Highly Erodible Land Conservation Compliance Provisions, NRCS
Core4: Conservation for Agriculture's Future
If you've ever seen a traditional farm at the beginning of planting season then you've seen the rich, dark brown/black soil that would soon be the birthplace of whatever seed was to be sown. And if you've ever had the good fortune to actually plow the field then you've seen the huge cloud of dirt trailing behind you hanging in the air. Many farmers engage in this ritual year after year and do so to ensure a smooth planting surface that's free of other vegetation. Unfortunately, this leaves the field open to accelerated wind and rain erosion. Without vegetation there is nothing to hold the soil in place and wind and rain quickly carry away topsoil. In addition to plowing, other agricultural practices that accelerate soil erosion include overgrazing of animals, planting monocultures and even harvesting the crop itself.
While it's true that erosion is a natural process and that it has shaped the land over time, loss of topsoil on the worldwide scale that we're currently experiencing will do more than shape the land; it will shape the future in terms of food production and thus our ability as a species to survive. OK, so enough doom and gloom; is it really that bad? Well, the short answer is yes. The long answer is a little more involved.
Topsoil is essential to food production. Without it retention of water is greatly diminished. Additionally, the sublayers beneath the topsoil are more compact and therefore water is more apt to run off than be absorbed. To make these exposed sublayers even marginally productive, large amounts of fertilizer need to be applied. Because these amended soils aren't as productive as fertile soils we then need to either increase production on fertile soils (which will in turn lead to more topsoil loss) or find other suitable areas for growing food. Unfortunately, the available land for growing food is a finite nonrenewable resource. That's right, we lose topsoil faster than it is naturally produced (it takes about 200 - 1000 years to produce an inch of topsoil). It's been estimated that every year the United States loses about 4,000,000 acres of cropland (about the size of Connecticut) to erosion. This amounts to about 5 billion tons of topsoil in the U.S. alone. Worldwide, the annual loss is about 26 billion tons. Sometimes the obvious solution is the most overlooked. In this case maybe we should simply try to conserve soil, and many farmers are trying to do just that. More and more, farmers have come to realize that topsoil isn't just a good thing; it's their lifeblood and they're doing something about it Every little bit helps, whether by planting rows of trees for protection from the wind or by using reduced and/or no-till planting practices for protection from water and wind.
Historically the demise of great civilizations has been a result of topsoil depletion. So the task at hand is to either learn from history or be doomed to repeat it.
See the link below: How Much is Dirt Worth? Do the exercises that are included for background and realize that the numbers used are arbitrary. Let's say you're a farmer and have a modest size farm of 1100 acres.
- How much is the soil on the farm worth? What kinds of things affect the value of the soil? Does the value depend on what crop(s) you grow? Why or why not?
- What actions could you take to stop the erosion of your soil? How much would it cost you to implement these actions? Are certain actions more feasible than others? Are the actions you take governed by the crop(s) you grow? Why or why not?
- Where does the topsoil that erodes from your farm end up? And what consequences are there for the destination site?
- Nebraska Earth System's Education Network - Soil Erosion Demonstrationshttp://nesen.unl.edu/lessons/lessonlist.asp?topic=Soils
This page has links to eighteen soil-related demonstrations on it for various grade levels; quite interesting.
- United States Department of Agriculture - Natural Resources Conservation Service: Soilshttp://soils.usda.gov/
Everything you ever wanted to know about soils is here.
- United States Geological Survey - Suspended Sedimenthttp://webserver.cr.usgs.gov/sediment/conc.frame.html
Good visual information here that compares the suspended sediment discharges for the rivers of the United States.
- Mississippi River Factshttp://www.nps.gov/miss/features/factoids/
This site has a lot of good facts about the Mississippi River including information on sediment loading.
- What Is Erosion?http://ceed.wsu.edu/watersheds/Watershed_Education/erosion.htm
This site is sponsored by the Center for Environmental Education at Washington State University.
- How Much Is Dirt Worth?http://extension.usu.edu/aitc/resources/pdf/dirt/worth10.pdf
This is an interesting classroom activity that illustrates the value of soils. The link is to a PDF file so be sure your web browser can handle it before you go there.
- Excessive Erosion on Cropland, 1997http://www.nrcs.usda.gov/technical/land/meta/m5083.html
This page is one of many from the USDA's Natural Resources Conservation Service website of maps of soil erosion. This particular page shows total excessive erosion from cropland. This is a good site for those who prefer visuals rather than text.
- Conservation Tillage Definitionshttp://www.ctic.purdue.edu/Core4/CT/Definitions.html
Sponsored by Purdue University, the Core4 program helps farmers to increase their profits while at the same time increasing both soil and water quality. This page defines some of the tillage methods available to help meet their goals.
All material (except for some code and external links) © Jeffery A. Schneider, 2003