Perennial legumes, especially alfalfa, bring benefits to a cropping system that can override initial concern many growers may have when it comes to the economics of the practice.
Around the world, some countries are concerned about the lack of local available water for growing their own forage. “There is a growing trend for longer-term commitments when purchasing forages and alfalfa of perennial legume by other countries,” said Lastiwka. This can provide Canadian grain and oilseed producers with a more economically viable alternative crop.
Growers can also seed their stand into a perennial legume, have custom representatives come in and harvest it, and get a better price per acre and per tonne for forage legume. “This is happening and it’s a trend we feel is on the rise,” said Lastiwka.
A perennial legume provides an opportunity to bring a very different type of plant into a crop rotation system. This can break disease cycles of existing cereal and oilseed crops. It may also address some herbicide resistance issues and cut fertility costs, as alfalfa can fix its own nitrogen.
On the negative side, annual crop diseases seem to be on the rise. “We worry about general diseases that can occur with a short rotation that survive through the two years between oilseed crops — like fusarium, aster yellows, skull, net blotch, black leg, club root and even insect issues,” said Lastiwka.
“When we look at breaking that rotation with a perennial legume, we make an inhospitable environment for those diseases and insect issues.”
Work done by Neil Harker at Lacombe showed the opportunity of breaking some wild oat herbicide resistance issues by looking at a number of alternatives, such as a perennial crop like alfalfa.
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“When that was looked at with wild oats, excluding wild oats herbicides for three years, done at eight locations across Canada (from Alberta to Quebec), they found alfalfa as an alternative, along with a double seeding rate of winter cereals, allowed for cutting silage — providing effective wild oat management without wild oats herbicide,” said Lastiwka.
This system dramatically reduced selective pressure of wild oat resistance to herbicides and helped growers delay wild oats resistance evolution.
Lastiwka looked at existing fertility opportunities with a perennial legume. “Even with a very short rotation with perennial legumes, it’s surprising, within the two or three year crop production system, how much nitrogen can be harvested and made available to resulting crops on that land,” he said.
The University of Manitoba’s Dr. Martin Enns found with a no-till approach, the release of nitrogen is slower than when the alfalfa stand is cultivated under.
According to Enns’ study, the slow release of nitrogen with no-till can last up to seven years (with some based on nitrogen coming out of the roots). “He also felt some was due to the root channels,” said Lastiwka. “Also, the root system improved the productivity longer, potentially up to 10 years — doing well with this good highway in the soil to travel.”
Alfalfa can go as deep as 20 feet into the soil. The majority of the effect alfalfa would have on the soil would be below the cultivated line, but, in many situations, the soil is only cultivated about three feet deep.
“Work done by Bruce Coulman and Paul Jefferson in Saskatchewan show that our hay fields have been dropping over time, part of which they felt was due to very good prices for cereals and oilseeds resulting in many producers letting their stands get older with lessened quality,” said Lastiwka.
“We’re seeing a higher price paid for forages, in general, because of a market and lack of acres. But, having legume stands seeded doesn’t mean you have to harvest it yourself or that you won’t have opportunity to market it, as long as you’re doing it right.”
Lastiwka advised consulting with all parties involved in advance to determine what they are looking for, what they will pay for it, and even if they will harvest it for you.
“Productivity of alfalfa forage stands are related to their management and that is a very important factor,” said Lastiwka. “The more skilled the management, the more the potential.”