One of the first steps to improving water-holding capacity is understanding what factors control it. Jeff Schoenau, a University of Saskatchewan soil scientist, said two key soil properties play the biggest roles.

The basics

“Water holding capacity of the soil is very much influenced by two things: the organic matter content and the texture, which is the percentage of sand, silt and clay,” said Schoenau. “If a soil has more organic matter and it has more clay, that’s going to increase the available water-holding capacity.”

Clay content, while important, can’t be changed, he explained. A foot of moist clay soil will hold two inches of available water, whereas if it’s a foot of moist sandy soil, it will only hold an inch, or even less if it has a very high sand content.

But water-holding capacity isn’t the whole story. Moisture conservation isn’t just about keeping water in the soil; it’s also about getting water into the soil, or infiltration.

“Things that influence infiltration, like having a surface residue, help promote water entry,” said Schoenau. “We also think about evaporative losses. If we don’t have standing stubble there, that increases the wind speed at the soil surface, and that increases the evaporation.”

He noted that Prairie farmers’ long-standing conservation practices have already helped, contributing to increased water holding capacity, improved infiltration and good soil structure.

“You have a good distribution of pores holding water and some that also hold air to make sure that the soil isn’t flooded or saturated,” he said.

Matching problems to products

While Schoenau focused on the fundamentals, Karthikeyan Narayanan, technical director with Cropland Analytics, zeroed in on how to identify problems and match them with solutions. Cropland Analytics didn’t have a booth at Ag in Motion this year, but we caught up with him at the Annelida Soil Solutions booth, one of the firms his company partners with.

Cropland Analytics operates a fully outfitted, professional lab in Tofield, Alta., testing the biological, physical and chemical aspects of soil.

“The idea behind the lab is to identify the properties of the soil and to understand what’s inhibiting any of those water-holding capacities of the soil as a whole,” said Narayanan. “We do have products, and we do have solutions, but until we identify what the soil needs, it’s going to be very hard to promote one product.”

The business model for Cropland Analytics is based on partnerships with soil amendment companies. His main partners are Annelida and Johnson’s Regenerative.

“They have the solutions that align with what we find in our labs,” said Narayanan. “Ultimately, the farmer needs a solution, and that’s why we align with companies who can provide that solution.”

The partnerships represent a three-way street between Cropland, their partners and the farmer. And Narayanan insists the farmers are the big winners.

“With every test we’ve done and every recommendation we provided, our response rate is over 98 per cent. And that’s on-farm,” he said.

But while Cropland Analytics mainly recommends the products of their partners, an arm of their company is also developing products. Cropland Solutions focuses on developing products while keeping the lab independent to avoid conflicts of interest. The team is actively researching calcium-based products, addressing a common issue with gypsum: limited availability.

Narayanan pointed to one product they’ve designed that he says can boost calcium availability by 400–500 per cent. The product is applied directly in the furrow, targeting only the row rather than trying to amend the entire field. This approach keeps costs low — under $50 per acre. The product aims to improve the rhizosphere while enhancing water infiltration, root growth, phosphorus availability and overall biological activity. He says farmers are seeing immediate benefits, almost as if nitrogen had been added.

Farmers come first

But Narayanan said the main goal is not to sell products. It’s to help farmers. It’s a consultative process more than anything, and if one of his partners doesn’t have a solution, he’ll recommend a third party.

“If I don’t have a solution, but a competitor does, it’s always good if it benefits the farmer,” he said. “As long as they’re doing certain parts of the Annelida, Johnson’s, or Cropland program, it’s fine.”

Narayanan said that many of the water-holding issues he’s called to address fall into the same broad categories identified by Schoenau: soil texture and infiltration.

He noted that sandy soils benefit from organic matter to help retain moisture, while clay soils may hold water but not release it readily to plants. Infiltration problems, he said, can be worsened when fine-textured soils disperse during rainfall, leading to surface sealing, clogged pores and increased runoff.

“So, you have more water runoff from the field than infiltration through the field,” he said.

High tillage or elevated sodium levels can make this worse, though calcium amendments can improve soil structure and help water move into the profile.

While too much tillage harms infiltration, the opposite extreme — continuous no-till — can create its own problem: compaction. Without tillage to break it up, compacted layers can persist and build over time, restricting root growth and water movement. Narayanan said lowering tire pressures by six or seven pounds per square inch can cut that compaction by as much as 15 to 20 per cent.

In his view, farmer awareness and management practices are just as important as any product he or his partners sell.

