While cover crops are not a new concept for farmers, Erika Lundy said she has been impressed with the amount of adaptation and implementation she has seen over the past few years.
Lundy, a beef specialist with Iowa State University Extension, said one of the major benefits of cover crops is providing high-quality forage for cattle with high protein and energy levels. But for those who are grazing their cover crops, it would be best to supplement that diet.
“Dry matter and fiber levels are often relatively low and are the limiting factor in determining how much a beef animal can eat,” Lundy said. “Therefore, supplementation of some kind is often needed. In general, (Extension) recommends offering dry hay when grazing cover crops.”
Whether it’s a calf or a cow or the stage of production also should determine what kind of supplementation the animal needs.
Iowa State field agronomist Rebecca Vittetoe said she has also seen increased interest in cover crops as a source of forage, especially in times when forage has been more limited. However, like any crop, it’s up to Mother Nature how effective it can be.
“With cover crops we are at the mercy of Mother Nature,” Vittetoe said. “Some years they can provide great forage and other years not so much of any forage or grazing.”
The most popular cover crop to be seeded in Iowa continues to be cereal rye for overwintering and spring grazing, while Vittetoe noted oats can provide good growth for fall. Whatever an operation decides to do, she said it is important to stay flexible.
“It is important to be flexible and make adjustments to the operation,” Vittetoe said.
“Maybe you graze longer in the spring and plant a shorter- season corn hybrid or soybean variety. Some farmers are looking at including a summer annual forage to adjust their crop rotation to better accommodate being able to graze or use their cover crops for forage.”
Lundy noted it is common for farmers to plant combinations of cover crops for their animals for multiple benefits. Doing some cereal rye combined with oats can offer grazing options in the spring and fall seasons, while another mix revolves around small grains and a brassica.
“The addition of a brassica improves forage quality, and a deep tap root also offers some compaction relief,” she said.
Lundy said one of the reasons some farmers haven’t turned to cover crops is labor, according to survey results from the Iowa Beef Center.
“A farmer wears many hats, so a major obstacle right now is having enough time to get the cover crop established in a timely manner during the already busy fall months during harvest,” she said.
Another obstacle is cost and finding the true benefits to what cover crops can bring to a field. The typically discussed cover crop benefits, like erosion control and weed suppression, are hard to put a monetary value on, whereas using the crop in place of some feed can be seen in a spreadsheet.
“With grazing or harvesting the cover crop as a forage, the return for investing in a cover crop is realized in the short run, compared to having to wait a few years to see a boost in the soil fertility or a decreased need for herbicides to control weeds,” Lundy said.