The two primary weapons against fusarium — fungicides and resistant varieties — don’t offer the same measure of control as they do for some other important cereal diseases. That’s why Kelly Turkington recommends an integrated approach incorporating best practices that can be used from seeding to post harvest to help farmers get a better grip on fusarium head blight.

Turkington, an Agriculture and Agri-Food Canada plant pathology researcher at Lacombe, Alta., discussed fusarium head blight management with Grainews about after delivering a presentation on the topic at the Manitoba Agronomists’ Conference in December.

Resistant varieties

Turkington notes resistance to Fusarium graminearium, the main species found on Prairie farms, is generally improving, with breeders continuing to make incremental advances in reducing the incidence and severity of fusarium damaged kernels (FDK) and deoxynivalenol (DON) mycotoxins in infected crops.

However, he says growers still need to have realistic expectations around resistant varieties. Wheat rated MR for F. graminearum, for example, won’t provide the same level of control as a variety with an MR rating for stripe rust would, for example.

“Under favourable conditions, like we had in the eastern Prairie region this year, that MR rating reduces the amount of disease,” Turkington says. “You might have five parts per million of DON where you have a susceptible variety, but with your MR variety, you’re still looking at probably two to three parts per million of DON. It doesn’t eliminate it completely, so that’s something to keep in mind.”

Crop rotation

Fusarium can survive on the residue of infected plants, and in very short or continuous rotations of cereal crops, the pathogen can build up and cause serious infestations. Longer rotations of least two years between host crops allows more time for crop stubble to break down and therefore reduces the risk of fusarium infection.

Turkington notes many Prairie producers opt to grow a two-crop rotation, alternating between a cereal crop and canola, which is a non-host crop for fusarium. He says that isn’t ideal for limiting fusarium risk, but he recognizes disease control isn’t the only concern for farmers who have other important rotation considerations, such as commodity prices, reliable markets and management issues for non-host crops such as field peas.

“I always emphasize that I’m recommending a rotation based on my knowledge as a plant pathologist. But at the same time, I understand there are many factors that will influence what crops you decide to plant,” Turkington says.

“Long term, if we can get some better cropping options for growers, we may have a better suite of crops that growers can look at, providing that opportunity to extend the rotational interval between susceptible or host species.”

Turkington says in areas with farmland where F. graminearum is well established, longer rotations may not be enough to prevent a fusarium head blight outbreak in a field if the pathogen is a problem in another one close by.

He notes wind-blown fusarium spores can easily travel from one field to the next, which is why it’s recommended farmers to try to avoid planting small grain cereals right beside cereal or corn fields where F. graminearum levels are known or suspected to be high.

Seeding

Using good-quality certified seed, and seed that has been tested for the fusarium pathogen, is thought to be helpful in fighting fusarium head blight in cereals.

Turkington says for farmers in those parts of the Prairies where fusarium is already well established, the primary concern is how much F. graminearum is present in a seed lot and its likely effect on seed performance.

“It’s very important in that situation to have a seed test done to look at germination and perhaps vigour, and then, of course, the disease load on the seed. That will give you some clues as to whether there are some issues with that seed lot,” he says.

“You have to have pretty high levels of seed infection to start to see a significant drop in germination and ultimately field performance. Typically, once you start getting above about 10 per cent seed infection rate, that’s where a lot of these seed performance issues start to show up.”

Turkington said research has shown fungicidal seed treatments don’t provide complete control of seed to seedling transmission of F. graminearum, but they can give crops a better chance of withstanding the disease and establishing a more uniform stand.

READ MORE: Fungicide timing for wheat leaf disease and FHB

If pathogen levels aren’t too high in seed, he says, good-quality seed treatment that’s applied using good application technology can help ensure rapid uniform seed germination, resulting in uniform seedling emergence and growth and a uniform plant stand.

This in turn will lead to uniform head emergence within the crop and a more uniform target for fusarium fungicide applications during the growing season.

