SASKATOON – An old pulse crop product will be upgraded this year, said Garry Hnatowich, senior research agronomist with Philom Bios in Saskatoon.
The pea and lentil inoculant Tag Team Next Generation will contain a new strain of nitrogen fixing rhizobia bacteria.
“Across both crops, we’re seeing roughly about a 4.5 percent yield increase over our old strain,” said Hnatowich.
“We’re continually trying to find a better organism to put in the bag. It’s part of an ongoing strain selection program.”
For peas and lentils, the bacteria strain Philom Bios will use is native to prairie soils. Seven years ago, staff travelled Saskatchewan, Alberta and Manitoba, digging volunteer pea plants from fields, or more commonly, native prairie vetch plants.
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Hnatowich said vetch is a legume and the same bacteria that colonizes it, will also fix nitrogen in peas and lentils.
Once staff collected nodules off the plants and sent them to the laboratory, researchers drew out the bacteria and identified the strain.
They then tested each strain to learn which ones produced higher nitrogen fixation levels in peas and lentils in a growth chamber compared to the strain now used in Tag Team.
“The general rule of thumb is that if you can increase nitrogen content in the plant, you’ve increased yield. If we found strains that performed better under controlled conditions, those were the candidates to go out into the field.”
Hnatowich said about 50 strains went through the lab tests. From there, less than 10 qualified for field tests.
“Once we get into the field, we’ve got an idea that they’re higher fixing organisms in a controlled environment. Put them in soil and they may not grow quick enough, they may not compete well with other micro-organisms, so even if they’ve got higher fixation values, they may fall apart in field performance.
“This one didn’t. It lasted through four years of field testing and at that point we had sufficient data to say it’s better than what we had,” he said.
“Ultimately, at the end of the day, we measure it on yield. We will look at nitrogen fixing capabilities, we dig up plants and look at nodules, but it comes down to, are you achieving higher yields with the strain, compared to other strains?”
Hnatowich said new strains are compared to Philom Bios’s products, strains from competitor’s products and bacteria from other countries.
He said the new strain is being tested in other parts of the world to see how effective it could be there, but that may not work out.
“Generally, strains have survived to the conditions you find them in. They’ve acclimatized themselves and are suited to that environment.”
He said the new strain had four years of field trials on peas and lentils over a wide geographic base. He said it may have not been the best performing strain at every site, but it was consistently at or near the top for delivering better yields than other bacteria tested.
In the search for new rhizobia strains, researchers have found it easiest to let the plants isolate the bacteria with trap plots.
“We’ll go into a wheat field, carve out a metre-square area, throw down a handful of pea seeds, stomp it into the ground, then come back a month later and collect the nodules off the plant,” said Hnatowich.
“The plant has selected the rhizobia. That way, you’re getting the most efficient strain for nodulating the plant. That doesn’t guarantee nitrogen fixation. You can have a strain that will form a nodule on a plant but does not fix any nitrogen.”
In the lab, Hnatowich looks at how effective the plant fixes nitrogen. Once in the field, he looks for the infectiveness – can it quickly get to the plant, multiply and form nodules.
“I don’t put a lot of weight on just nodule numbers. I would rather have fewer nodules of a highly effective nitrogen fixing organism than a bunch of nodules that aren’t doing anything. And that can happen,” he said.
The new product uses the same strain for both lentils and peas, but unlike the old strain, Tag Team Next Generation does not work for fababeans. The old strain will still be available.
Hnatowich said the old Tag Team could still be used on peas or lentils, too, but the newer strain should perform better.
“I think this one will last for a while. We haven’t found anything that’s shaken out over the last four or five years that has been as good as this one.”
Hnatowich said another change with the inoculant involves the formulation of the granular product.
“It’s now a peat granule as opposed to gypsum. Last year, the old Tag Team bacteria was on a gypsum granule for our granular inoculants. What that means is that the bag weight is lighter, but it still does the same amount of acres,” he said.
“One of the reasons we switched to peat was we could no longer source sufficient quantities of gypsum, at our specifications, to meet demand.”
