Wildside: Uncovering the dirt on dirt
Many years ago, Dr. Milo Harpstead, my soils professor at UW-Stevens Point, began his lecture by informing us that the thin layer of topsoil that covers the planet's land surface is the foundation of civilization. Dr. Harpstead instructed that there's a big difference between soils and dirt. Dirt is soil out of place.
Dr. David Pimental, professor of ecology at Cornell University, studies soils and agriculture around the world. Dr. Pimental said, "Soil erosion is second only to population growth as the biggest environmental problem the world faces. Yet, the problem, which is growing ever more critical, is being ignored because who gets excited about dirt?"
Pimental wrote that soil erosion nickels and dimes us to death. One rainstorm can wash away a millimeter of dirt. That amounts to about 13 tons of topsoil eroded from a hectare (2.5 acres). It would take 20 years or more to replace that loss if left to natural processes.
The U.S. is losing soil 10 times faster than the natural rate of soil formation. The economic impact of soil losses in the U.S. is about $37 billion each year. About 60% of soil that is washed away ends up in lakes, rivers, streams, estuaries and coastal zones, making waterways more prone to flooding and to contamination from soil's fertilizers and pesticides.
Stanley Trimble of University of California at Los Angeles reported on a 26-year study of the Coon Creek Watershed in southern Wisconsin near La Crosse. Improved farming practices and soil conservation measures in Wisconsin reduced soil erosion for decades and erosion rates were then six percent of what was occurring in the 1930s. That report was published in the Journal of Science in the year 2000. Since then, there's been some serious backsliding in soil and water conservation.
Federal subsidies for commodity crops, making ethanol from corn, and reduction in land in the Conservation Reserve Program have greatly expanded area in row crops. Increased prices for corn and soybeans have farmers plowing up extensive areas of grasslands and highly erodible land and growing row crops year after year instead of rotating row crops with hay and other types of perennial cover.
The result is ugly and irresponsible. Many farmers today rent their land and don't seem to be very interested in protecting the soil. A tour of the countryside today shows evidence of rills and ephemeral gullies in fields all over the place. The result is unacceptable rates of soil loss off some of the best agricultural ground in the world, filling valley bottoms with sediment and choking streams with mud.
The solutions are simple. Plant wide grassed waterways and buffer strips along streams. Plant more perennial cover crops. Don't plow steep slopes. Practice conservation tillage. Keep cattle out of the woods, streams and off steep hillsides. Don't be greedy for short-term profit. Have respect for the land and for future generations.
One of my conservation-minded farmer neighbors recommends that the USDA should do more to promote no-till practices and educate farmers about the adverse effects of soil loss. Cost-share incentives should be readily available for landowners to install grassed waterways in fields and buffer strips along streams. Conservation Reserve Program payments should be made competitive with local land rents. Incentives should be provided to landowners to reseed old CRP fields to improve habitat. Future farm subsidies should be made contingent on meeting quantitative targets for minimum soil losses. Liquid manure should be injected into the soil, not spread on the surface or applied on frozen ground.
Congress should remove subsidies for corn-based ethanol and fund accelerated research to make cellulosic ethanol production more cost-effective. Unlike corn ethanol, cellulosic ethanol can be made from a variety of inexpensive non-food perennial feedstocks such as switchgrass and wood products.
Most farmers in this region have a strong land protection ethic and we are fortunate that they do. Civilization depends on fertile soils. Ultimately, the health of people cannot be separated from the health of the land.
Please send any comments and suggestions for this column to me at