Turkington says farmers wishing to protect cereal crops from fusarium should be mindful of seeding rates as well.

“Seeding rates relate to the uniformity of the target you’re trying to hit with fungicide, which is the head tissue. Lower seeding rates will result in more secondary tiller development and a potentially wider window for potential infection to occur,” Turkington says, acknowledging that challenging weather or soil conditions at seeding may also result in variable emergence and non-uniform crop development.

“It makes it much more difficult to get good coverage of all the head tissue in that field (and) that may increase your risk in in terms of having some issues with fusarium head blight,” he says.

According to Turkington, limiting irrigation at certain times on irrigated fields can also help. Since fusarium head blight thrives in moist conditions he says, reducing or withholding irrigation water for as long as possible after head emergence can help reduce the risk of disease development.

Limiting residue

Because F. graminearum can overwinter in crop stubble, practices that facilitate decomposition of this residue will help remove a potential source of inoculum. This can include using combine straw choppers/spreaders or other implements after harvest to chop up crop residue and distribute it widely over the field.

Turkington notes the smaller residue pieces are, the faster they will decompose. He adds making sure there’s a good spread of material across a field will help prevent those thick swaths of chaff and straw that may contribute to fusarium buildup in subsequent years.

According to Turkington, adjusting equipment so that disease damaged kernels are blown out the back of combines during harvesting can be another effective control measure.

READ MORE: Maps now mark the spots for fusarium risk

U.S. research shows that by removing smaller, lighter weight fusarium-damaged kernels this way, it can lead to grade improvements and also reduce DON levels in infected grain, he says. The practice typically works better for wheat and durum than for barley and oats, because of the type and extent of kernel shrivelling that occurs in these crops.

A potential drawback of this approach is it may increase the fusarium risk to subsequent crops, since it means highly infected material is going back in the field.

Turkington says the decision then for farmers is whether the benefit they hope to gain by having a more marketable grain crop outweighs the disease risk from FDKs, which are very prolific producers of the wind-borne spore stage of F. graminearum.

Turkington notes weed seed destroyers mounted on the back of combines could be another useful tool for limiting the spread of fusarium inoculum since in addition to weed seeds they can crush FDKs.

“I look at the research my colleague Breanne Tidemann had done with harvest weed seed destruction technology and feel it has a potential role to play. Here, you’re basically pulverizing that FDK tissue and facilitating its more rapid decomposition in the field. So there’s a much more rapid disappearance of that as a source of the disease,” he says.

The post More than one way to fight fusarium head blight appeared first on Grainews.

“There’s a lot of different dynamics going on with the water balance in the Prairies,” says Phillip Harder, research director and hydrologist at Croptimistic Technologies.

In addition to summer rains during the growing season adding water to the system, there’s also evaporation from the soil and transpiration from the crops removing it, he explains.

Water then flows through runoff, subsurface flow and groundwater interactions, continuously cycling in and out of the system. And the other big consideration for water management on the Canadian Prairies is, of course, winter.

“Depending on the year, you can have eight calendar months in a row, where you’ve got snow on the ground,” Harder notes. “This is where a lot of our agro-hydrology understandings can fall apart, when we’re looking at other regions that don’t have the same winter processes.”

Water use efficiency

Harder talks a lot about water use efficiency (WUE) — which measures how effectively a crop uses water to produce yield. It’s often expressed as bushels per acre per inch of water.

Though it can vary significantly from crop to crop, it tends to remain fairly stable within a given crop type, meaning there’s little that a farmer can do to improve on that ratio.

The important thing to remember, though, is that water doesn’t have to come from precipitation during the growing season. It can also come from spring snowmelt or groundwater. So, a field that saw very little rain could still produce a good crop if there is sufficient moisture in the ground from other sources — and growers do have some limited control over that.

“We need to understand our productivity in our particular year. We need to understand our multi-year soil moisture legacies, not just the growing season rainfall,” Harder says. “It’s a complex story, but we have tools to manage these things.”

