Farmers learning cover crop ropes
By Jean Caspers-Simmet
Date Modified: 05/28/2013 8:04 AM
WAUKON, Iowa — Given the drought and a winter that never seemed to end, Allamakee County farmers are pleased with the result of aerial seeding cover crops into standing corn and soybeans, said Jake Groth, soil conservationist with the Natural Resources Conservation Service in Waukon.
Until last year, farmers using cover crops generally seeded cereal rye or winter wheat after corn silage and then chopped or baled it in the spring, Groth said.
Farmers with CSP and EQIP contracts weren't getting cover crops established timely enough to gain all the benefits so they looked into having cover crop seed flown onto standing corn and soybeans in August.
Groth talked to Brian Berst, a pilot with Klinkenborg Aerial Spraying in Parkersburg. Berst said he needed at least 200 acres in the area to make it pay.
"We lined up 1,500 acres in Allamakee, Clayton and Winneshiek counties," Groth said. The Allamakee County Soil and Water Conservation District partnered with SWCDs in the other counties.
Application costs were about $15 per acre plus seed costs.
Cover crop mixes included two bushels of cereal rye per acre; a blend of two bushels of oats and five pounds of tillage radish; and a blend of 15 pounds of annual rye grass and two pounds of tillage radish. Some farmers in Clayton County used a mix of 45 pounds of cereal rye, six pounds of red clover and three pounds of tillage radish.
"We had success on all of them, but a lot of it depended on what we got for rain after they were seeded," Groth said. "In some parts of the county, it just didn't rain, and the oats and radishes didn't germinate until October and didn't have enough time to grow before they were winter-killed. Others fields got a quarter of an inch of rain right after seeding and then temperatures were 90 degrees, and the radishes fried. Overall, things did pretty good considering the conditions. There were some spots that were not spectacular, but some stands were phenomenal."
Groth, who farms with his father, Chuck, near Decorah, aerial seeded 15 acres of cereal rye and 25 acres of oats and tillage radish into standing corn.
"Some of it was spotty, but it was successful," Groth said. "It was nice to see something green in December."
The oats and radishes were from 8 to 18 inches tall when the corn was combined. At the end of the year, where the tillage radish got full sun, tubers were 9 to 13 inches long with the tap roots twice that length. In the middle of standing corn, tubers were 4 to 6 inches and some were even 8 inches long. The tap roots went down 12 to 16 inches.
"We should be getting through the compaction layer with that," Groth said.
A wind storm caused a corn hybrid to goose neck in one field and the rye planted underneath didn't do well. In Clayton County, herbicide carryover was an issue in some spots.
Cover crops increase soil organic matter, loosen soil, provide root channels for corn and soybean roots, increase water holding capacity and scavenge nutrients, Groth said.
Many producers receive cost-share from EQIP, CSP or the state cost-share program to plant cover crops, Groth said, but some farmers recognize the benefits and are planting them without financial incentives.
This year Allamakee County farmers will aerially seed 1,800 acres of cover crops through the SWCD. Of that, 800 acres will be oats and tillage radish. New for this year are a rye grass, tillage radish and hairy vetch mix and a cereal rye, clover and turnip mix.