Cover Crops Can Provide Fall and Winter Pasture
By Heather Smith Thomas
Cover crops were traditionally planted to help hold the soil and prevent erosion when transitioning between different cash crops. They were often plowed under before planting the next crop—to add organic material and fertility to the soil. Today, farmers with livestock often select cover crops that can be grazed, adding additional benefits–feed for the livestock and the advantage of manure. Some cattle producers plant cover crop mixes simply to produce more late summer, fall and winter feed and may strip graze those crops to get the most benefit from them. In snow country they may windrow the forage in the fall, to make it easier for cattle to access under the snow.
Beef and Forage Specialist Barry Yaremcio (formerly with Alberta Agriculture and Forestry and now a ruminant nutritionist and production management specialist– Yaremcio Ag Consulting Ltd) helps farmers/ranchers increase livestock production and soil health. He says some farmers simply add different varieties of seed to establish an extra crop when planting a traditional crop, to provide more forage.
“They might be seeding oats or barley for silage, but at the same time add clover, winter wheat or another crop that will be available for grazing after the silage is harvested,” he said. Broadcast seeding grazing turnips, kale or forage rape between rows can also provide a crop for grazing later.
“The grazing brassicas (turnips, kale, forage rape, forage radish), sorghum and sudangrass hybrids, winter wheat or fall rye, winter triticale, etc. can provide high-quality forage late in the growing season. These species grow faster once the silage or green feed crop has been taken off, and provide fall/winter grazing,” said Yaremcio.
Total yields can be increased by adding cover crops, including various cocktail mixes of different species. A mix provides good diet for cattle, including a legume to increase protein and calcium content. Using different species can help balance the ration, reduce supplement costs, and take advantage of moisture and growing conditions at different times of year. This produces better yield as well as better quality forage available through the entire summer and fall. If one type of plant doesn’t do as well, some of the others might.
This is the advantage of cocktail mixes because you can include a species that can take the heat and withstand drought if it’s a dry year, and other plants that grow when it’s cooler, with more moisture. A good mix can reduce risk and help assure good feed for cattle, whatever the year might bring.
Extending the grazing season reduces production costs for cattle. Permanent pastures are usually best, but there are times it’s helpful to utilize annual crops to fill in some gaps or improve soil health before replanting a pasture. Kevin Elmy (Friendly Acres Farm, in east central Saskatchewan) consults with and gives presentations for producers regarding ways to improve pasture production and create regenerative agricultural management systems. Some forages that were earlier considered cover crops to plant between traditional crops (to keep the ground covered and prevent erosion and add fertility) are now planted just for grazing.
Elmy says the best balance in a cover crop—for grazing and future soil health—is to include a mix of grass, legume and broadleaf plants. “A good cover crop contains all three. A great cover crop includes a warm-season grass, cool-season grass, warm-season legume, cool-season legume, warm-season broadleaf and cool-season broadleaf. Diversity is the key,” said Elmy. This is the best diet for cattle because there is always something green, providing what they need, as well as feeding the soil biology.
“When seeding early in the season (with chance for frost), warm-season plants won’t do well. If you plant early, it’s best to get some cool-season plants growing, such as oats, barley, peas and sometimes other species like chicory or plantain. Grasses provide the most pounds per acre of forage and legumes will be the ‘gas’ you add to the motor–good nutrient quality for livestock and nitrogen-fixing for the soil,” he said.
“Broadleaf plants like brassicas should be used sparingly because they are non-mycorrhizal.” Mycorrhizal fungi form symbiotic relationships between fungi in the soil and plants. The fungi colonize root systems of host plants, providing increased water and nutrient absorption capabilities and the plant provides carbohydrates for the fungi, formed from photosynthesis, in a mutually beneficial relationship. Some plants, like brassicas, are highly resistant to mycorrhizal fungi and normally remain un-colonized by fungi.
“There are also some potential feed problems (like choke) with brassicas, and the fact they are too high in protein. You only need a few of these plants in the mix, to add diversity and protein,” said Elmy.