Holding on to your snow

One simple and effective tool growers can use is retaining winter snowpack with crop stubble. 

“If you leave taller standing stubble in the field, you increase the aerodynamic roughness, and it basically will trap your snow where it is,” Harder explains. That’s fairly intuitive, but what might be less obvious are the implications stubble management has on sublimation.

“In places like Regina, with wide-open plains, you can have a fair bit of snow, but you also have those really intense winds,” he said. “When snow is blowing through a field, you’re losing a lot of snow straight back into the atmosphere.”

In a fallow field with no resistance, only about 23 per cent of the snow remains on the landscape, Harder says. If that same field had stubble, it could hold onto roughly 48 per cent of that snow.

In terms of water retention, Harder notes if you increase your stubble height from zero to 50 cm, on average, there would be 50 mm of water available for the crops.

“In a water-limited environment, an extra inch or two of moisture can make a difference,” he notes. However, Harder points out the impact would be less in areas with more shelter, where blowing snow is less of a concern.

Keeping water in the landscape

Another strategy farmers can employ to help them hold on to moisture is by maintaining the water already in the landscape.

“This is where your soil residues come into play,” Harder says. “If you’re able to increase the residue retention on your surface, you will basically disconnect the vapour pressure gradient between your soil and the atmosphere, and you will suppress soil evaporation.”

In other words, if you keep it covered, the water doesn’t evaporate nearly as much. The challenge is that the hydrologic implications of residue management are inconsistent. For example, tillage of a dry field doesn’t change anything, but tillage of a wet field does.

“You have to be aware what the starting point of your soil moisture is,” Harder says. “There’s a general rule of thumb that for every 10 per cent increase in cover, you might be able to reduce your soil evaporation by five per cent.”

Those numbers might sound small, but as Harder points out, they all add up.

Leveraging topography to your advantage

The topography of the land is another area producers will often look at as the hand they’ve been dealt — but there are ways to make the topography work for them.

The key, Harder says, is slowing down the water as much as possible and having it infiltrate the soil.

There are limitations. Hilltops lack the water-holding capacity of low-lying areas. Farmers could dig ditches or level hilltops, but there are easier, passive methods that require far less diesel. For example, Harder highlights the role of crop residue.

“A thick crop residue layer will really slow down water movement, and everything you can do to slow down water movement gives it the opportunity to infiltrate,” he says, noting that refraining from tillage is the obvious first step a grower can take.

“The reason we have saturated depressions comes down to that snowmelt infiltration period, so more residue slows things down, and that lets it infiltrate in place,” he added. “That’s an easy one.”

Harder said farmers could also try to leave taller stubble on hilltops and shorter stubble in the depressions — although that could be a problem because dry hilltops might not have the biomass to support that strategy.

Another way to take advantage of the landscape is variable seeding rates based on topography.

“Maybe you want to scale back your seeding rates on your hilltops, so there’s less water demand, and amp up seeding rates in depressions,” Harder offers. “It really depends on the crop type.”

Similarly, intercropping can be used. For example, a producer could plant a water-loving crop such as canola in the depressions, where it can soak up excess water, while planting something like lentils on the hilltop.

“There’s different strategies out there, but at the end of the day, there’s a lot you can do besides ditching,” Harder says.

The post Retain your rain appeared first on Grainews.

His field observations in the 2021 growing season, followed by on-farm research trials through 2022 and 2023, produced data to support a recommendation to leave taller crop stubble. Even a couple of extra inches will trap more snow, which will increase soil moisture and lead to higher yields.

“The research showed that every extra inch of stubble height can serve to trap more snow and lead to more moisture for the crop the following year,” says Palmier, owner of Max Ag Consulting at Plenty, about 70 kilometres northeast of Kindersley. “Our 2023 research showed that every extra one inch of crop stubble can increase canola yield by 1.1 bushels per acre.”

