Cover crops can improve forage systems
“In a forage context, growing multiple crops together increases biodiversity, productivity and nutrition, as well as improves upon sustainability and soil health,” said Agri-Food Canada Research Scientist Jillian Bainard.
Bainard was featured as a speaker in a Beef Cattle Research Center webinar titled, “Integrating Cover Crops into Forage Operations: Risks and Rewards.”
“We have a few goals and strategies when it comes to utilizing cover crops and increasing forage production,” said Bainard.
“Our overarching goal is to enhance industry sustainability and improve production efficiencies,” she said. “We also want to enhance feed and forage production, improve management practices, maintain nutritional quality, identify optimal strategies and quantify benefits of integrated systems.”
Bainard explained, to reach these goals, she and her colleagues have studied numerous practices in relation to increasing forage productivity via cover crops.
“We have looked at utilizing various polycultures to increase production including winter polycultures,” according to Bainard.
Bainard noted the team has also researched cover crop spacing for weed control. By studying different spacing between plants, they were able to determine there was no difference.
“We have looked into soil microbiology ecology in forage cover crops,” said Bainard. “We also have studied swath grazing forage polycrops as a means of increased production.”
Bainard explained soil health can be very hard to define because it means different things to different people, and as a researcher, she works towards pinpointing a more exact definition of soil health.
“Soil health often means different things to different people because everyone has different priorities,” said Bainard.
According to United States Department of Agriculture (USDA), soil quality is defined as the continued capacity of soil to function as a vital living ecosystem that sustains plants, animals and humans.
“This definition speaks to the importance of managing soils so they are sustainable for future generations,” said USDA. “We need to remember that soil contains living organisms that, when provided the basic necessities of life − food, shelter and water perform functions required to produce food and fiber.”
“Only ‘living’ things can have health, so viewing soil as a living ecosystem reflects a fundamental shift in the way we care for our nation’s soils,” said Bainard. “Soil isn’t an inert growing medium but rather is teaming with billions of bacteria, fungi and other microbes that are the foundation of an elegant symbiotic ecosystem.”
“Mixtures can increase biomass in comparison to some monocultures,” said Bainard. “Some monocultures such as corn and oats were shown to have higher biomasses than mixtures in field trials.”
She noted it is important for producers to understand more does not always equal better when it comes to choosing cover crops and mixtures.
“Adding more species may not always mean advanced productivity but there will be a more stable biomass,” said Bainard. “Field trials show there is not much improvement after four species.”
“Coupled with the production rewards associated with cover crops, there are some risks and difficulties associated with the practice,” Bainard noted.
She explained oftentimes crops recommended by seed companies are not necessarily suited for local conditions.
“One of the biggest challenges comes with discrepancies between seeding,” said Bainard. “It can be extremely challenging to plant seeds of different sizes and depth needs.”
“Forage quality can be maintained or improved, compared to monocultures, depending on the mixture,” Bainard explained. “Higher protein or fiber mixtures can assist in improving nutrition.”
“Species can be selected for inclusion in a mixture based on their nutritive quality,” said Bainard. “However, mixtures with four or more species have a limited effect on improving plant nutrition,”
She explained brassicas, such as forage turnip, have low acid detergent fiber, low neutral detergent fiber, high organic matter digestibility, high crude protein and high calcium, iron and phosphorous.
Bainard noted legumes such as hairy vetch have high organic matter digestibility and high crude protein.
“There are some risks associated with these mixtures,” Bainard stated. “Mixtures high in brassicas may have toxic levels of nitrate and sulfate.”
Getting the right mix
“Getting the right mix will impact productivity,” she explained. “We can use different mixes for different purposes.”
Bainard used balance, weed control and nitrogen fix mixes to show how different types of plants can achieve different goals.
“A well-balanced mix will help producers do just that − balance their productivity and diversity of their forages,” she noted. “A good balanced mix can include oats, barley, peas, hairy vetch, forage radish and Hunter brassica.”
“Lots of producers want to control weeds in their forage systems,” Bainard said. “We have to be very careful with weed control as the goal because cover crops themselves can become weeds if not managed correctly.”
She suggested using oats, peas, forage radish, Hunter brassica and Winfred brassica as a mixture to control weeds.
“Nitrogen in any crop system is vitally important,” Bainard stressed. “We can use cover crops to increase nitrogen levels in our forage systems.”
She noted using combinations of peas, hairy welch and berseem clover can help alleviate nitrogen issues in a forage system.
Callie Hanson is the assistant editor of the Wyoming Livestock Roundup. Send comments on this article to firstname.lastname@example.org.