“We’re on a course to lose all of our topsoil,” Scharf said. “It’s not what happens in one year. It’s what happens over 100 years.”
Scharf points to data from MU climatologist Pat Guinan that shows an increasing trend of daily heavy rain events—equal to or more than 3 inches—since the 1950s.
Guinan’s research looks at these rainfall events from 1895-2010. The trend shows a 9 percent increase from 1953-2010 over the previous 58-year period. Four of the top five years with the highest number of daily heavy rain events have occurred since 1980: 1982, 1993, 2008 and 2009.
These heavy rains increase erosion greatly on both no-till and tilled soil, although no-till soils fare better. Myers and Scharf fear that recent wet springs have caused some producers to revert from no-till systems to tillage in order to fix erosion-damaged fields. They note that tillage just hides the problem and takes away the gullies, but the soil is still gone.
Terracing provides increased protection from runoff damage by reducing slope lengths and the energy of water available to carry soil off of fields, Myers said. Nevertheless, heavy rains have caused widespread damage to terraces and erosion in terraced fields during the last three springs.
Vegetative cover, dead or alive, will slow some soil loss. Scharf supports no-till farming and planting of properly managed cover crops, especially cereal rye. Costs will be offset by long-term protection of the soil, he said.
Scharf said it is important to plant cereal rye in time to get good fall growth. He suggests two weeks before the ideal time to plant winter wheat. This would be around Oct. 1 in central Missouri. Seeding with an airplane also provides a good option before row crops are harvested in the fall if the soil surface is moist. With this method, seeding should wait until leaf coverage begins to decline and 20 to 25 percent sunlight is filtering through the canopy to the ground.