He notes there are several variables — there must be snow to start with — but the field trial showed that grain stubble left even two inches taller can result in a canola crop producing two more bushels of oilseed per acre. At about $13 per bushel, that’s a value of about $26 more per acre. The only management change needed is to raise the combine header two inches higher.

Palmier’s look into the value of stubble height began with a couple of harvest situations in fall 2021, which led to the on-farm research trial in 2022. The growing season was dry in 2021, but in one area there was moisture before harvest that caused a lot of volunteer regrowth in one canola field. It was difficult to harvest the standing crop, resulting in a lot of tall stubble.

In another situation, again due to the dry growing season, a producer left part of his canola crop unharvested because of poor yields. Both cases left tall or fairly heavy standing crop residue that trapped and held snow.

“In the early part of harvest in 2022, the yield data showed that something was affecting yield on these fields that had standing stubble and unharvested crop from the previous year,” says Palmier. “Were higher yields in these areas due to taller stubble trapping more snow and ultimately more moisture for the subsequent crop?”

Working with the producer, he launched the on-farm research trial that fall to find out.

Good support from client

Palmier was working with a client who was anxious to learn more about the value of crop height and trapping snow to improve yield. That producer had already invested in two types of harvest systems — two combines equipped with stripper headers and one with a conventional header.

The plan was to establish field scale plots of about 20 acres with varying stubble height in a field of durum wheat. Some plots were harvested with the stripper header, leaving stubble as tall as possible, and other plots were harvested with a combine equipped with a conventional header.

“It’s common for many producers to leave stubble about eight to 10 inches tall,” says Palmier. “The producer I was working with didn’t want to cut the durum crop that short. He was pretty confident that taller stubble could trap more snow, so he wanted to capture as much moisture as possible and still provide a comparison.

“So, the stubble with the conventional combine was cut a bit taller than average but not as tall as the stripper header stubble.”

Palmier says durum stubble height was 18 to 20 inches in stripper header plots and 12 to 14 inches in the conventional header plots. The producer was already using variable rate technology in his fields.

A VR mapping system had identified 10 different production zones on the field and research plots were established in several of those zones. The producer was already using Bayer’s Climate Fieldview technology with GPS tracking, so it was used to measure and mark 20-acre plots for the project.

The durum field was harvested in fall 2022 with 20-acre plots all in the same field. Some were harvested with the stripper header and others with a conventional header. All that was needed was snow, and it did come.

“There was a fairly early snowfall in the fall of 2022, which was captured in the stubble,” says Palmier. “And prevailing winds are important as well. Typically, in this area, winds are from the west, but in the winter of 2022/23, we also had winds from the east. As winds change direction, they help to carry more snow into the stubble.”

He says it is important to note that the 2022 growing season and harvest conditions were extremely dry, so there was no immediate topsoil moisture heading into winter. Without moisture, the soil didn’t freeze so it was receptive when the snow did melt. There was no run-off.

Measuring snow density

The field was left for the fall and winter until February 2023, when Palmier measured the amount of snow and moisture held in the various stubble heights.

“For the snow survey, we collected 10 snow samples from both conventional and stripper stubbles to weigh for snow density,” he says. “We also measured 30 points in both stubbles for snow heights to estimate the average snow height in both treatments. By combining both these measurements, we could then understand what our average snow water equivalent was in the two treatments.”

Palmier noted snow density in the stubble varied between the two harvest treatments. The snow in the stripper header stubble had about 25 per cent moisture, while the conventional stubble had about 27 per cent moisture. He suspects the difference in density was due to the conventional stubble moving more with the wind, allowing the snow to settle, while the stripper header stubble was more rigid.

“Even though the snow in the conventional stubble had more density, there was less of it,” says Palmier. “Whereas the snow caught in the stripper stubble was less dense, but there was more of it due to increased stubble height. Ultimately the stripper header stubble held 20 mm more moisture than the conventional stubble.”

