Pulse crops tend to not be as competitive as other crops, such as cereals, which is why we refer to it as the critical weed free period early in the growing season.
By definition, these are growth stages in the crop that must be kept weed free to prevent yield loss.
In this Pulse School episode, we talk to Neil Harker, weed research scientist at Agriculture and Agri-Food Canada’s Lacombe Research Centre, about this period of growth.
Harker suggests this can be anywhere from the two leaf to six leaf stage, varying with what pulse crop you are growing and conditions.
“We typically think of yield being affected by crops that are competing for light, nutrients, or moisture. And I think looking at it over the years it’s mostly light, especially early on, where their generally is good moisture and nutrients,” he explains. “Because we start to lose yield in pulse crops as early as the two to three leaf stages. There just doesn’t seem to be much competition at that point for nutrients and water.”
Harker notes the critical weed free period generally starts earlier than you’d think — before the crop appears to be competing against weeds. For pulses, the yield impact can be more severe than other crops because they tend close their canopy later than wheat, barley, or canola.
Read more on the critical weed free period in pulse crops in this SaskPulse update.