When it takes 100 years to produce one inch of topsoil, it makes sense to take care of the soil's health for the short- and long-term benefits of a farm's productivity.
Eileen Kladivko, Purdue University professor of agronomy, recommends these four strategies:
- Do all you can to reduce soil disturbance. “Reduce the amount, intensity or depth of tillage," Kladivko says. You don’t necessarily have to switch to no till, according to Kladivko, but if farmers use a moldboard plow, maybe switch to something that inverts the soil a little less, or try strip till. Loose, tilled soil leads to a higher likelihood of erosion or other environmental loss.
- Keep the soil covered. This could mean cover crops, but if a farmer doesn’t want to make that jump, there are other ways to give the fields similar protection. One simple solution? Keep crop residue at the surface.
- Try to have something growing in fields as long as possible. “The main example is cover crops or having a winter crop mixed in with summer crops,” Kladivko says. “For some farmers this could be a rotation with a hay crop. Try to have live roots for as long as possible.”
- Increase crop diversity. “In a corn and soybean rotation, adding a third crop (such as) wheat increases the diversity of plant materials,” the professor says. If cover crops are planted, she also encourages using a multi-species cover crop.
Why do these things matter? “Three of the four principles are aimed at soil biology,” Kladivko explains. She says covering the soil, keeping something growing and increased diversity helps encourage soil organisms such as microbes and earthworms to do their part.
Such activity is essential in healthy, productive soils. “The soil organisms recycle nutrients, break down crop residue and help build the soil,” she says. “Some organisms, like fungi, break down residue and excrete sticky carbon compounds that sort of glue the soil together.”
Soil might not walk around like most living creatures, but it needs to be kept alive just the same.