After the snow survey, the field was left until seeding. As spring approached, snow in the stripper header stubble melted sooner than that in the conventional stubble, likely because there was more exposed stubble on the stripper header plots to attract solar energy. Because the ground wasn’t frozen, any moisture went straight into the soil.

Soil moisture probes are key

The final bit of important technology needed to monitor the research project was an on-farm weather station outfitted with soil moisture probes. The project used a Crop Intelligence RealmFive weather station that wirelessly connected to two John Deere moisture probes.

“We set the weather station up at the edge of the field and placed the two soil moisture probes in the same field. One was placed in the stripper stubble plots and one in conventional stubble plots,” says Palmier.

The field was seeded to canola with a disc drill on May 16, and the soil moisture probes were installed May 21. The probes were connected wirelessly to the RealmFive weather station by a flex station, which pulls data from the probe. The station contains a modem and SIM card, where it can upload data to the cloud. It is stored and processed on Crop Intelligence’s platform.

The John Deere soil moisture probes have six sensor points at varying depths along the 100 cm length of the probe. Palmier used a three-inch diameter handheld auger to create a hole the right depth for the probe. To ensure proper soil contact, he first made a slurry of soil and water to fill the hole and then pushed the probe into the slurry.

Once in soil, the probes’ sensors provide soil moisture readings at intervals from 10 cm to 20 cm, 30 cm, 50 cm, 70 cm and 100 cm (from four inches to 40 inches). He says it is important to know the soil type to understand its moisture-holding capacity. Clay soil, for example, will have a plant wilting point with a reading of 20 per cent soil moisture and a maximum moisture-holding capacity of 50 per cent moisture. Sandy loam, on the other hand, will have a wilting point of eight per cent moisture and a maximum holding capacity of 32 per cent moisture.

“It is important to know soil texture,” says Palmier. “The probe will only tell you how much moisture is present, so if it says 32 per cent and you have sandy loam soil, you know the soil is at moisture-holding capacity, but if it is 32 per cent and your soil is more clay, you know you are a long way from moisture-holding capacity. “

For the 2023 growing season, Palmier measured about 20 mm (roughly 0.8 inch) more plant available moisture at the start of the year on the stripper header strips than on the conventional header strips.

The rest of the growing season was not particularly kind to the crop. From May until mid-August, there were just over 82 mm (three inches) of rainfall. The biggest rainfall after June 3 amounted to 11 mm, or less than half an inch. Overall, it was about 39 per cent of the average growing season rainfall. And on top of dry conditions, there were plenty of hot days. Between June 5 and Aug. 15, 22 days were 30 C or hotter.

On the field with alternating strips of crop grown on tall and shorter stubble, canola plants showed a difference in growth pattern. Palmier says the roots on two treatments reached the 10- and 20-cm depths at about the same time. After that, the crop seeded on the stripper header stubble reached 30 cm two days earlier, and 50 and 70 cm depths six days earlier than the short stubble crop.

“That tells me the crop on stripper header stubble appeared to be more vigorous. It had moisture but also the taller stubble most likely helped to reduce abiotic stress factors by providing more shade to plants and protecting plants from the wind and other stressors,” says Palmier.

He also found that the crop on the stripper header stubble started the year with more moisture and ended the growing season with less soil moisture than the shorter stubble crop. Again, it was an indicator of more robust plants that developed more roots and used more moisture.

Overall, the crop with taller stubble yielded six to eight more bushels per acre than crop grown on shorter stubble.

Palmier says not every farm can handle stubble that’s 15 to 20 inches tall, because not every seeding system can work through that much standing crop residue.

“But the point is, if a producer can leave stubble even two or three inches taller — go from eight to 10 or from 10 to 12 inches — it can make a difference in how much snow is trapped and how much moisture is available to the crop.”

“There are only so many things we can control, but we can set things up to take advantage of snow and moisture if or when it does come,” says Palmier. “And particularly during extremely dry conditions, every little bit helps. Small changes in management can make a difference.”

