By Meghan Filbert
Think of winter and summer annuals as links in your forage chain. These forage species can be used to diversify crop rotations and provide a foundation for integrating livestock into your crop fields — while putting gain on animals at a time when perennial pastures need rest.
“My main purpose for planting annual forages is to find a way to do what I love: livestock farming,” says Luke Wilson, farming near Prairie City in Jasper County, Iowa. “My goal is to bring grazing into my family’s row crop rotation.”
To do this, Wilson incorporates a full year of annual forages every third or fifth year into his family’s corn and soybean rotation. Active in the Iowa Forage and Grassland Council, he hosted a bus tour in November 2018 as part of the IFGC conference. Attendees watched cattle grazing stockpiled oats and turnips.
Wilson’s acres are located on marginal, sloping ground near Lake Red Rock, where he has witnessed a positive response from planting diverse annual forages and integrating livestock. The annuals are grazed by heifers or cow-calf pairs, which are purchased or home-raised, and developed on forage with a total mixed ration. Cattle are then sold as bred heifers weighing 1,150 to 1,300 pounds through the Knoxville Livestock Market.
Diversifying crop rotations
Wilson’s preferred mix of forage annuals consists of Green Spirit Italian ryegrass, forage oats and brassicas. The brassicas are hybrid varieties that put on less bulb and more leaf, and provide multiple grazings. The mix is no-till drilled in late March or in April at a rate of 25 pounds per acre, and costs $1.40 per pound, totaling $35 per acre in seed cost.
The oats come on first, ready to graze 60 days after planting. Then the Italian ryegrass fills in, providing high-quality grazing throughout late spring and fall. The brassicas supply the majority of forage production during summer.
After dining on oat stubble, Wilson’s herd continues to graze on ryegrass and brassicas until October or November. Italian ryegrass winter-kills much of the time. With adequate snow cover, however, it will come up in the spring, providing another grazing or harvest opportunity before termination prior to corn planting.
Wilson supplies 40 units of nitrogen at planting, then again in June and August. “In June, nitrogen helps feed brassicas and rye after the oats have shut down, since they consumed the majority of initial nitrogen applied at planting,” he says. “The most important nitrogen application is in August when nights start cooling off. This helps boost forage production in the fall, but also helps root systems develop to improve durability and winter survivability.”
Wilson has applied nitrogen in many forms — commercial, ammonia sulfate, urea, biosolids and chicken litter.
Mitigating summer slump
For Mark Yoder, of Leon in Decatur County, Iowa, planting summer annuals is a way to provide his cow-calf pairs with forage during the “summer slump” — when cool-season perennial pasture growth slows during hot weather.
Last year, he planted 48 acres of summer annuals (instead of soybeans) on May 31. The annuals were no-tilled into a field that had previously been growing a cereal rye and wheat cover crop. His 23-way mix from Green Cover Seed cost $33 per acre, which he learned was more than he needed.
Yoder says, “23 species is way too many. If we would have had fewer species, the sorghum and millet would have been thicker, especially for the second grazing in September.”
Due to complementary growing patterns, annuals are ready to graze when perennials need rest, and vice versa. Annuals help fill in forage gaps in grazing systems. Yoder’s cattle grazed perennial pastures from June until late July 2018, then were turned into the annuals.
“When other people were running out of pasture, we had cows in the field eating forage that was 8 feet tall,” Yoder says. This fresh forage allowed his drought-afflicted pastures to rest at a critical time, and the Yoders were able to make an extra cutting of hay from the rested pasture. This strategy also lets farmers stockpile perennials, such as fescue, for winter grazing.
Yoder applied 50 pounds of nitrogen and 20 pounds of sulfur on the annuals on June 29, but he wishes he would have applied it earlier to boost grazing potential. Sixty cow-calf pairs got a total of 45 grazing days out of this mix, grazing from July 20 to Aug. 19 and then again from Sept. 19 until Oct. 4. No supplemental feed was needed during these grazing periods.
The 48 acres of annuals were split into 10 paddocks with single-strand electric fence. Yoder spent 15 minutes every three days rotating the herd to the next paddock. A fenced-in alley allowed cattle to access water from a nearby pond.
Strip-graze if possible
Grazing experts recommend strip-grazing to best use annuals. “Annuals will bounce back and grow rapidly if you’re diligent about strip-grazing,” Wilson says.
It comes down to time and water; it’s labor-intensive and might not be economical for everyone. Also, livestock must have water access from each strip, which can become an issue. Wilson has different gates opening into a timber pasture where water is located, and cattle can always get back to that watering point.
Every couple of weeks, Wilson rotates his herd from annuals to perennials and back again. “In 2018, I was shorter on time, so I grazed cattle on 50 acres of annuals for two weeks, then rotated them with three perennial paddocks,” he says. “I know when I let them continuously graze for a week or longer, I’m giving up some production.”
He doesn’t recommend turning cattle out on annuals for months at a time because this can damage plants by selective grazing.
Thinking ahead to the fall, a sequence of winter annual small-grain species can be seeded to provide forage over winter and early spring.
According to Anibal Pordomingo, an animal scientist from Argentina who led a workshop for Practical Farmers of Iowa last fall, the potential for animal growth on winter annuals exceeds any other forage resource during that time period and can provide gains of 1.8 pounds per day in finishing steers. This gain is less costly than if feeding hay or silage. Cereal rye, barley, wheat, triticale and annual ryegrass are all viable winter forage options.
Mellower soil a result
One of the benefits Wilson sees to diversifying corn and bean rotations with forage annuals is the improved texture of the soil. “The next spring, we have the most mellow soil, and are able to no-till corn right into it. It works out so beautifully. The soil is stable from root mass, but you can also pick it up and it’ll crumble in your hand. That’s what we strive for, and it doesn’t take machinery to get the mellow soil, just the plants and the livestock.”
Wilson has been able to find a way to keep doing what he enjoys while breaking the mold in Iowa. “It’s easy to feel as though you have to raise corn or soybeans,” he notes. “But there are so many forage species you can use. And if you already have livestock, you’re going to find a way to be successful while thinking outside the box.
“With the use of annual forages, it’s exciting to envision a forage chain that provides season-long grazing opportunities while diversifying the landscape and benefiting the soil.”
Filbert is PFI’s livestock program manager.