It is estimated that in the US we are losing 1% of our topsoil every year to erosion, most of which is caused by agricultural activities. In fact, the Natural Resource Conservation Service (an agency of the US Department of Agriculture) has an equation to determine “acceptable soil loss” for every acre of farmland in the US that is not measured in pounds per acre but rather in TONS per acre. If this doesn’t sound “acceptable” to you, you’re not alone.
We are losing topsoil at a rate of 10 times the pace at which it can be replenished naturally. One rainfall on unprotected, tilled soil can wash away a millimeter of soil. While that may not sound like much, it would take over 20 years for nature to replenish that same millimeter of soil through natural processes. A few rain events a year, year after year, and you can see that we have a real problem on our hands.
DO I HAVE YOUR ATTENTION?
Modern agricultural practices have contributed to the accelerated loss of topsoil. When land is left uncovered for long periods of time, wind and water wreak havoc on the soil. Constant tillage continuously breaks down soil structure and leaves it susceptible to water erosion from major and minor rain events.
We humans – specifically farmers – need to stop treating the soil like dirt. Soil is so much more than dirt. It is made up of combination of living organisms, nutrients, and rock and other minerals that play a critical role in supporting life on Earth. We need to treat it with the care that such a complex and vital system demands.
How can we do this? There are a few common sense farming principles that can be used to reduce the prevalence of soil loss. They include, but are not limited to, the following:
- Cover Cropping
- Reduced/Minimal Tillage
- Strip Cropping
- Perennial Agriculture (grasslands)
- Crop Rotation
The common theme in soil loss prevention is keeping the soil covered with living plants. The plants on top of the soil not only help shield the soil from the damaging effects of rain and wind, but also the roots add structure to the soil and aid in preventing erosion from major rain events.
Cover crops are an integral piece of soil management that NEEDS to be practiced by all farmers. Instead of having a living plant in the form of a cash crop (corn, soybeans, etc.) active for only a few months a year, we can extend the time the soil is covered and protected by planting cover crops in between harvested crops.
In a future blog I will discuss in detail the reasons and benefits of cover crops, as I believe they serve a very important role. It’s time that we stop treating our soil like dirt and take an active approach to regenerating this all-important resource.
 D. R. Montgomery, Dirt: The Erosion of Civilizations, 2nd Ed. (University of California Press, 2012)
 S. Lang, "'Slow, Insidious' Soil Erosion Threatens Human Health and Welfare as Well as the Environment, Cornell Study Asserts," Cornell Chronicle, 20 Mar 06.