.
  4. Agricultural workers and people who live near farms where excessive manure is required to fertilize dirt often suffer from the resulting odors, dramatically decreased property values, respiratory distress, exposure to harmful bacteria and polluted drinking water that can cause multiple health conditions, including cancer, birth defects and a blood disorder known as “blue baby syndrome.”
  5. During droughts, crop loss is dramatic in dirt, often leading to increased food prices in addition to putting farmers out of business.
  6. The use of the majority of fresh water for agriculture increases the price of drinking water, sometimes with dire consequences.

Solutions

Now that the problems with growing our food in dirt instead of soil are clear, what are potential solutions?

One of my favorite things about the USDA organic program is that organic farmers are required to build healthy soils to be certified each year. It’s true! Organic is about more than avoiding pesticides. But organic farms constitute less than 1 percent of US cropland.

Fortunately there are lots of “conventional” farmers who are committed to taking excellent care of their lands and our shared resources. Many even became farmers specifically to become stewards.

Since 2009, the best resource all famers, including organic farmers, have had to help them preserve or rebuild their soils has been the federal Conservation Stewardship Program (CSP). Through the CSP, farmers apply each year for funding to help them offset costs of soil-conserving and soil-rebuilding measures such as crop rotation and cover-cropping. In crop rotation, farmers plant a nitrogen-using crop, like corn, in a field one year and a nitrogen fixing crop, like soybeans, the next. The soybeans take nitrogen out of the atmosphere and put it back in the soil, increasing fertility without the use of synthetic fertilizers. Pretty cool, eh? When using cover crops, farmers harvest a profitable crop, like corn, then let their field “rest” with a cover crop like a native grass. The native grass keeps soil from blowing away, helps fend off weeds without the use of pesticides, preserves moisture, and breaks up the dirt so that microorganisms can colonize it once again. In other words, cover crops rebuild soils.

Crop rotation and cover-cropping can reduce short-term farm income since they both involve planting fields with less profitable or unprofitable crops in between plantings of profitable ones. For farmers new to these soil-conserving measures, there are also up-front costs with the changes to their planting system. The CSP helps farmers by sharing these costs and providing payment for some of the resulting environmental benefits of soil conservation and rebuilding measures.

If you’re thinking that this win-win-win situation that benefits farmers, the environment and humanity at large sounds too good to be true, you’re partly right. The CSP is so popular that only 25 percent of applicants get to participate each year, but there are still an impressive 70 million acres enrolled in CSP (for comparison, organic farms occupy about 5 million acres total)!

Farmers enrolled in CSP are protecting our remaining soils and turning dirt back into soil, and everyone benefits when we protect our soil! Those 70 million acres of CSP farmland require fewer outside fertilizers and less water than other conventionally farmed land. Because of CSP

  1. There is less leached fertilizer, which means we get the benefits of healthier downstream communities and healthier oceans.
  2. We don’t have to mine or burn fossil fuels as much, reducing environmental impacts and our dependence on non-renewable resources.
  3. We apply less manure to farmland and reduce our risk of contracting foodborne illnesses.
  4. Rural communities enjoy better health and quality of life.
  5. Farmers benefit from reduced crop losses and better yields during droughts.
  6. There is decreased demand on crucial drinking water supplies.
  7. Some of the carbon dioxide in the atmosphere gets sucked up by healthy soil, helping to mitigate global warming. Bonus!

To reiterate, soil is awesome, which makes the CSP awesome!

Let’s Preserve Soil Preservation!

Every five years, Congress votes whether to keep, eliminate or change the CSP as part of the larger “Farm Bill.” Negotiations for the 2018 Farm Bill are underway, and the first draft proposed in the House of Representatives would have eliminated the CSP! This version of the bill was voted down, and we are now waiting to see what the Senate proposes.

If you, like me, love soil even more than dirt, let’s make sure we keep all the benefits that CSP has to offer our environment and our health. Stay tuned right here on the Center for a Livable Future blog for updates on the Farm Bill debate continuing in Congress.

For an overview of the Conservation Stewardship Program, click here.

Image: https://www.ecolandscaping.org/01/edible-landscaping/get-the-dirt-grow-food-and-soil-with-a-food-forest/

One Comment

  1. Posted by Sue A

    Yes!– practicing regenerative agriculture is crucial in turning around climate change. Worthy of further examination, too: organic farms ideally treat their workers in an equal fashion. But some are falling short of this ideal. Also, learning the history of the USDA’s racist practices and their role in Jim Crow behavior toward Black farmers, as well as their role in the tragic loss of land and involuntary migration to the cities, hugely affecting poorer farmers, majority Black. These things are important to remember. Coming out of all this, urban food farming is a most fascinating and challenging thing! How are we going to promote, regenerate, heal, right where we are? Thanks for your blogs!! –an urban gardener

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