“There’s no way we can keep amending the soil if the farmer is using bad practices in the field,” he said. “If you want to get out of the hole, you have to stop digging first.”

Cover cropping debate

When asked about other methods for improving water holding capacity, like cover cropping, Narayanan said that while cover cropping will, over time, improve water holding capacity, farmers who are concerned about the water holding capacity of their soils are likely in dry areas — and adding extra mouths to feed when water is scarce isn’t the best idea.

“It’s not growing the cover crop as a problem. It’s about the water,” said Narayanan. “If your water rainfall is low, then what’s going to happen is your cover crop is going to pull that moisture out. So, the following crop won’t have that subsoil moisture.”

Not so fast, said Karlah Rudolph, president of SaskSoil, a farmer-led group promoting soil health and conservation in Saskatchewan.

“I’m in southwestern Saskatchewan, and I do not find that there is an issue with having a cover, even though we’ve been in five years of drought,” she said.

Rudolph farms with her family in Gravelbourg and south of Gull Lake, Sask., combining annual crops with forage and pasture. Her soil science background helped her see the role of cover crops and living roots in protecting soil structure and improving infiltration.

Because of those dry conditions, Rudolph has been closely examining whether cover cropping can work in southwestern Saskatchewan and she planted some crops on her farm to get some answers.

On one of her fields, she’s planted a monocrop system of red lentils.

“There wasn’t a thing growing on it in the spring. It’s as naked as can be,” she said. “I’m observing some visible wind erosion. I’m not very happy about that, but there’s absolutely no competition for the water.”

On another field, she had a hard red spring wheat crop that was underseeded with a low rate of Italian ryegrass and a low rate of sainfoin.

“Sainfoin is a perennial, and it came up in the spring. The Italian ryegrass overwintered, so I had roots at two depths. I had fibrous roots from the Italian ryegrass closer to the surface, and then I had this deep taproot from the sainfoin that was going down at depth.

On the red lentil field, she found that the moisture was closer to the surface, about two inches down. But when she dug where the Italian ryegrass had been planted, the ryegrass had used the water at the surface, and the moisture had moved further down the soil profile. But not by much, she said maybe an inch, and it was much wetter than the moisture level on lentils.

“The snow catch offered by high residue and a high infiltration rate far outweighs the issue of weed competition when it comes to moisture conservation,” she said.

Measuring the moisture

At their Ag in Motion booth, SaskSoil displayed a simple infiltration test kit consisting of a six-inch tube, a bottle of water, a roll of plastic wrap, a wooden block and a stopwatch — it’s exactly the kind of practical, low-cost, MacGyvered innovation you’d expect to see from a farmer-led, DIY group like SaskSoil.

However, just across the lane, Kyle Henderson, business manager for Crop Intelligence, offered a more high-tech option for understanding what’s going on beneath the surface — one perhaps more suitable for those gadget-loving farmers.

“This moisture probe goes one meter into the ground,” said Henderson.

Installed right after seeding, the probe reads initial soil moisture from 100 cm up to 10 cm depth. Combined with rainfall data from a weather station, the system calculates “water-driven yield potential” — how many bushels a crop can produce per inch of available water.

Farmers can also monitor infiltration in real time.

“If you get an inch of rain, does it actually equate to an inch of soil moisture?” Henderson said.

The tool’s data can help identify whether a soil’s holding capacity is limiting yields and guide management decisions throughout the season.

Shared success

From cover-cropping, conservation tillage and residue management to targeted amendments and soil monitoring, improving water-holding capacity is a multi-pronged effort. And for Narayanan, it’s also about the bigger picture.

“At the end of the day, as long as the farmer wins, the entire industry wins,” he said. “We can’t be shortsighted in our approach.”

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Developed by Crop Growth Sciences, PhoSul combines natural rock phosphate with elemental sulphur but also adds amorphous silica.

“It’s a new take on an old idea,” said Darcy Lepine, president of Crop Growth Sciences.

The silica addition is the patented component of the product and plays a key role in freeing up phosphorus for plant use.

Lepine said traditional synthetic fertilizers such as MAP (monoammonium phosphate) rely on water solubility to make phosphorus available. However, that also makes them prone to rapid tie-up in the soil, typically within 30 days.

PhoSul, by contrast, is designed to mimic natural soil processes, relying on microbial activity to create sulfuric acid as it breaks down the sulphur component. This acid releases phosphorus from the rock phosphate.

