No-till shines on irrigated as well as dryland

Top Crop Manager
November 29, 1999
By Top Crop Manager
Direct seeding has become an accepted practice on dryland, especially in the southern prairies. Now, some farmers are seeding their irrigated land the same way.

Doug Wright switched to zero-till and continuous cropping three years ago, as soon as he found equipment to match what he used in his native Australia.

He couldn't see any reason to treat his irrigated land differently.

The benefits of zero-till don't show as quickly on irrigated land. "Zero-till really shines in a hot, dry spell," says the Nobleford, Alberta farmer. "So, its advantages are less marked in an irrigated crop.

"But, you just have to look at the ground to see what zero-till does for the soil. The land is much more mellow. It's only been three years, but you can see it already. And, I think the impact of the water from the wheel-move irrigation system may compact the soil quite a bit. The ground there is not quite as mellow yet as the dryland."

The growing saline areas that were a major factor in Wright's switch to direct seeding have stopped expanding. Now, the drop in tractor hours seems almost as important.

"When we summerfallowed, we averaged 600 hours a year on the tractor," he says. "Now, it's more like 300 hours a year. That's a big savings in fuel as well as wear and tear on equipment."

Rod Lanier of Lethbridge came to zero-till irrigated land from another direction. His father, Ike, was a pioneer of zero-till and they have no-tilled for almost 20 years, but working with irrigation was a new experience for them. "No-till farming under irrigation is really no different from no-till in a wet year," says Lanier. "We've worked through a few of those lately, so we figured we could manage irrigation."

Lanier has grown irrigated crops for two years. He found no-till has the same benefits under irrigation as it has on dryland. "The evenness of the crop we like on our zero-tilled dryland holds up under irrigation," he says. "We get nice, even germination - just like we enjoy in a wet year on dryland. That holds out through the summer, too. The crop ripens evenly across the field."

The difference between crops on conventionally tilled land and no-till is not as obvious on irrigated land as it is on dryland. "Conventional farmers can get a crop that looks just as even as ours," says Lanier. "It just seems an awful lot of unnecessary work to me."

Lanier tries to keep soil compaction to a minimum on all his fields, but especially those with irrigation. He seeds and combines back and forth, so the trucks can stay in the ditches and off the fields. He chose a low pressure irrigation system to minimize compaction. "I wouldn't have gone to a high pressure system," he says. "They pack the soil too much.

"The low pressure system puts the water on faster and more of it gets to the ground. We're at 80 or 90 percent efficiency and at 35psi, our operating costs are lower than at 65. Also, there's fewer moving parts to wear out, so maintenance should cost less."

Neither farmer has had a problem with too much crop residue on their irrigated land.

Wright leaves his stubble about a foot tall and just uses conventional straw spreaders. He hasn't found straw to be a problem for any of the wide variety of crops he grows - last year he had four varieties of canola, three types of wheat, flax, peas, chickpeas, lentils and barley.

"Any crop I've tried seems to just bounce right out of the ground when it's direct seeded," he says. "In fact, I think the crops are best where the ground is protected with the most straw from the previous crop. The tall stubble protects the ground and shelters the plants when they're little. Baling takes too much away from the land, even with irrigation."

Lanier spreads all his crop residues with a chaff and straw spreader on his combine on dryland. Under irrigation, he will sometimes bale the straw, but he figures he is still gaining organic matter.

"The scientists say that 70 percent of a crop's organic matter is underground," he says. "So, by baling the straw, we're losing 30 percent. If we were to work that straw into the soil, we'd be exposing the soil to the air and losing organic matter. Would we be getting ahead or just staying even? That's a lot of work just to stay even. Zero-till has raised our organic matter levels quite a bit, we'll stick with it."

Lanier and Wright say water infiltration is better on direct seeded land, partly because of higher organic matter levels. "We can put on twice as much water at a time as we could on tilled land," says Lanier. "We have a lot of earthworm activity and old root channels. The soil is really mellow, so the water just soaks right in."

Wright has seen more earthworms, too. "You just dig away the dirt and there are lots of worms," he says. "It's amazing, you can find worms wherever you dig."

Without tillage, some weeds don't germinate. "I'm pleased with my wild oats control, the last few years," says Wright. "I'm still using lots of herbicide, but I think we're having a bit of a win there. Maybe, eventually, wild oats control will get cheaper with less tillage to disturb the weed seeds."

Wright sees only benefits from his switch to zero-till. "There isn't a downside that I can see," he says. "No-till on irrigated land is not that different than on dryland. Why do anything else?"

Even row crop farmers are cutting back on tillage. Bean grower Will Van Roessel of Bow Island, Alberta direct seeded a few acres of narrow row beans this year. "Early in the year, the direct seeded beans didn't look much different from the cultivated," he says. "But, the infiltration was better on the zero-tilled land.

"Our weed control costs were about the same - we used Poast for grassy weeds, but we didn't use Eptam. The plant population was a little lower than we'd like, but, allowing for that, the yield on zero-till was the same as on the worked land."

Herman Kliessen of Chin, Alberta doesn't do any deep tillage before seeding sugar beets. In fall he chops the stubble from a soft wheat crop with a rotary mower, bands in his fertilizer and cultivates with a light S-tine cultivator just to seeding depth. In spring he seeds through the trash layer.

"Our crops have been better than average," he says. "But, if we had to sacrifice a little, I'd do things this way. It would be worth losing a little yield for the peace of mind we get from knowing the land won't blow. The trash layer prevents evaporation, so there's more moisture in the soil in the spring," he says. "Once we start irrigating, water penetration is much better with the trash on top of the soil.

"Every drop of water goes in exactly where it lands. If water moves on the surface of the soil, you're not getting optimum irrigation and you're risking erosion.

"We used to be always on edge, wondering whether a field would blow, especially if we and the neighbours had three or four quarters of black land side-by-side. Now, we don't worry," he says. "It doesn't matter how hard a rain or how big a wind we get, the crop and the land are safe." -30-

Picture: Good openers are essential: This point has seeded 4000 acres for the Laniers.

Picture: Peas, like every crop Doug Wright has tried, germinated well and the 12 inch spacing of his no-till drill allows air circulation to minimize disease.

Picture: Rod Lanier's soil is mellow even at harvest time.

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