Cover Crops Boost Soil Health
The 2015 Commodity Classic kicked off with a session dedicated to cover crops. Farmers from Nebraska, Iowa, and Pennsylvania discussed how cover crop use can boost performance and resilience of cash crop systems.
Boost soil health
Adding cover crops to your crop rotation can increase soil biology and organic matter. “We started using cover crops to keep the soil biological activity alive after wheat,” says Keith Berns, who has used cover crops on his farm in Bladen, Nebraska, for seven years.
Berns believes that diverse cover crop mixes are a key part of building soil organic matter and biology. “If soil health is the goal, crop diversity cannot be ignored,” he says. “Plants were created to grow in diverse ecosystems, and this creates a balanced diet for soil biology.”
For Steve Groff, a founding partner of Cover Crop Solutions and farmer in Pennsylvania, cover crops are a long-term solution for soil health. From 1985 to now, Groff has been able to increase organic matter from 2% to 4.2% through cover crop use and no-till.
Groff is also interested in the ability of cover crops to scavenge available nutrients, store them over the fall and winter, and release them for the next growing season.
“Cover crops benefit the bottom line by keeping nutrients where you want them,” he says. In his research, he analyzes the uptake of nutrients by cover crops, particularly to see if this dollar amount can compensate for the cost of planting cover crops.
“If you start to assign values to the amount of nutrients the cover crops take up, it starts to be valuable,” says Groff. In one study, the amount of nitrogen and sulfur that were captured, pulled up, and made available to the cash crop added up to $60 an acre.
The ability of cover crops to tie up nutrients is also important when cash crops aren’t able to use nutrients that have already been applied. After a midseason hailstorm this summer, Berns planted a cover crop to capture nitrogen so it wouldn’t leach away.
Groff had a similar situation where he planted tillage radish into a prevented-plant field to help capture nitrogen. The following season he only needed to apply 50 pounds of N to achieve 230-bushel corn.
Manage increased rainfall
Ray Gaesser, the chairman of the American Soybean Association and a southwest Iowa farmer, started using cover crops about five years ago.
“Our defining moment was in 2010 when we had 4 inches of rain in one hour,” he says. “Our current practices, including no-till, weren’t built to handle that kind of event. That was a wake-up call to try something new.”
Gaesser now experiments with different cover crops, including legumes, radishes, turnips, and cereal rye, as well as different seeding methods to see what works best on his farm.
He has found that ground application results in a more uniform stand, at a lower price, but it is more time-consuming than an aerial application. Airplanes fly on cover crop seed quickly, but a timely rain is important for emergence.
Timing is a critical component of cover crop seeding. “If you get a cover crop planted early enough, the roots can drive down and bring up nitrogen for the cash crop,” explains Groff. “For example, October planted rye doesn’t have the ability to reach down and pull up nutrients. That’s why it’s so important to get cover crops planted in a timely manner.”
Interseeding, planting cover crops into standing corn, is one possible solution. In Groff’s research, he has found that interseeding doesn’t affect yield of the cash crop nor does it interfere with harvest. Costs to apply can also be minimized if the cover crop is seeded at the same time as sidedressing.
There are multiple solutions for interseeding, including high-clearance sprayers, Rowbots, and implements like the Interseeder or farmer-built devices. Dawn Equipment is also working on an interseeder prototype that can sidedress nitrogen and plant cover crops. The individual row units can be purchased separately and fit on existing toolbars.