Spud growers let soil lie

Under the Hill Farms is testing minimum-tillage potatoes on a field scale

Potatoes aren’t usually the poster child for minimal tillage.

The reality of the planting, hilling and digging cycle usually means plenty of black dirt, some of it airborne.

But dramatically reducing tillage is exactly what Chad Berry, of Under the Hill Farms near Glenboro, is trying to do.

Berry’s farm, in association with Simplot Canada, is host this year to a demonstration trial hoping to collect data on direct-seeded potatoes, part of Berry’s ongoing efforts to limit soil disturbance and wind erosion on his farm.

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“The main reason is to mitigate blowing,” he said. “We see lots of potato fields in spring. There’s four to five weeks where the fields are black and powdery and, this way, we can leave some stubble standing. It’s not going to be nearly as bad.”

Why it matters: Potatoes have a reputation for high soil disturbance, but Under the Hill Farms near Glenboro is hoping to keep its soil where it is by direct seeding into stubble.

The trial represents an early attempt to scale up minimal-tillage potatoes, something usually limited to the world of market gardens.

This year was Berry’s second attempt at direct seeding. Last year, the farm planted some potatoes on fall rye stubble, but was unable to harvest, thanks to weather challenges.

Chad Berry is already known for his use of soilconservation methods like cover crops. This yearhe’s adding direct-seeded potatoes to the mix.
photo: Alexis Stockford


This year, Berry split one of his potato fields in two. Half of the field was managed conventionally, with spring tillage followed by seeding and hilling, while the second half was direct seeded into canola stubble, using a one-pass hilling system developed in co-operation with genAg and based on technology showcased at the Agritechnica trade fair in Germany.

“The main thing is, if we get the same yield from both sides, we have saved fuel and reduced the erosion,” said Vikram Bisht, a potato plant pathologist with the province and technical adviser for Berry’s project.

Both sides of the field had phosphorus banded into the hill this spring, along with 150 pounds per acre of nitrogen broadcast at seeding. Berry expects to apply another 50 to 60 pounds per acre in season.

The system does not totally eliminate heavy tillage, although Berry says he was able to eliminate two passes prior to seeding this spring.

Both conventional and minimal tillage sections were deep ripped last fall, and fall fertilizer was applied across the field.

This spring, however, the conventionally managed half of the field was worked twice prior to seeding, while Berry used only his one-pass system to seed the other half directly into canola stubble. All potatoes were hilled at the time of planting.

Scott Graham, agronomy raw development manager with Simplot Canada, argued that the system allows producers to reduce spring passes to one, including fertilizer application.

“In the fall, you still have to do that one-pass deep ripping to get your 12 to 15 inches, to break your compaction layers, but this planting system possibly could offer on some sandier soil types the ability to make one pass in the springtime,” he said.

Scott Graham of Simplot addresses the crowd during a field day highlighting direct-seeded potatoes near Glenboro.
photo: Alexis Stockford


Anecdotally, Berry has already noted a difference between conventional and minimally tilled rows.

Berry’s anti-erosion efforts got a test in late May and early June, with weather stations across the province reporting several days with gusts over 70 kilometres an hour. The night before the farm’s field tour June 17, winds clocked at 120 kilometres an hour had ravaged trees and bins near Treherne, less than a half-hour east of the farm.

Canola stubble made a visible difference holding on to soil under those conditions, Berry said, although he added that both conventional and minimally tilled plots had been planted from east to west, and so showed less wind erosion than neighbouring fields with north-south rows.

“It doesn’t really erode far. It just moves the dirt from ‘this’ hill over to ‘this’ next hill, but you still have to go fix it afterwards,” he said.

Equipment

Berry’s project is based around the addition of a one-pass hilling, planting and fertilizer system, modified from a standard Spudnik model.

“The planter itself is just a standard, North American eight-row planter. It leaves 34-inch row spacing,” Mike Wall, genAg’s main contact for Spudnik sales, said.

That spacing alone would have been worth note several years ago, although potato producers in the province have increasingly looked at narrowing rows to increase the number of plants per acre.

The hillers attached to the back of the planter, however, are an innovation out of Europe.

Representatives from genAg and Under the Hill Farms saw the concept after a trip to Agritechnica, the world’s premier trade fair for agricultural technology innovation held in Germany.

“We worked with Spudnik getting those hillers put on a North American machine, so this is kind of a first,” Wall said. “We did some design stuff and got it working. We did a little bit last year but, due to the fall we had, we never were able to harvest it and see the results. But we have a good trial this year and it will be very interesting to see how it comes out.”