What makes PhoSul different is the silica, which binds with calcium — a byproduct of the reaction — before it can re-bind with phosphorus. Lepine said this allows up to 90 per cent of the phosphorus to remain plant-available, despite being a non-water soluble product.

Because of its low salt index, PhoSul can be safely placed near seed, even sensitive crops such as canola. Lepine said the product works particularly well in high pH or sodic soils, where synthetic fertilizers often struggle.

The fertilizer also offers environmental benefits. According to Lepine, PhoSul requires five times less carbon dioxide to produce than MAP or DAP. Since it’s not water soluble, it’s less prone to runoff or loss into waterways.

PhoSul can replace all or part of a farmer’s typical phosphorus fertilizer blend and is designed to blend seamlessly with common products such as urea, MAP or MEZ. Lepine emphasized it’s not a silver bullet; rather, it’s a tool to improve soil biology and maintain fertility over time.

PhoSul is now available in Canada, after an initial launch in the U.S. in 2024.

The company has four years of research from Montana State University and about 20,000 acres under use so far this season.

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In mid-July, I received a call from Carl, a grain farmer located near Onoway, Alta., who was concerned about disfigured canola plants in one of his fields.

“It’s not a disaster yet and it seems to be happening in just one field, but I’d like to solve the issue before it gets any worse,” he said.

When I came out to have a look at the field with Carl, I observed the crop was mostly in the early flowering stage with a few straggling plants still bolting. As we walked through the field, I could see the deformed canola Carl was talking about — the plants had parts of their stems pinched off and were kinked over about six inches from the top. I also observed that the symptomatic plants and others around them had leaves that were purpling.

The plants with ribbon stemming symptoms appeared to be scattered randomly throughout the crop. In the worst-hit areas, about one in every 200 plants seemed to be affected, while other areas appeared to be untouched.

After repeated rains in the area that spring and flooding across the field, Carl wondered if what we were seeing could be a stress response to the excess moisture. My thought was although there were plants exhibiting symptoms of moisture stress spread around the field, there was clearly something more at work with those plants with the pinched stems.

Carl and I also discussed the potential for a disease infection that may have occurred in the field due to the perpetually wet conditions throughout the spring and early summer. Although this did seem like a possible explanation, the symptoms didn’t match any of the common diseases of canola in the area.

To rule out a herbicide-related issue, I started asking Carl about his sprayer cleanout processes and the field’s herbicide history that season and in previous years. Between the herbicide history and the seemingly random pattern of affected plants in the field, we agreed this likely wasn’t the case.

There was one important clue, however, that led me to suspect what could be causing the disfigured canola. To be sure, I sent some plant samples off for tissue analysis and when the results came back, it confirmed my diagnosis.

Crop advisor’s solution: Calcium deficiency responsible for disfigured canola

While examining the symptomatic canola plants, I had noted they had purpling leaves, as did most of the other plants in close proximity to them. This was an important clue, as I knew this kind of discolouration can be caused by a nutrient deficiency. Tissue samples sent off to a lab for testing confirmed the plants with ribbon-stemming symptoms were deficient in calcium.

Given that the soils in this area are generally calcium rich, Carl found this somewhat surprising, especially since previous soil samples had confirmed that calcium levels in the field were high. Clearly, however, the crop was not accessing this nutrient properly.

There are a few reasons why this may have been the case. Calcium can be susceptible to leaching and the repeated precipitation in the spring may have caused calcium in the soil to leach out of the root zone and become unavailable for some plants to take up.

In addition, root development and overall plant health were negatively affected by the excess moisture, which also likely contributed to the problem. Shallow, stunted roots or damaged root tips would reduce root exploration for nutrients and the uptake of all nutrients, including calcium. The high relative humidity associated with the rain could have contributed to the reduction of calcium uptake as well due to a reduction in transpiration.

Upon receiving confirmation of the calcium deficiency from the lab, Carl and I discussed the next possible steps to correct the issue. Fortunately for the grower, in the week that had transpired since my initial visit, the field had dried out quite a bit and the conditions had not continued to worsen.

Given the crop staging, a granular fertilizer application was likely to be ineffective, so we discussed the option of using foliar fertilizer product containing calcium instead. Ultimately it was decided that given the overall crop condition and the amount of the field affected by the calcium deficiency, it would not have been economical to make the application.

At harvest time, we felt there was a small yield penalty in the most affected areas of the canola field, but it wasn’t enough to have warranted applying fertilizer. Going forward, Carl plans to focus on managing nutrients proactively as much as he can by monitoring the nutrient levels in the soil and in plant tissues and taking corrective action when necessary.

