To keep acreage fertile, “we need something growing in our soils year-round instead of only using it three to four months a year,” Robert Zupancic advised attendees at the seventh annual Food and Growers Association of Laughery Valley and Environs conference Feb. 9 in Batesville.
The Morgantown farmer and Natural Resources Conservation Service employee pointed out cover crops are known for erosion protection, “but they can do a lot more than that.”
These nutrient-rich crops can improve water quality, put organic matter back in the soil, break disease and insect cycles and control weeds.
He demonstrated an experiment that shows the value of these crops. A clod of conventionally tilled soil was placed in one jar and a dried-out clump that was not tilled for 20 years and had six years of cover crops over it was put in the second jar. When water was added, the first soil dissolved, but the second clod stayed together, absorbing the water. Zupancic reported a farmer found the improved soil could retain 8 inches of water, a vast improvement over the initial 2.
An annual ryegrass cover crop is recommended for producers trying to build a system of roots that can serve as underground canals for water to reach plants. On the DeSutter Farm in Fountain County, it took three to four years for roots to grow to 51 inches. Even more amazing: In August, Zupancic measured corn roots that extended 70 inches into the ground. “How much more is that drought resistant” than the typical 12 inches of roots?
Tim Schwipps, a Milan High School and Purdue University graduate who also works for NRCS, said farmers need to think of cover crops “as a prescription for what you want to accomplish. You don’t want to grow the same thing over and over again. If you want to attract beneficial insects, look at something that flowers at a certain time.”
He advised, “Think about the carbon-to-nitrogen ratio.” The ratio needed for balanced soil is 24:1. The cover crop rye straw (82:1) is slow to break down and suppresses weeds. “If you kill it early, the ratio changes to 26:1,” near the perfect ratio. The sought after nitrogen accumulation is highly dependent upon the soil’s previous fertility, type of crop, its planting date and termination and weather.
He explained, “Cover crops scavenge the nutrients left and hold them for the next crop.”
The best way to seed a cover crop is with a drill or planter, according to Zupancic. “Seed to soil contact is critical.” He added, “To drill it, the crop has got to be gone.”
Last September, when it rained the whole month, aerial and broadcast seeding both worked well, he said.
The presenter uses a screwdriver to plant cover crop seeds “like the Indians did. My kids say, ‘You’re nuts.’”
Schwipps reminded that after seeding, compost should be placed on top.
Different techniques allow cover crops to die at the right time. Crimping sometimes is used. Frost will kill some, “but 5 to 10 percent figure out a way to live through the winter,” Zupancic noted. Using herbicide is an easy method. Detailing another cover crop, he reported, “We grazed livestock on these and it saved a month of using hay (for feed).”
The timing of mowing is critical to kill some cover crops, according to Schwipps. “Mowing won’t kill crimson clover.”
He recommended, “Do your research on annual ryegrass. That is one that needs special attention” on how to make it vanish.
A few attendees posed questions. Patty Reding, Greensburg, said, “We are finding in some of the larger acreage, we’re getting into problems with superweeds, especially in organic production.” Schwipps admitted, “Herbicide resistance is huge. We’ve used Roundup to death. Cereal rye helps suppress” weeds.
George Schewe, Dillsboro, reported two years ago the family tried buckwheat as a cover crop. The dad broadcast seeded one field, but son Andy used a tiller to work seeds in and the crop grew better there. “How do I get it into the soil without disturbing it? What do I do as a small producer to work this into my soil? I can’t afford a seeder.” Zupancic suggested, “If you have to till, go as shallow as you can.” He added, “If you want to go to supersoil health levels, you’ve got to go to no-till.” Manure should be added to the soil. “If you don’t have animals, get some from another farmer. That’s how you get to the top of the pinnacle.”
Zupancic challenged cover crop skeptics to “go do it on an acre, half an acre, a quarter of a garden. Prove to yourself that it works.” At a national no-till conference, one farmer boasted he put cover crops on 15,000 acres. “He’s figured out how to do it.”
• The book “Managing Cover Crops Profitably” by Sustainable Agriculture Research and Education, is available online at www.sare.org/publications/.
• The Purdue University Cooperative Extension Service offers the publication “Midwest Cover Crops Field Guide.”
• Web sites: www.covercrops.msu.edu/; www.mccc.msu.edu/; www.bcscd.com; www.in.nrcs.usda.gov/technical/Soil%20Health/soil_health.html; web.extension.uiuc.edu/regions/ag/ag2.htm.