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The value of micronutrient seed dressings

Micronutrient seed dressings are relatively new in Western Canada. 
Retailers generally don’t claim that these products will increase yield, 
but they may add value for some farmers

Micronutrient seed dressings, already well established in the U.S., are starting to appear on our side of the border. Unlike traditional seed treatments designed to combat plant disease, seed dressings are claimed to boost returns — if not necessarily yields — by promoting better emergence and seedling vigour.

One product has received official CFIA registration. Other products have been reviewed through independent trials in Saskatchewan, but with inconclusive results. Making claims for benefits of micronutrient fertilizer is something of a grey area under Canadian Food Inspection Agency (CFIA) regulations. If the micronutrients are part of a product containing less than 24 per cent nitrogen, phosphorus or potassium, then registration is required.

Only one micronutrient product, Loveland’s Awaken ST, distributed in Canada by UAP, has received CFIA registration. Awaken ST is a seed-applied nutrient, with a micronutrient package including five per cent zinc plus boron, copper, iron, manganese and molybdenum.

“It’s not for the faint of heart to actually pursue a registration for these types of things,” says Eric Gregory, product manager with UAP. Gregory says it took two years of western Canadian trials plus two years of review to register Awaken ST. The product is registered to improve root development, speed emergence, and improve biomass production in cereals.

Trial data showed the seed treated with Awaken ST had an increase of five plants per row foot over untreated seed in 12 separate fields. Though Awaken ST isn’t registered for yield, UAP’s trials did show yield increases. One trial in North Dakota showed a yield bump of nine bushels per acre, though Gregory says that result isn’t typical. Western Canadian trials have shown on average a five per cent yield increase over check, about a 2.5-bushel increase on a 50 bushel wheat crop.

IHARF tests

Two other micronutrient seed dressings have been tested by the Indian Head Agricultural Research Foundation (IHARF) in Saskatchewan. In 2010 and 2011, IHARF evaluated two micronutrient seed dressings — Omex’s Primer Zn on spring wheat and canola, and Omex’s Primer Pulse on lentils and field peas. Crop establishment and yield were evaluated at plots seeded at Canora, Scott, Swift Current and Indian Head. The sites offered different soil conditions, ranging from coarse loam to heavy clays. Both 2010 and 2011 were wetter than normal, and in 2011 seeding was delayed until the end of May in Swift Current and early June in Canora. Temperatures were cooler than normal at most sites in May, and crops at most sites were moisture stressed.

IHARF research manager Chris Holzapfel said there were few differences between treated and untreated plots.

“When we did see an effect, they were pretty few and far between and inconsistent. I would probably say it was almost as common to see a slight negative impact on plant emergence as it was to see a positive impact on plant emergence.”

Holzapfel said Primer Zn did initially benefit spring wheat and canola emergence in Scott in 2011, but overall, yields were similar, regardless of the treatment.

Four composite soil samples were taken at each site each year and analyzed for macro- and micronutrients. Zinc was marginal at all the sites except for Scott. Though none of the sites had a severe micronutrient shortage, Holzapfel doubts that there was enough nutrient in the primers to make a difference in nutrient-deficient soils.

Research concerns

Abdel El Hadrami, Omex’s research and development director, said he has concerns with the IHARF study. He would have liked to see more in-depth soil testing, as Omex uses soil-testing results to suggest products. “If the soil tests show a shortage of manganese, we are not going to recommend the Primer Zn, for example,” Hadrami said.

He said late seeding at some of the sites affected the results, as the products are meant to be used when soil temperatures are below 5 C, when phosphorus and zinc aren’t normally available to the seed. He points to the positive early emergence results in Scott in 2011 as evidence, as seeding conditions were particularly cool and wet at that site.

Hadrami also criticized the data collection and analysis in the study. Plant counts weren’t done in Canora in 2011. In 2010, measurements were done too late to capture emergence at three of the sites. Seeding rates differed between sites, but Hadrami said the different seeding rates weren’t accounted for properly when looking at the emergence rate.

Holzapfel counters that the results were the same, regardless of how the data was presented.

In a written response to the study, Omex said that it did not provide its products to IHARF, and that the study may have used an older version of their products.

Nutritional imbalance

Micronutrient seed dressing promoters are careful not to oversell their products, rather tending to note their benefits for healthy emergence and in turn the health of the crop.

Jarrett Chambers, president of ATP, which is currently submitting a registration claim for its own micronutrient seed treatment, explains that micronutrients correct nutrient imbalances within the seeds rather than soil deficiencies. This nutritional imbalance is independent of environmental conditions, but when the seedling is under stress, there will be a greater response.

Chambers says figuring out which essential nutrients are already being provided by the seed and soil, and which ones the farmer needs to invest in is key.

Chambers has talked to farmers who are thinking about substituting agro-chemicals with seed nutrient dressings to control disease, but says they do not control disease and should never be used in lieu of fungicides.

However, Chambers does see value in seed dressings. “Of all the things I’ve worked on, seed nutrient dressing is the one piece that I do that 90 per cent of the time, the growers says ‘I’m doing that again because I saw a value.’”

Considerations for farmers

Farmers considering micronutrient seed dressings need to think about several things before choosing a product.

Chambers suggests comprehensive seed testing, including a nutrient analysis. Currently there aren’t shared standards for nutrient analysis, he adds. ATP tests seeds for its clients.

Chambers also recommends soil testing, as the effect of nutrient-deficient seed can be compounded by nutrient-deficient soil. Omex’s Hadrami says farmers should consider what was grown in previous years, and what’s going in the ground this year.

UAP’s Gregory says if farmers are combining Awaken ST with a fungicide treatment, they will be doubling the amount of liquid with the seed. He recommends giving the seed time to dry before seeding.

Though it’s inconvenient, Gregory also suggests leaving check strips so farmers know the product is working on their farm.

More research in the works

Holzapfel says IHARF plans to expand research in 2012 to five seed dressing products, once again focusing on emergence and grain yield.

Although Holzapfel says farmers should be cautious about purchasing micronutrient seed dressings, he hesitates to dismiss them entirely.

“There are a lot of different products and nutrients. It does seem to be a legitimate product. It’s a fairly whole new class of fertilizer, but it is a fertilizer just the same. I wouldn’t call it foo-foo dust, but we just haven’t been able to demonstrate a benefit.”

Chambers does think some in the industry are trying to make micronutrients into something they’re not. “We need to calm this down. We need to get this into reality. We need to understand the role of nutrition in crop production, or the role of nutrition in plant disease. It’s part of an integrated program and it’s one important wheel in a very complicated wheel of crop production.” †

About the author

Field Editor

Lisa Guenther

Lisa Guenther is field editor for Grainews based at Livelong, Sask. You can follow her on Twitter @LtoG.

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