Experimenting with irrigated cover crops

The White Lake Hutterite Colony near Nobleford, about half an hour northwest of Lethbridge, Alberta produces both beef cattle along with annual crops, and in recent years they’ve started looking at growing cover crops under irrigation.

Cattle manager Jerry Hofer has been trying several different species to be seeded after taking off soft white wheat as a silage crop. He says for what they want for the land and cattle, the best so far is oats usually grown in combination with another forage species.

“We have tried triticale, and want to try some rye next year because rye is a little more hardy and it doesn’t head out the first year,” Hofer says. “And rye can handle tougher weather. But oats seem to be the best for a cover crop, and it grows fast.” They have tried winter wheat in the past, but decided it didn’t work as well.

Hofer says they’ve also tried seeding blends including turnips with other forage species. One concern with turnips, especially if there is a high percentage in the forage mix, is that the high-protein crop “runs through the cattle too fast; the cows get very loose manure.” In 2021 they kept it simple and seeded a mix of turnip with oats, “and that was our best crop yet,” he says.

Hofer says it’s important to find the proper seeding ratio between the two crops. “If you put in too many oats they choke out the turnips.” For the cover crop this past year they seeded 20 pounds of oats along with Hunter Goliath turnips. This forage turnip has more foliage and more of a taproot and not much of a bulb.

They planted the oat/turnip blend under three irrigation pivots in midsummer and then last fall turned the cattle in to graze two of the pivots. There was some concern they might waste forage.

“But after the cattle grazed the forage blend on those two pivots until January, you couldn’t even tell that anything had been seeded there,” he says. “That’s how nicely they cleaned it off.”

The oat/turnip blend grown under the third pivot was cut and left in windrows for swath grazing. “Some of it the cows didn’t eat it until weather got cold.” says Hofer. “But eventually they did clean it all up.”

Hofer says that along with providing winter grazing for the beef herd, all the urine and manure left behind should help improve the soil texture and fertility.

In an area where kochia is a problem, Hofer says rye might be a better cover crop option on some fields. “The rye will actually kill the kochia. Rye gives off some kind of poison in the soil that kills it.” He’s referring to research that shows one of rye’s strengths as a cover crop is weed suppression. Along with this “allelopathic effect,” rye’s vigorous growth outcompetes weeds while the crop grows. If left ungrazed it results in plenty of crop residue for a physical barrier against weed growth after the crop dies.

Short winter feeding

Hofer says the objective of cover crops is to extend the grazing season. “We want to get away from feeding cows by having them graze longer and feed themselves.”

The White Lake Hutterite Colony is trying different combinations for forage species to be used as cover crops and fall/winter grazing. Oats and turnips (above) had a really good fit under irrigation on their farm in 2021 providing excellent feed for cattle right into 2022.

photo:
Courtesy Aaron Hoffer

He says they have to pay attention that as cows swath-graze a high-quality cover crop they might be getting too much of a good thing. “One thing about the swath grazing (windrows), our cows actually got a little too fat. They don’t have to walk around to graze; they can just stand at the windrow and eat. But being fat is better than having them skinny.”

Along with their own 900 head cow-calf herd, the colony custom feeds a lot of cows. “We brought some in last fall that were really skinny,” Hofer says. “They will need a lot of feed to get back in shape,”

It works best for colony management to give cattle access to the whole pivot field rather than trying to limit feed the herd. “Some people use electric fence and only give the cows a certain amount for a week and then move the fence,” Hofer says. “We could have used electric fence, but then it would have been difficult for cattle to have access to water.”

Aaron Hofer, who also works with the beef herd, says when they used to calve earlier in winter it took a lot of stored feed to carry cattle through the winter. “We use to start calving in January and we always needed about 900 big bales for winter feed,” he says. “So we pushed our calving into spring and the cows don’t need as much hay; the pregnant cows are still out grazing the cover crop well into January.”

Trying different combinations

Some annual pasture also includes forage canola/rape varieties. It doesn’t go to seed; it just creates leaves. “Those plants are really high in protein,” says Aaron. “There is also a purple-top turnip in the mix that does create a bulb and the cows like those. Our cows were grazing on one pivot for more than a month and a half and we didn’t have to feed them. With the drought last year we didn’t get enough hay, so it worked out well to have the cows able to graze longer; We didn’t need to start feeding until late January,”

White Lake Colony plans to seed cover crops under more pivots this year so the cows can keep grazing longer through the winter rather than feeding them. “This is so much easier to let them eat the windrows,” says Aaron.

With each passing year as cattle graze under pivots, colony managers expect to see improvements in soil quality. They take soil samples every year. “So far we haven’t noticed much change on those fields, but I think it’s too early,” says Hofer. “After a few years of having cows, there will probably make a difference and improve the soil.”

Along with 900 head of cows of their own, the White Lake Colony also grazes several hundred head of cattle on a custom basis each year. Forages seeded under irrigation in June or July produce excellent feed to extend the grazing season into late fall and early winter.

photo:
Courtesy Aaron Hoffer

The colony has several pivots where they first harvest soft white wheat as a silage crop. Once that’s harvested in July, those fields are seeded with a cover crop of oats plus the Hunter and Goliath turnips.

“The turnips grew well into the fall, handling cold weather down to minus 8 degrees Celsius before it kills them,” says Aaron. “That crop grew about two feet tall, on four pivots. So when the cows came off pasture with their calves, we put 1,800 head on those pivots and they grazed those for more than a month.”

During that period there was a wet snow that flattened the plants to the ground.

“That benefited the soil but made it harder for the cows to graze. We started feeding a bit earlier, but the cover crop did help to extend the grazing season. Looking at fields later where there was still some cover crop residue, there was a lot more moisture in the soil compared to areas where there was no cover crop. We only do cover crops on irrigated acres. We don’t seed the dryland corners of the pivots because it is so dry here and nothing much grows.”

They did try seeding two quarters of dryland to cover crops but the weeds took over.

“If we don’t get any rain, just the weeds thrive,” says Aaron. “Kochia, for instance, thrives in dry conditions and chokes everything else out.”

For the 2022 growing season, the colony plans to adjust the timing of forest crops. The best time to seed cover crops in this area is about the beginning of June. “We’re thinking about putting in just oats for a cover crop after the wheat silage has been harvested,” says Aaron. “The problem we’re having with the cover crop blend is controlling weeds. Once you have the weeds, you always have them. So it might be best to put in something like straight oats that comes in thick and fast and chokes out everything else.”

Aaron says they’ll try more cover crops this season. “It’s just a learning curve on which varieties to seed and how well they do in our area.”

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