Palmier planned to monitor fields with crops seeded into different stubble heights during the 2024 growing season as well.

The post Research confirms value of taller crop stubble appeared first on Grainews.

That was a late takeaway from an ag tire clinic for farmers at Melfort, Sask. in July, hosted by staff from retailer Kal Tire and manufacturer Firestone Ag. It’s not that ag tires are in any way weaker today, but rather that crop stalks and stubble — be they canola, corn or others — are definitely stronger.

Consider the yields you were getting years ago, says Dusty Hininger, a Texas-based sales training manager with the Firestone Ag division of Bridgestone Americas.

“What is it now — is it the same stalk? No. They’ve genetically modified that stalk to hold (the plant) up, make it stronger and stronger. Because why? They’re getting more bushels,” he told the Melfort audience.

“Are we done (increasing yield)? What are your bushels now, is it 60-80? You think they’re done? Twenty years, you’re going to have 120. Is that the same stalk? No. Because stalks are getting harder and harder.”

And improved genetics are only part of the issue, the companies warn. Not only do stronger stalks decay more slowly, but your improved farming practices “are resulting in higher population rates with stouter, healthier stalks.”

“This is going to get worse, I guarantee you,” Hininger says. “All tires do not like stubble.”

Of course, the peak period for risk to your tires is right after the crop comes off the field — but stubble can still cause problems for your tires the following spring, especially when weather conditions favour those standing stalks.

For example: in a relatively dry off-season, not only will crop residues go through less decay, but the soil will also hold those residues more firmly in place when your tires pass over them in the spring.

A relatively dry growing season, on the other hand, would produce smaller-diameter stalks that are less likely to retain that stiffness for long.

How you cut those crops will also be a factor, the companies add.

For example, if your pass in the spring is at an angle to your pass from the previous fall, your tires will be more exposed to upright stubble.

Stalks that were cut at a higher angle will more easily puncture a tire. Also, lower cutting height raises the chance of a tire running over, rather than knocking down, an upright stalk. Taller tires are also less able to knock over those stalks, the companies say.

Some tire arrangements are also more at risk of damage than others, Firestone says. The more susceptible fitments include the steer tires on combines with front duals; front single tires on combines; mechanical front-wheel drive (MFWD) and four-wheel drive front tires; and MFWD rear tires that are wider than the front tires.

What’s more, if you’re going to get a puncture from stubble in your tractor or combine tire, those most typically happen during the tire’s first season in service — particularly if it’s from a more recent production run, Firestone says.

That’s not to say the newer tires are in any way inferior. Rather, it’s just that tires are at their most susceptible when the rubber hasn’t yet had a chance to harden naturally over time.

For its part, that’s why Firestone’s got a stubble damage policy covering certain of its ag tires against excessive wear through abrasion, within their first three years of service. The coverage is gradually reduced year over year.

Punches and scrapes

To be sure, a puncture is going to be the more pressing problem, because it risks piercing a tire’s inner liner, causing leaks.

Even if a strong standing stalk doesn’t cause a puncture, exposure to tough crop stubble over time can gradually wear at a tire tread and/or sidewall. The abrasion you might see in those cases shouldn’t punch through to the tire’s inner liner; nor would it cause air loss “except in very advanced cases,” Firestone Ag says.

The damage caused by that kind of gradual abrasion can be a bad look, though, when it comes time to sell or trade in your tractor, Firestone adds.

But if the cosmetics of an affected tire don’t bother you, the tire will still be serviceable — except, of course, if the abrasion is serious enough to expose cords.

Mechanical solutions

The most effective way to prevent abrasion or punctures from stubble is to knock down the stalks before your tires reach them. To do that, you’d need to make or buy a combine header attachment such as a stalk roller.

Apart from preventing damage to the tires coming right up behind the header, these attachments should also crimp the stalks. Not only will that speed up the decay of the stalks, but it will also reduce soil erosion by helping to keep the crop residue from blowing off the field.

