Soil crisis is developing throughout the mid-western United States. Few realize its significance.
The state of Iowa, for example, is the richest single piece of agricultural real estate in the world.
Yet tons of Iowa's precious topsoil are being blown and washed away faster than natural soil building can replace it.
Iowa had 12 to 16 inches of marvelous topsoil when tillage began 100 years ago. But soil erosion has dwindled topsoil in many areas to 6 or 8 inches. A precious heritage is being destroyed.
"Our best land is in the Mississippi delta," say Iowa farmers. This soil loss will affect, sooner than many of you realize, vital U.S. crop production. Why? Because productivity is directly related to the depth of surface soils and sub-soils.
The earth that is eroding in Iowa and elsewhere in the American Midwest is the darker, more humus-laden soil. It is the kind of soil most able to hold water and nutrients. Some soil loss is tolerable, as long as it is little more than the amount of soil being annually regenerated by microbial activity and plant decomposition. But agricultural officials estimate Iowa loses almost 10 tons of topsoil an acre each year.
On some Iowa farms topsoil losses are several times this shocking state average.
"Without soil we're nothing," says one Iowa soil conservation official. "Many farmers really don't believe there is a finite amount of soil," he says. This official found it hard to convince farmers that their topsoil is in danger and that they must alter their methods of tillage.
Much of Iowa's erosion is subtle because it is sheet erosion. That's in contrast to more noticeable rill or gully erosion. Sheet erosion is caused by water or wind traveling across the surface of land and removing soil fairly evenly, almost like peeling a sheet of paper from a giant pad. One ton of soil an acre is only about the thickness of a sheet of heavy paper. Ten sheet thicknesses of soil may not seem like much but it is devastating year after year.
Dr. Min Ameiya, an Iowa agronomist, says farmers have been able to mask the damage caused to soils by using hybrid seeds and applying more and more chemical fertilizers to get high yields. They fail to see the day of reckoning drawing near, he warns.
The farmers see they are getting bigger crops and wonder what we are making a fuss about," says Dr. Ameiya. "It's hard to get them to look 20 years down the road and take steps to make sure they will have land to farm."
The American agricultural export boom has intensified U.S. soil erosion. As export prices rose in the 1970s, the U.S. government stopped paying farmers to keep land idle. Farmers planted fence to fence. They brought marginal lands into production and often raised two crops instead of one. Chemical fertilizers made it possible, some farmers thought, to eliminate legume rotations and cut the hard work of spreading manure. Continuous corn (maize, for our non-American readers) was planted in many areas and chemical insecticides were poured on to handle the bugs that thrive under such conditions.
When everything went to corn and soybeans in Iowa in 1973, there was an erosion explosion. Soil losses increased 22 percent in the 1970s because of such intensive farming.
Young and old-time farmers feel justified for their farming practices. Says one old-time Iowa farmer: "Today's economy is such that big machinery, labor costs and high prices all say to the . . . farmer, 'You've got to go as hard as you can, over as much land as you can, just to make ends meet.' And that doesn't lead to good land management."
But, worries Iowa State University economist John F. Timmons, "If we erode our soil away, what will the next generation have?"
"Technology is going to run out," warns William J. Brune, who heads the soil conservation service in Iowa. "When you get down to sub-soils, fertilizer isn't going to help a farmer produce more crops."
Some soil experts estimate mid-western states could experience a 30 percent reduction in corn and soybean yields within 50 years if current erosion persists. Lester R. Brown, authority on food and population, warns, "The heavy use of fertilizer made with cheap energy has masked the basic deterioration of the soil. We're only now beginning to realize that what we're doing is not sustainable in the long run." The Bible announced this same warning for these latter days more than 3,000 years ago! You can read it in Leviticus 26:14-46 and Deuteronomy 28:15-47.