The experience was a good learning opportunity to remind us all nutrients are important for proper plant development and that there are scenarios where a nutrient like calcium can be abundant in the soil but not necessarily available to the plants at a given point in time.

The post Crop advisor casebook: Why the deformed canola and purpling leaves? appeared first on Grainews.

“As those calcium levels went up — no surprise — our returns came down,” said Greg Frey, location manager for Cavalier Agrow near Meota, Sask. Frey was speaking during Cavalier’s agronomy forum in the Meota area.

In 2017, Cavalier agronomists ran 16 trials in their trading area, which encompasses Medstead, Meota, Spiritwood and Meadow Lake, Saskatchewan. They applied NRG CaB, an ATP Nutrition product, at one litre per acre to canola on the second herbicide pass. NRG CaB is a foliar product that contains eight per cent nitrogen (N), 10 per cent Calcium (Ca), and two per cent boron (B). The product costs $7.70 per acre.

The overall average gain was one bushel per acre. But the average of all locations may not tell the whole story. For example, while Meota saw a 1.2 bushel gain with the calcium treatment, Medstead came in at 3.5 bushels. Medstead soils were also generally lower in calcium, Frey said.

The Spiritwood trials came in with a negative average overall. Frey said they always scratch their heads at negative responses until they can come up with an explanation, other than field variance.

Cavalier Agrow also saw some variation at the sites. For example, seven of the trials were conducted in Meota. Responses ranged from a low of -1.35 bushel per acre to a high of 5.66 bushels per acre. The field with the lowest calcium levels had the biggest yield response to the calcium treatment.

Frey said they see the same type of response with many nutrients, such as copper. Deficient soils will see a return on investment, he said. But not all soils are deficient, he said, and those soils won’t respond. The calcium trials showed that they need to concentrate on areas with deficiencies, he added.

The focus going forward will be putting NRG CaB in the right places, Frey said. They’ll also look at timing. They aimed to apply the product at the three to six leaf stage, but Frey said they were closer to bolting in most trials. By moving the application forward, they’d like to see if they’ll get a more consistent response, said Frey.

Why calcium?

Each year, Cavalier Agrow runs extensive trials to see if products work within the company’s trading area. The company’s trial program, branded as agPROVE, is designed to be professional, reliable, and repeatable, said Frey.

Agronomists start by looking at problems farmers face in their trading area and select products accordingly. They then design a protocol so that they can run each trial the same way at different locations, Frey said. This allows them to compile all the data into one data set, rather than having data from several different trials.

“Sometimes that’s highly successful and other times we run into stumbling blocks,” he said.

After looking at 10,000 different soil test points, agronomists concluded that many soils were calcium deficient.

“Calcium is one of the most important soil nutrients. If it’s not present at a great enough quantity in the soil, trying to balance out some of our other cations like potassium and magnesium can be extremely difficult, if not impossible,” said Frey. It also helps pulses with nodulation, and is a component in cell wall strength. Low calcium is also why many fields in the area have acid soils, he added.

How calcium deficient are the soils in northwest Saskatchewan? There are two ways to measure it. One is to look at base saturation, or what percentage of calcium is found on a soil particle compared to other cations. The optimal range is 65 to 75 per cent calcium, said Frey. From the soils Cavalier Agrow has collected, 20 per cent of soils are at 45 to 55 per cent calcium, and 14 per cent are below 45 per cent.

Another way to measure calcium is to measure the parts per million (ppm) in the soil. Frey said 2,500 ppm or greater is what they’d like to see. Only 18 per cent of the soils they’ve measured hit that optimum level. Another 16 per cent have between 2,000 and 2,500 ppm, leaving them in the marginal area. Another 27 per cent have between 1,500 and 2,000 ppm, and 40 per cent have less than 1,500 ppm of calcium.

Cavalier Agrow has also seen good results with another calcium product, ReLeaf Pulse. ReLeaf Pulse, also sold by ATP Nutrition, is an agPROVE alumnus, having yielded a 3.3 bushel per acre advantage in those trials.

“The bulk of our pea herbicide today goes out with ReLeaf Pulse for that reason,” said Frey.

However, ReLeaf Pulse is a four per cent calcium product. Frey said they wanted to see if the 10 per cent calcium in NRG CaB boosted yields and returns further. So in 2017 they started running trials comparing ReLeaf Pulse to NRG CaB, with no untreated check.