Several companies make and sell such header attachments. In Hininger’s presentation, examples included PolyTech’s Stubble Stoppers, Yetter’s 5000 Stalk Devastator and May Wes’s G4 Stalk Stomper, among others.

“All you have to do is get that stalk (bent) about 75 per cent over,” Hininger says.

If you go for that kind of an attachment, though, he cautions you to make very sure it will apply enough down-force to bend the stubble. He tells the story of one field in Texas where the stalks, once pushed over, popped back up and still had enough strength to punch into a tire.

Past that, Firestone also recommends that you cut crops as high as possible, so your tires stand a better chance of knocking down stalks rather than hitting the points head-on.

In row crops, the company says, you may also want to try to drive between the rows to reduce your tires’ direct exposure to stalks and stubble.

Firestone also recommends keeping your tires appropriately inflated “at all times.” The tread and sidewalls of an under-inflated tire will be more exposed to stubble. An over-inflated tire, meanwhile, is more likely to get a puncture.

The post Expect stalks and stubble to become more stabby appeared first on Grainews.

That’s not just wishful thinking, says Saskatchewan crop consultant Mike Palmier, owner of Max Ag Consulting at Plenty, about 70 km northeast of Kindersley. Along with some general observations, he’s conducted field-scale research trials that show leaving stubble taller makes a difference.

On one research project, monitored over the fall of 2022 and through the 2023 growing and harvest seasons, crop grown on areas with taller stubble produced six to eight bushels more canola per acre compared to adjoining strips of field with shorter stubble. The taller stubble trapped more snow, which helped carry the crop through a dry growing season.

“If we get a good heavy snowfall over winter that packs into those stubble rows, I figure that each inch of stubble height will produce about 1.1 bushels of canola,” says Palmier, looking at research conducted last year. “So, for example, if you leave stubble two inches taller than you normally do, that moisture could produce two more bushels of canola and if the market value is around $18 per bushel, you’re looking at close to $40 more yield per acre.”

READ MORE: Drought preparedness through soil and crop management

Palmier admits conditions will vary, so not everyone will see the same results, but the key message for producers is to think about leaving crop stubble as tall as possible, and if the snow comes there is at least a good chance it will translate into more moisture and higher yields.

“In many respects stubble height may seem like a small thing, but when you have extremely dry growing conditions, those little things can make a difference,” he says. “We can’t control the weather, but perhaps we can do a better job of capturing and making use of the moisture that does come.”

Field observations

Palmier, who launched Max Ag in 2019 and, now with a staff of six, works with clients across central Saskatchewan, says field observations in 2021 and 2022 that prompted him to launch the field-scale research trials that continue in 2024.

“We’ve had three extremely dry growing seasons in central Saskatchewan as well as other parts of the Prairies,” he says. The summer of 2021 was extremely dry, for example, but then there was some rainfall in September that caused a problem with regrowth.

“There were standing canola crops and then the fall moisture caused seeds to germinate, so we also had a lot of regrowth. It made for a challenge at harvest, with more crop stubble left behind.”

That fall there was a heavy snowfall, and the following growing season farmers were seeing higher yields in the fall of 2022 on crops grown on fields where stubble had been left thicker and taller. Taller stubble, in particular, appeared to have trapped more snow, resulting in more moisture, which led to higher yields.

In another situation, Palmier points to a farmer with a poor canola stand due to the drought in 2021. With his combine equipped with a stripper header, he harvested a few test strips and was only getting three or four bushels per acre, so decided to leave the rest of the field unharvested. He owned a disc drill and knew he’d be able to seed through that unharvested crop the following year. In November 2021 came heavy snowfall, which was caught by that standing stubble.

