Adding cover crops to their crop rotation can help growers improve their soil health, explained David Hammer, Ph.D., professor of Soil Genesis, University of Missouri, at the recent Lake Springfield Cover Crop Field Day near Waverly, Ill.
Hammer explains that over time, soils in different areas have developed differently with significant differences between those that developed under prairies and those that developed under forests.
“On the prairie, 70 percent of the living material is below ground, in the form of root systems, and 70 percent of that root system dies every year,” he says. This is in contrast to the soils that develop under forests, where most of the organic matter decomposes above ground. Much more organic matter is added to soil under prairie than under forests.
“When growers add a cover crop, what they’re really doing is trying to imitate the conditions of the prairie, with the diversity of species, continuous vegetative cover and the accumulation of root systems and organic matter in the soil,” Hammer says. He adds that each prairie plant has a unique rooting capacity and combined they create a soil that’s not only higher in organic matter, but that has improved water holding capacity.
“When you watch it rain on a natural prairie, you notice that surface runoff just doesn’t happen like it does on cultivated ground. “
He advises that all growers commit to choosing and then managing cover crops for a specific purpose as different species can provide different benefits, such as increasing soil organic matter, decreasing compaction or increasing water infiltration.
What advice does he offer for growers just starting out on a program to improve soil quality? “In my opinion, the most important thing to start with is finding ways to stabilize the soil surface. You’re losing the battle if you don’t commit to starting there.”
Hammer offered additional suggestions for improving soil health:
- Be sure to view fields in all seasons and in all conditions, especially during a rain.
- Talk to others. Don’t overlook the potential to learn from other growers about what’s working for them on their farms.
- Keep records. This is the best way to look back and adjust plans for the upcoming year.
- Manage for long-term objectives. You can’t always see changes in the first year or two, so pick a long-term goal and stick with it.
- Trust your instincts. If something doesn’t seem right, it’s probably not.
- Take risks. Be willing to experiment with new techniques on a portion of your farm before implementing it on the full farm.
- Use nature as a template. Cover cropping is a way of imitating the natural systems present on prairies.