Wall estimated that the hilling system adds about 10 per cent to the cost of a new planter. He argued, however, that the efficiencies of the technology would quickly pay that higher price tag.

The design of the hillers is also compatible with most existing Spudnik planters, he noted, although a retrofit would likely come in at about 20 per cent more than ordering a new planter.

“We have a few other farms that are trying different variations of hillers on the back, so we’re going to have a few different ideas to see how each one works,” he said.

Questions and lessons

Dan Sawatzky, manager of the Keystone Potato Producers Association, praised the efforts to limit soil disturbance and said the practice might have merit on lighter soils.

The industry, however, still has some concerns. Sawatzky pointed to questions such as how quickly the soil might warm in the minimally tilled system compared to more intensely worked soil, what impact that might have on emergence and what impact there might be on total yield.

“I think growers always have to weigh off some of the advantages of cost savings and practices on, really, profitability in the end,” he said.

Berry has pointed to fuel and labour savings, thanks to fewer spring passes. At the same time, Berry admitted, switching out his planting equipment was expensive.

Direct-seeded potatoes were slower to emerge, Berry also admitted. Conventionally managed rows broke ground a day and a half to two days earlier than those planted into stubble.

That may have had more to do with water management prior to seeding than an inherent weakness in the practice, though, Berry argued.

“Most of that, I think, was that we put dry soil around the seedbed,” he said. “On the other side of the field, we worked the field up, so it was kind of a moister soil that went around the seed.”

If he were to repeat the experiment, he said, he would have irrigated just after seeding to help close the emergence gap.

It also is not a practice for every field.

A fine, sandier soil has a better chance for success, Berry said, echoing Sawatzky, but a producer with heavier soils might be setting themselves up for frustration and a future of soil lumps.

“You’re going to need a mellow soil type that doesn’t compact or, if it is compacted, you’re going to have to get it ripped in the fall, break the compaction up,” he said. “And you’re going to have to go in and seed at the proper time. You can’t dry the field up with a tillage operation. You have to wait until it’s proper to seed.”

By the numbers

Berry’s field is for demonstration, not a true scientific research trial, Graham stressed, although the team will be collecting data throughout the season.

Three soil probes have been installed on each side of the field, and organizers say they will be collecting data on soil compaction and soil moisture. Satellite imaging will also be tapped to gauge the two management styles, while wildlife cameras have also been installed to compare emergence timing and track the progression of the crop.

Hill size and shape will also be measured periodically, in order to track any differences in hill structure and gauge how much soil is moving off the hills between conventional and minimally tilled systems.

The first such measurements were taken just after planting, and the team says it will repeat those measurements after row closure and again just prior to harvest.

“We’re going to see if the soil tilth is the same,” Bisht said. “We have collected samples from these areas and we will be collecting samples during the season as well and analyze them for the tilth and the soil health. We will not be doing many microbial studies at the moment, but we will see what the soil feels like.”

He does, however, expect soil to improve.

Potato quality, such as the prevalence of scabs, will also go under the microscope, Bisht said.

“I would say, if we had to do it over again, we would do the pre-assessment of the field and expect them to be more similar,” Bisht said. “This year, we have had areas which are not as similar as we would want to compare the two treatments.”

Looking ahead

Berry is currently happy with both sides of his field. Hills look good on both sides, he said and, so far, he has seen no reason to believe there might be a yield disadvantage to the reduced-tillage system.

“I don’t know that there will be a yield advantage either,” he said. “But it’s got a little better water-holding capacity.”

Sawatzky also noted good hills on both sides of Berry’s field, although he added that the industry needs, “a few more years to understand how well it works and under what conditions it works,” he said.

He also credited Simplot Canada’s partnership in the project.

Graham, meanwhile, pointed to the project’s ties to soil sustainability, health and water conservation, things he says are, “on the forefront of Simplot and the potato industry’s mind.”

“Any time we can find a new tool in the tool box and be able to utilize it to be more sustainable and conserve moisture and soil for future generations is important,” he said.

About the author

Reporter

Alexis Stockford

Alexis Stockford is a journalist and photographer with the Manitoba Co-operator. She previously reported with the Morden Times and was news editor of  campus newspaper, The Omega, at Thompson Rivers University in Kamloops, BC. She grew up on a mixed farm near Miami, Man.

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