“The spring of 2022 that field was seeded to durum and there was a visual difference in crop growth, between the strips that had been combined and the area of the field that had taller crop residue,” Palmier says. “You could easily see it in satellite imagery throughout the whole growing season. On the strips of field where the farmer had made a few passes with the combine, almost nothing was growing, but on that area of the field where the canola crop had been left unharvested, it trapped more snow, the moisture went straight into the ground and it produced a decent durum crop.”

Realizing something was happening because of this taller stubble, Palmier set up an on-farm research trial with that same farmer for the fall of 2022. They chose one canola field where part of the field was harvested with the combine with a stripper header, leaving stubble as tall as possible, even up to 18 and 24 inches in height. While alternate strips for the crop were harvested with a combine equipped with a conventional header leaving stubble at eight to 10 inches in height. Weather stations with moisture sensors were set up on each treatment, with the Crop Intelligence app used to interpret the data. In the fall of 2022 there was good snowfall again and also variable winds, which helped move the snow around and into the stubble.

The 2023 experience

“For the 2023 growing season we measured about 20 mm (roughly 0.75 inch) more plant available moisture at the start of the year on the stripper header strips than on the conventional header strips,” Palmier says.

The rest of the growing season was not particularly kind to the crop. From May until mid-August there was only a little over 82 mm, or three inches, of rainfall, with the biggest rainfall after June 3 amounting to 11 mm, or less than half an inch.

Overall, it was about 39 per cent of the average growing season rainfall — and on top of dry conditions there were plenty of hot days. Between June 5 and Aug. 15 there were 22 days in which temperatures reached above 30 C.

On this field with alternating strips of crop grown on tall and shorter stubble, canola plants showed a difference in growth pattern. The weather station had soil moisture probes at various levels or intervals which included 10, 20, 30, 50, 70 and 100 cm in depth — that is, four inches down to about 40 inches.

Palmier says the crop roots on the two treatments reached the 10- and 20-cm depths at about the same time; however, after that, the crop seeded on the stripper header stubble reached 30 cm two days earlier, and 50- and 70-cm depths six days earlier than the short stubble crop.

“That tells me the crop on stripper header stubble appeared to be more vigorous, it had moisture but also the taller stubble most likely helped to reduce abiotic stress factors by providing more shade to plants and protecting plants from the wind, and other stressors,” Palmier says.

He also found the crop on the stripper header stubble started the year with more moisture and ended the growing season with less soil moisture than the shorter-stubble crop. Again, it was an indicator of more robust plants, developing more roots and using more moisture.

Overall, in comparing yield between the two harvest treatments, the crop with the taller stubble yielded six to eight more bushels per acre than crop grown on the shorter stubble.

Palmier says not every farm can handle stubble that’s 15 to 20 inches tall, because not every seeding system can work through that much standing crop residue.

“But the point is, if a producer can leave stubble even two or three inches taller — go from eight to 10 or from 10 to 12 inches — it can make a difference in how much snow is trapped and how much moisture is available to the crop,” he says.

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He points out there are several factors that will affect how much snow is trapped and how much moisture infiltrates into the soil:

• Leave stubble as tall as possible to accommodate your seeding system.
• Do a good job of straw spreading and residue management.
• If there is fall moisture and the ground freezes, there is increased risk of moisture runoff when the snow melts. If the soil doesn’t freeze, moisture will most likely infiltrate into the soil.
• Of course you need snowfall, but wind is important too. If winds are blowing from different directions during snowstorms, that will help to fill in both sides of the stubble rows.
• Plan to have a field harvested with tall stubble next to a pulse crop field. Pulse crops, such as peas and lentils, usually don’t have much standing residue after harvest, so when there is a snowstorm, snow from the lentil field could blow into the adjoining field with taller stubble.

“There are only so many things we can control, but we can set things up to take advantage of snow and moisture if or when it does come,” Palmier says. “And particularly during extremely dry conditions every little bit helps — small changes in management can make a difference.”

Palmier will be monitoring fields with crops seeded into different stubble heights during the 2024 growing season as well.

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