“We had a 2.35 bushel an acre advantage with NRG CaB over ReLeaf Pulse,” said Frey. The average return on investment over ReLeaf Pulse was $14 per acre, once they’d factored in the product cost.

In 2016, they also ran one trial that “sparked their interest” in going forward with NRG CaB, said Frey. That trial was on a field that had been extensively soil tested as part of their iFarm program. The base saturation of calcium, at 52 per cent, put it on the marginal end.

The field also came in at “1,394 parts per million, which put that field in the deficient (zone) for the actual calcium in the field,” said Frey. “And we had a five bushel response. So that’s why we went forward with NRG CaB to this year.”

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Solonetzic soils in the brown or dark brown soil zones of southern Alberta or southern Saskatchewan, that are in native grassland may be best left in their native condition and used for carefully managed livestock grazing. For more information about improving or reclaiming Solonetzic soil, refer to Alberta Agriculture Agdex 518-8 Management of Solonetzic Soils available at Alberta Agriculture’s website.

Sodic soils have limited crop production potential. The relatively high sodium and pH levels restrict the growth and yield potential of most annual crops and even a number of forage crops. Farmers with sodic soils are faced with decisions on how to best manage their land.

Unfortunately, the options are limited.

1. Leave it alone

Option 1: Leave it in its native state.

Sodic soils in native grassland are often best left in their native state and utilized for carefully managed livestock grazing.

2. Work with it

Option 2: Grow sodium-tolerant crops.

Barley is the most tolerant annual crop to sodium, and crops with moderate sodium tolerance are wheat, oat and rye. However, none of these crops will be very productive at SAR levels above eight to 12. The crops most sensitive to sodium toxicity are pulse crops, including pea and lentil; therefore, these crops should not be grown on soils with moderate to higher levels of sodium.

A good option is to establish a sodium-tolerant forage mixture. The most sodium-tolerant forages include various wheat grasses and alfalfa. Fescue grasses have moderate sodium tolerance. Soils that have higher levels of sodium are probably best seeded to a tolerant grass mixture and used for livestock grazing.

3. Reclaim it

Option 3: Reclaim sodic soils.

Reclamation or improvement of sodic soils can be very expensive, and improvement will take time. Reclamation involves careful soil sampling and analysis to determine the severity of the problem and then calculating how much calcium must be added to the soil. Often, several tons of a calcium product must be applied and well incorporated into the soil to modify the sodic condition.

To improve a sodic soil, most of the exchangeable sodium must be removed by leaching it downward, below the root zone. To accomplish this result, the sodium on the soil exchange complex must be replaced by calcium. If free lime (calcium hydroxide) is present in the soil (determined by a soil test), applying elemental sulfur will reduce the soil pH, which will also dissolve the calcium hydroxide that naturally occurs in the soil, to free up the calcium and the calcium will displace the sodium, for gradual soil improvement.

If free lime is not present in the soil, calcium must be added with application of a chemical soil amendment. Soil amendments are calcium-containing materials such as gypsum (calcium sulphate) or calcium chloride. Calcium carbonate is normally not recommended as an amendment due to its lower solubility. Calcium carbonate is ideal for improvement of acidic soils but not for sodic soils.

The calcium amendment is normally broadcast onto the soil surface, followed by thorough incorporation with cultivation. Then, adequate moisture is necessary to dissolve the calcium to initiate the displacement of sodium from the soil exchange complex.

This takes considerable time (many months to years) for natural precipitation to leach the sodium from the root zone. In drier regions, this process could take a number of years and may not be completely successful. However, greater success can result with the application of significant amounts of good quality irrigation water to leach the sodium from the root zone.

Additional organic matter such as livestock manure or green manure will help to improve the physical soil condition (e.g. tilth and water infiltration). However, care must be taken to ensure that any material added to the soil (e.g. manure) does not contain sodium.

The amount of a chemical amendment used to replace the exchangeable sodium in soil will depend on the amount of sodium in the soil, the desired level of soil improvement, the type of amendment used and the volume of soil to be reclaimed. If chemical amendment application is considered, a landowner should work with a qualified agrologist with a specialty in soil science. To learn how to determine gypsum application rates refer to: Alberta Agriculture Agdex 518-20 Management of Sodic Soils.

Once the amendment has been applied, it must be thoroughly mixed into the soil by cultivation. The soil must be very moist for the exchange process to take place. The sodium must then be leached down the soil profile by rainfall or by the application of good quality irrigation water. Short, frequent irrigations will give the best results.

