MOUNT CARROLL, Ill. — Justin Rahn has grazed his cattle herd on cover crop fields for several years.
Justin and Ellen Rahn manage a cow herd on their 1,200-acre Carroll County farm where they grow corn, soybeans, alfalfa and rye.
“I run almost 80 fall-calving cows that will start calving on Aug. 20 and I also calve just over 50 cows in the middle of January,” said Justin Rahn during a field day organized by the Practical Farmers of Iowa.
Practical Farmers of Iowa, based in Ames, was founded in 1985. One of the group’s core values is an open exchange of knowledge and information benefiting farmers and communities.
It is a member-led organization where farmers hold events, conduct on-farm research and steer the programming.
“I’ve been working with Doug (Linker) over the last four to five years with grazing cattle on his fields,” Rahn said. “Doug’s crop rotation is corn, soybeans and wheat.”
“We have the same interests and I wanted to start trying cover crops, so it was a natural fit,” neighboring farmer Doug Linker explained. “We like to bounce ideas off each other and we were some of the first farmers in this area to plant cover crops.”
Rahn talked about Linker’s wheat field that was combined two weeks ago.
“I seeded this wheat field last fall, and at the end of March, I blew on 8 pounds of medium red clover and 4 pounds of Balansa clover with a Valmar seeder,” he explained. “After the straw was baled, I seeded the field with pearl millet, Dwarf Essex rape and Barkant turnips.”
Rahn plans to turn cows into the field about the first week of October.
“Any day you don’t have to start a tractor in the livestock business is a good day,” he said. “I try to keep the cattle out here as long as possible and last year they were in a field until right before Christmas because we didn’t have snow.”
Any day you don’t have to start a tractor in the livestock business is a good day.— Justin Rahn, farmer, Carroll County
“The cattle bring the soil health full circle and I’m really happy how the grazing is going,” Linker added. “I encourage everyone to find a way to get cows or sheep on your ground.”
With the relationship developed by Rahn and Linker, Linker gets the benefit from the manure from the cattle and the nitrogen from the cover crops and Rahn has more land to graze his cattle.
“They’re not making more dirt, so if I can work with my neighbors, it’s a no-brainer,” Rahn said.
“I have worked with Doug, Justin and Ellen for a few years,” added Laura Lant, agronomist with Midwest Grass and Forage. “One of my favorite things about them is their willingness to try new things and not do the same things because that’s how they’ve always done it.”
In previous years, Rahn only seeded medium red clover.
“The reason I pushed Justin to try Balansa clover is because Doug is after maximum nitrogen and soil health,” Lant said. “So, the more diverse species we have in a mix, that helps to improve organic matter and soil health much quicker.”
In addition, Lant said, Balansa clover is a low-bloat option.
“We also cut the red clover rate back because we used raw seed and you get more seeds per pound,” she said. “We cut the rate 4 to 6 pounds, which more than covered the cost of adding Balansa clover.”
Instead of Purple Top turnips, Rahn planted Barkant turnips, which is a forage turnip.
“They have a slightly smaller bulb and they produce two to three times more top growth,” Lant said. “The cattle will graze the top growth first, and once it freezes, the cattle will get down to the bulbs.”
Dwarf Essex rapeseed was selected for the field because of its ability to suppress weeds and soybean cyst nematodes, Lant said.
“I also like it for its cost-effectiveness,” she said. “It’s about half the cost of turnip seed per pound and it gives you just as much top growth.”
In another field, Rahn planted Teff grass on Memorial Day.
“Teff is a fine-stemmed grass that needs to be on top of the soil and pressed in,” he said. “But I did not use a cultipacker, so I got a lot of crabgrass and Johnson grass.”
“We choose Teff because of logistics and equipment,” Lant noted. “Teff is a lower-yielding summer annual. However, it will make the best quality dry hay of the summer annuals.”
Rahn has already harvested one crop of Teff.
“It is on the same rotation as my alfalfa, so I’m hoping to get two more crops and then this field will go to wheat,” he said.
Teff prefers to grow in dry, well-drained soils, Lant said.
“If you have a field right beside a river or creek bed that’s a little swampy, it won’t work there,” she said. “Teff has about 1 million seeds per pound and the key to get it established is don’t bury it too deep.”
“When I took this farm over, the tillage practices by the previous farmer were three passes in the spring with a disc, so all the top soil was gone off these hills,” Linker said. “We’re trying to repair the damage that was done by trying to keep the ground covered as much as we can.”
Adding cover crops into a crop rotation to improve soil health, Linker said, is a long-term process.
“I’m due for new soil testing, so it will be interesting to see how they look,” he said.
Linker’s goal is to use fewer inputs for growing crops.
“I’m trying to use less diesel fuel and less nitrogen by growing our own nitrogen with cover crops,” he said. “I’ve cut back 50 to 60 units of nitrogen because of cover crops and I think we can go more.”
The next step for Linker is to start tissue testing his crops.
“I want to see what we really have,” Linker said. “I’m cutting inputs and I’m seeing yields as good or better.”
“I don’t want to be stagnant and both Justin and I like to try different things,” he said. “The crop yields are great, so we’re trying to net the same or more on less purchased fertilizer.”
For more information about the Practical Farmers of Iowa, call 515-232-5661 or go to www.practicalfarmers.org.