Protein balance is important, and so is sugar. “Researchers like Clayton Robins found that if you can keep the sugar-to-protein ratio in the rumen at least two to one, the rumen performs much more efficiently. Robins has actually gotten these levels as high as three to one, using some of the high-sugar forages.” The plant mix should have a few less brassicas and more grass, especially the energy-dense grasses.
“We’re also finding, through research, that to feed the soil biology we need to keep plants in a vegetative state (actively growing). Early in the year, cool-season grasses, broadleaf legumes, etc. are best, but as you get into summer and warmer nights you can transition into warm-season species. Later you can be switching back from warm-season to cool-season species,” he said.
You can also add a winter cereal, which will keep re-growing through the year, to facilitate rotational grazing. It’s important to determine your goals for the pasture. “Are you rotational grazing, or taking a cut of hay and then grazing regrowth? Your goal will determine the species you use for your annual or cover-crop mix,” said Elmy.
Using Cover Crops Improves Soil As Well As Forage
Grant Lastiwka (formerly a Forage Extension Specialist in Alberta and now with Union Forage), says some of the alternative cover crops can be very beneficial for livestock. “Conventional grazing systems often fall short because we either have an annual that must be planted and starts growing later in the spring and finishes growing sooner than perennial forages, or a perennial pasture that lacks productivity. Many pastures fall into that latter category and their ability to capture carbon (and water) is limited. Using cover crops that include a legume can help. Adding nitrogen also improves water use efficiency,” Lastiwka said.
Adding root crops gives ability to get down through hardpan and create root channels. “Research with alfalfa shows positive results—adding nitrogen (to improve water use efficiency), root channels (to aid water infiltration) and ability for plants to follow those channels thereafter. With the mosaic of species in a mix of plants, the grasses can derive nitrogen for themselves,” he said. Now people are looking at ecology of systems and grazing is part of that ecology.
Studies in the late 1800’s and early 1900’s measured the amount of erosion under different systems. “People started to see that if we cover the landscape to prevent erosion and have more water infiltration due to mass on the surface, we capture more water. A good grazing system or pasture must have litter; otherwise moisture runs off and you don’t have a functioning ecosystem. We need the sponge effect, cool soil (shaded by plants, rather than bare and baking in the sun), good infiltration (to keep raindrops from hitting the soil surface so hard), etc. Using a legume, a root crop and cool season grass with a user-friendly arbuscular mycorrhizal fungi (with the fungus penetrating root cells in a symbiotic relationship) makes a beneficial mix,” Lastiwka said.
Things To Be Aware Of When Grazing Alternative Crops
Keeping a balanced diet and avoiding health problems can be tricky when utilizing alternative crops. It’s wise to test the feed and know if there are health risks, or to determine what type of mineral or supplements should be added to the diet to make them work.
Yaremcio says producers who plant forage brassicas like turnips, kale (or late-germinating canola crops for grazing, silage or green-feed) may find nitrogen content of the soil quite high. Nitrogen may come from commercial fertilizer or manure applied to the field. Nitrogen accumulation in some of these crops can be sufficiently high that intake must to be restricted to prevent poisoning.
In fields with high sulfur, some plants take it up. “Brassicas accumulate sulfur. We’ve seen feed test results with sulfur levels in the 0.6 to 0.8% range. Sulfur content in a ration (including sulfur from water) should not exceed 0.4% or it reduces rumen pH. Bacteria responsible for producing thiamine are very sensitive to low pH and die off. A shortage of thiamine can cause serious problems and death of cattle,” he said.
“In many parts of Alberta and Saskatchewan a few years ago, some canola crops did not germinate until rain came in July and early August. It was in full bloom/early pod stage when cut for silage and green feed. It was excellent feed, at 16 to 17% protein, great energy and good levels of calcium, phosphorus and magnesium, but sulfur and nitrate levels were high. The forage had to be blended down with other material to make it safe to feed, or control measures such as electric fence to limit the amount of canola consumed daily. Alternative crops require awareness, and sometimes more management than grazing conventional forages,” he explains.
