Researchers in Alberta determine that seed size was slightly bigger and seed weight was up about three percent
Leaving the stubble a little higher when harvesting this year’s cereal crop could make things a lot easier with next year’s peas.
“The idea is you seed your peas into standing wheat stubble, so that the peas go in between the rows of wheat,” said Sheri Strydhorst. “At that point when the peas start to lodge, that wheat stubble keeps them from lying flat on the ground. The stubble acts as a little bit of a fence or prop.”
Strydhorst is an agronomy research specialist with the Alberta Wheat Commission and Alberta Barley. She explained the idea had been explored by Australian researchers, as well as researchers in Western Canada, notably crop adviser and agronomist Steve Larocque in Three Hills, Alta.
What was missing was multi-year data to test how inter-row seeding affected standability and yield in highly productive growing environments. Strydhorst and her colleagues set up small plot trials in black soils with plentiful moisture, where peas typically yield 60 to 90 bushels per acre. These included Alberta sites just north of Edmonton, near Lacombe, and near Falher in the Peace River region.
For the first year, 2015, the researchers seeded AC Foremost wheat. At harvest, they cut the crop at 20 centimetres, at 30 centimetres, and close to the ground to leave virtually no stubble. The next spring, they inter-row seeded with CDC Meadow peas. Row spacing was 20 to 28 centimetres and each plot was five to eight rows wide.
“For us with small plots we could really easily line up that inter-row spacing,” Strydhorst said. “But when you’re dealing with field scale equipment, the producer would need GPS or even better an RTK system to accurately line up their pea seeding in between the wheat stubble.”
While she said most farmers have the necessary technology, the wildcard remains the stubble itself. It must be untilled, and it can’t be badly lodged.
In terms of performance, the peas stretched out a bit more as they reached for the sunlight and grew past the stubble, which Strydhorst said is typical of zero-till systems in general. Seed size was slightly bigger, and seed weight was up about three percent. The peas matured slightly earlier in some plots and yields were unaffected.
The big benefit came at harvesting. During the six site-years of trials, Strydhorst said the researchers experienced extreme to moderate lodging in the peas, but the 30 cm stubble kept them off the ground.
“We did find that inter-row seeding really improved standability when we had that extreme lodging, so it did help out.”
Strydhorst said inter-row seeding fits well into what producers are doing already in these high-productivity areas. That is, farmers often prefer to straight combine, cutting the crop high both to reduce the material going through the machine and to ease management of the residue coming out the back.
“They want to cut as high as possible, but low enough to make sure they’re harvesting all the heads,” she said. “So it is a bit of a variety-by-variety, field-by-field decision.”
Preserving stubble is important, so she recommended avoiding heavy harrowing when managing crop residue. The idea is to keep the stubble standing and well-anchored.
While Strydhorst and her colleagues only looked at wheat, she said similar results would likely be had with other cereals, such as barley and oats. Canola also has high stubble, but the stalks are likely too widely placed to provide effective scaffolding to hold up lodging peas.
She said she hopes the strategy helps farmers who have given up on growing peas because of difficult harvests to reconsider the crop.
“We need this crop in our rotation and if this helps encourage putting more peas in rotation from that system health perspective, I think it’s a great option.”
The research was part of a larger cereals research initiative funded by the Western Grains Research Foundation, Alberta Crop Industry Development Fund, Alberta Innovates and Biosolutions, the Alberta Wheat Commission, Alberta Barley and Alberta Pulse Growers.