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Frost Seeding Cheaper, But Results Can Be Sketchy

“If I had some really rough land and the stand was really bad and I wanted to get some legumes in, I might try it on some parts. I certainly wouldn’t go out and seed 160 acres that way.”

– jane thornton

There are two ways of reviving pastures that are past their prime.

The traditional approach involves a lot of diesel, equipment and hours on the tractor.

Another less well-known strategy requires little more than a bag of alfalfa or other legume seed, a device for scattering it over the ground – and tightly crossed fingers.

A study by Manitoba Agriculture in 1999 – at a cost of $800 – sprinkled alfalfa, clover and trefoil seed on pastures in two locations, St. Malo and Zhoda, using an ATV-mounted broadcast grass seeder in the fall and early spring.

Cattle were kept off the five-acre sites until late the following June. At a seeding rate of 10 pounds per acre for 30 to 45 seeds per square foot, the Zhoda pasture saw a catch of two to four plants per square foot, while the St. Malo pasture ended up with nothing at all.

The study’s authors concluded that frost seeding should only be attempted on small plots where no other means of establishing legumes is possible, such as very rocky ground that can’t be broken up, because the results may vary widely.

That’s why optimists need only apply when frost seeding legume forages into a beaten-up pasture, according to MAFRI pasture and rangeland specialist Jane Thornton.

“Some guys can make it work and some guys can’t,” she said. “If I had some really rough land and the stand was really bad and I wanted to get some legumes in, I might try it on some parts. I certainly wouldn’t go out and seed 160 acres that way.”

A 30 per cent catch is about the best that can be expected, so deciding whether to try it depends on the price of alfalfa or other legume seed, and one’s ability to cope with disappointment.

The thinner the stand, the better the odds that the seeds will find their way into the ground or get enough seed-to-soil contact to germinate.

“If the seed just sits on top of the soil or the litter or the grass, it’s not going to do anything,” she said, adding that some ranchers have used the hoof action that comes with high stock density to grind the seed into the soil.

Getting the seed onto the ground early in spring can have

its pros and cons, she added. Although alfalfa can take a light frost, when the emerging plants are young a hard frost could wipe out the seedlings at a vulnerable stage.

Keeping the legumes alive over their critical first year requires some caution on the part of the grazier. Being in too big of a hurry to put animals on it once it comes up, or neglecting to allow for an adequate rest period, can erase whatever gains were accomplished, she said. It’s better to wait until growth is between six to 12 inches high before letting livestock onto the pasture, she said.

As in all things, you get what you pay for. To get a good, thick,

healthy stand, spraying out the existing vegetation and drilling the seed into the ground may be more expensive, but it stands a better chance of succeeding, said Thornton.

Bill Gardiner, a pasture and rangeland specialist based in Dauphin, has had some success with frost seeding along fence-lines using an ATV and broadcast seeder. The best time to try it is in early spring, just when the snow is disappearing and the soil still has a bit of moisture in it, he said.

One of the best cases that he has seen involved seeding by air prior to logging in a forested area, where the equipment ground the seed into the soil in the course of harvesting the trees.

“I’ve seen good results with that. It’s always better if you have something to trample the seed into the ground afterwards,” he said.

The forage species used would depend on the wetness of the pasture area, but a “shotgun” approach using a mixed bag of seed generally has better odds of success.

“It’s one more option,” said Gardiner. “If you’ve got stony land, the less you work things up the better. So surface seeding or frost seeding has some merit in those situations.” [email protected]

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