“If you are planting some of these crops for late season grazing, feed testing is very important. With nitrates there may be no warning; you just suddenly find a dead animal. ‘Polio’ takes a bit longer, but the outcome can also be dead animals.”
Immature crops or crop regrowth have low fiber, and many brassicas and other companion crops have very low fiber levels. Without adequate fiber, manure becomes loose, due to high water content and rapid movement through the digestive tract. It helps to feed some high-fiber roughage such as slough hay or straw to increase dry matter content and reduce feed passage rate. “Animals that consume one or two pounds a day of high-fiber material have better digestive efficiency for high-quality feeds, and greater opportunity to extract the nutrients before they go out the back end,” said Yaremcio. In some of these crops, magnesium levels can be low. Low magnesium, especially if potassium levels are high, could lead to tetany and downer cows.
It may take cows a few days to adjust to different taste or texture when starting to graze cover crops. “Sometimes cows accustomed to really good pasture are fussy in what they want to eat. If you suddenly switch to a cover crop it may take a few days—and a little tough love—to get them to eat the alternate crop. If you don’t see them really going after it by the second or third day, you need to re-evaluate whether the cows will eat it,” he said. If you decide to try an alternate crop, talk to someone who has done this or knows about various forages, to get some suggestions and guidelines.
One Farmer’s Experience With Cover Crops
Kansas farmer Gail Fuller experimented with no-till farming during the 1980’s but didn’t ask for enough advice. “I was tired of erosion, and went completely no-till cold turkey, but still had erosion issues due to mismanagement,” said Fuller. “We were following corn with soybeans so there was no residue, no carbon added to the soil. The erosion got worse,” he said.
Then he attended a conference called No-Till on the Plains. “They were talking about cover crops. I tried those but no one I knew was doing it. Then we had severe drought in 2000 and no income. The first thing that got cut was the cover crops,” he said.
He went back to what he was doing earlier, but it stayed dry several years, yields declined and erosion got worse again. “That’s when I realized that we’d been headed the right direction with the cover crops. Instead of taking things out of rotation, we needed to be adding things into it,” said Fuller.
In 2003-2004 he went back to cover cropping. “Only this time, instead of using a monoculture, we used mixes—trying to imitate Mother Nature. I started with a few plots next to our feedlot. I quickly realized this created a lot of good, cheap forage.”
He went to more conferences and listened to people like Dave Morell, Gabe Brown, Neil Dennis, Ken Miller, Doug Peterson, Jim Gerrish and Greg Judy. They were mob grazing. “Gabe became my mentor. Soon I was moving my cattle 6 to 8 times a day. Now I want cattle on all the acres I can get them on—at least every 2 or 3 years I want cattle to go across a field at least once,” Fuller said.
Now most of his mixes contain 15 to 20 species, trying to imitate native tall grass prairie. “We want as many plants as we have on the prairie—forbs, legumes and grasses. Agriculture in recent decades moved away from a natural system, and we must re-learn the things that work. We’ve forgotten earlier wisdom, but it’s all been done before. With the exception of mob grazing, most of what we are trying to learn today is what grandpa or great-grandpa did. They used cover crops to grow legumes and feed cattle,” said Fuller. Livestock were used extensively to keep soil fertile and productive, before the days of chemical fertilizers, and before farmers were taught about the benefits of monocultures at agricultural schools.
“Kids coming out of the university system today don’t understand basic truths about best ways to manage land and livestock. They come home from university and see me moving fence by hand and doing things that look like a lot of work,” said Fuller.
The sad thing about “modern” agriculture is that farmers/ranchers usually have to keep expanding or trying to produce more, just to break even or pay the bank, whereas taking good care of a small piece of land can create a more sustainable living. Integrating crops and livestock makes it work.
