Canola School: Even crop emergence helps fight herbicide resistance
There are a lot of different strategies farmers can use to delay or manage for herbicide resistant weeds. Some are complex and some are expensive, but sometimes a simple thing like making sure the ground is covered can make a big difference.
RealAgriculture’s Dale Leftwich recently had the chance to speak with Ian Epp, Canola Council agronomy specialist, about some ideas that lead to good emergence and limiting the opportunities for herbicide resistant weeds to get a foothold on your farm. It all begins, he says, with stand establishment.
Often, farmers looking to keep input costs inline start with seed and look for ways to dial back seeding rates. “We think about seed cost being a big issue for growers, or something big on their minds,” Epp says. “We talk about seeding depth a lot (and) seeding speed.” But he also points out that we need to take all the different outcomes into consideration. “When we are targeting a certain amount of plants per square foot we don’t always think about what that means in terms of weed pressure.”
Epp says a consistent plant stand is often as important as overall plant numbers. “It’s not just actual seeding rates or how many plants per square foot we end up with, but also the spatial variation (of those plants). If we have all of these plants, six plants, and they are in a nice tight little row, and there’s a lot of black dirt in between, or a lot of space in between, there’s a lot of opportunity for weeds to germinate, and germinate over a wide period of time.”
Once herbicide resistance is established in a field it increases costs and reduces options tremendously. If you can get your crop to do some of the work, by out-competing weeds, potentially enough to save one pass with the sprayer, it could help in the long run, says Epp. “Every time you’re adding a (herbicide application), especially an in-crop herbicide application, you’re increasing your selection pressure which could lead to some resistance issues down the road.”