MINNEDOSA, Man. – It’s never easy to make a speech when the wind is gusting to 75 km-h, but Lindsay Coulthard did his best as he stood in an alfalfa field at the Manitoba Zero Tillage Research Association (MZTRA) farm.
Over the wind, Coulthard told the 50 people at the association’s summer tour about the alfalfa crop rotation at the farm between Brandon and Minnedosa.
Over a period of six years, the MZTRA compared a rotation of cereal-pea-canola-cereal-flax-canola to a rotation of alfalfa for three years, followed by cereal-flax-canola.
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After crunching the numbers, they found that the cereal crop following the alfalfa required 66 pounds per acre less nitrogen, but still produced the same yield of winter wheat in the annual crop rotation.
More significantly, they evaluated the economics of using the alfalfa for grazing and hay production over that six-year period and found the alfalfa rotation produced an average return of $40 per acre versus $35 for the annual crops.
That’s why the MZTRA plans to do more work on the economics of a swap arrangement between straight grain farmers and straight cattle producers.
“I’ve had a couple of requests from producers who are thinking that way,” said Coulthard, manager of the zero-till farm. “And we’ve also have had some input from people at the Manitoba Forage Council, who are thinking that there’s opportunity here that we should take advantage of.”
Everyone benefits
The logic behind the swap, said Andrew Kopeechuk, livestock and forage co-ordinator at the farm, is that both producers benefit.
“The grain guy swaps out a quarter section to put into alfalfa for three years, he gets the added benefit, after those three years, of having less fertilizer input and possibly less chemical,” Kopeechuk said. “The cattle guy gets a quarter section of hay … and then the cattle guy can swap a quarter section … to throw annuals on (his land) for three years.”
Although it will take some work with a calculator to figure out the potential benefits of such a swap, having alfalfa in a rotation does more than just fix nitrogen, Coulthard said.
“We feel there’s a real good benefit from the alfalfa, in terms of water balance,” he said. “In the year following the alfalfa termination, we could go out in those fields at virtually any time and do our spraying or our seeding, where the fields in the annual rotation were too wet to get on.”
Alfalfa pushes down a deep tap root, Coulthard said, and when the alfalfa is killed off with glyphosate, its root decomposes and provides a natural drainage channel, which would be useful in regions that flood frequently.
The hard part is quantifying how much of a difference alfalfa makes for water infiltration, because drainage and topography are highly variable on the zero-tillage farm.
“We’re going to start a project with some scientists at the University of Manitoba that are going to try and quantify that accurately,” he said.
On top of drainage, Coulthard noted that weeds are less prevalent in the annual crop, following the alfalfa.
“We haven’t see any real issues with perennial weeds,” he said. “(And) wild oat numbers (were) reduced in the three years following the alfalfa.”