If a sub-surface hard pan layer is preventing internal soil drainage, the soil may have to be deep-ripped to break up the hard pan to allow the sodium to be flushed downward.

The installation of a sub-surface drainage system may be necessary to permanently move the sodium salts from the soil root zone; however, drainage systems are expensive and safe disposal of the high sodium drainage water is essential. Your provincial Environment Department must be contacted prior to installation of a subsurface drainage system to determine the process of approval and licensing of the drainage system.

The amendment of sodic soils can be a long and laborious process and is not always successful or permanent. The occurrence of large rainfall events can cause the water table to rise, moving the sodium salts back into soil root zone, and leading to deflocculation of the surface soil. Therefore, the management of a sodic soil must be considered as an ongoing process.

It is important to note that calcium-containing amendments should never be added to saline or saline-sodic soils because this will only increase the amount of soluble salts in the soil and worsen the salinity problems.

If you are getting technical assistance from a consultant, be sure that person has proper soils expertise to assist you.

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“Water hardness is based on the amount of calcium and magnesium in the water,” Zollinger explains. Hardness is expressed as the amount of calcium in the water added to the amount of magnesium present as calcium carbonate equivalent. “The presence of the other minerals would be additive to the hard water value,” he says. “Hard water may contain mostly calcium, magnesium, iron, and potassium. Soft water contains sodium, similar to how a water softener works in homes.”

Minerals such as calcium, magnesium potassium, iron and sodium contain cations, or positively charged ions, that bind with herbicides, reducing absorption, which results in less activity from the herbicide.

Zollinger delivered a presentation entitled, “Weed Control Issues: How Water Quality Can Affect Herbicide Efficacy” at Manitoba Ag Days, held at Brandon, Man. in January.

During the presentation, Zollinger showed evidence that much of the water in the Prairie provinces is very hard, showing an up to or greater than 250 milligram per litre (ppm) concentration of hardness as calcium carbonate.

Almost all “weak acid” herbicides are antagonized by minerals in hard water, he explained, including glyphosate (Group 9) and Liberty (Group 10), and other “weak acid” herbicides in various chemical groups. Calcium levels of 150 ppm and sodium levels of 300 ppm in spray water are enough to antagonize herbicides.

According to an article on water quality and weed control prepared by Saskatchewan’s Ministry of Agriculture, hard water can also reduce the activity of 2,4-D Amine. If the water is hard enough, this herbicide’s effectiveness is severely reduced.

Additionally, some Saskatchewan groundwater contains relatively high levels of bicarbonate ions. “Bicarbonate content can be a factor affecting the performance of some herbicides, particularly those in the “dim” group such as Achieve (tralkoxydim), Poast Ultra (sethoxydim) and Centurion/Select (clethodim) as well as 2,4-D Amine,” explains the article.

Managing hard water

There are a few steps you can take to mitigate the impact of hard water on herbicide efficacy. One strategy is to apply the maximum rates of herbicides when hard water is an issue. Also, water volume can be reduced to the minimum required for adequate herbicide coverage. This is effective for glyphosate in particular, due to a higher concentration of glyphosate in spray droplets.

Zollinger recommends applying ammonium sulfate (AMS) fertilizer with glyphosate, as it prevents cations in hard water from binding to glyphosate and minimizing its effectiveness.

AMS application rates should vary based on water hardness. Most glyphosate labels recommend an application rate of 8.5 to 17 pounds per 100 gallons, but as little as four pounds per 100 gallons may be enough to overcome most salt antagonism. Zollinger’s guideline for dry application rates is 8.5 pounds per 100 gallons, or 0.8 kilograms per acre. AMS can also be purchased in liquid form for easier application. One guideline for liquid AMS application rates is 1.6 litres per acre. “This will overcome salts in the water and enhance all weak acid herbicides,” Zollinger says.

AMS is not perfect — application requires lots of product, as well as time to let it dissolve in the spray water. In addition, it slows speed of loading and spraying overall, and impurities, as well as low water volume, may plug nozzles. However, Zollinger is convinced that the benefits outweigh the negatives.

“AMS has been the cheapest and most effective method to overcome hard water antagonism of herbicides,” he says. “There are liquid water conditioners on the market that contain low amounts of AMS and other substances, but they are more expensive than AMS and some of them are less effective.”

Zollinger concluded his presentation with a warning: “Know your water quality.”

Growers who suspect they may have water quality issues should send samples for testing. In Saskatchewan, growers can refer to the ALS Environmental Laboratory’s testing services. In Manitoba, Central Testing Laboratory offers water testing packages.

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