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Hempicide – Exploring Herbicide Options for Hemp Producers

Farming Smarter, alongside InnoTech Alberta & SARDA Ag Research, are expanding on previous hemp trials with a “Hempicide” project.

The one-year study, sponsored by RDAR, will look at the possibility of new herbicide options for hemp.

This study builds off previous research that showed the effectiveness of potential herbicide options. For our work, we’re taking a shotgun approach, using a handful of options to get a good sense of which cultivars will respond to treatments best.

Melanie Zumbuehl stands above Liam McKay as they lay out the herbicide bottles at our Hempicide trials

“A lot can change throughout the years, so it’s important to repeat these studies every 10 years,” says Mike Gretzinger, Research Coordinator at Farming Smarter. “With new products on the market for pre-emergent weed control and challenges with weed resistance, it’s important to re-evaluate as our practices evolve.”

“I think 10 years ago, there were only a dozen or so varieties in the hemp space. And now, with a lot of the new CBD varieties, that number has jumped up and there’s anywhere between 75 and 100 cultivars,” adds Gretzinger.

At Farming Smarter, we have two research plots for this trial – one focused on volunteer wild oats, the other tackling broadleaf control. As with previous hemp studies done with InnoTech & SARDA, there are locations in the Peace region, in central Alberta, and in southern Alberta.

Historically, hemp has been a small acre crop. However, over the past few years it has grown from below 20,000 acres to more than 80,000 across Canada. Access to herbicide options has always been a challenge for niche crops. We hope to provide these producers with a leg-up in future growing seasons with this study.

The Hempicide Journey

From previous research, hemp’s response to weed pressure seems to be cultivar specific.

Liam McKay sprays herbicide on the volunteer canola Hempicide trial while Melanie Zumbuehl records data.

“When Jan Slaski at InnoTech Alberta first looked at broadleaf weed control options they found that hemp’s herbicide tolerance can be cultivar specific,” Gretzinger adds. “We also noticed in our rotational studies that the year following hemp, many broadleaf products weren’t effective at controlling the hemp volunteers, and therefore could be effective at weed control in hemp crops.”

Broadleaf weeds can be a challenge to control, especially volunteer canola – which can stay in the soil’s seedbank for up to three years.

A challenge for hemp growers, especially fiber producers, is managing weeds like buckwheat flying up the stem of your hemp. Weeds entangling hemp can cause processing delays and issues that cut into your yield. Developing strategies to combat and control these weeds will give hemp producers an advantage, especially in the fiber industry.

Our process for this study involves a few passes with herbicide, followed by ratings check throughout the growing season. We applied pre-seed treatment a few days before seeding, followed by a pass during early emergence before the crop is at risk.

With herbicide applied, we will follow-up with crop checks at rating five to seven, and again at 10 to 14. Following this, we will inspect the crops for injury throughout the rest of the growing season. Before harvest, we will come in and perform standard meter-squared biomass evaluations to see any long-term implications.

Our goal is to gather as much data for the hemp cultivars as possible. While we are testing with regulated, commercially-available herbicides, this study is not intended to promote any of these products.

If you want to see some of our previous studies on hemp, check out these great videos:

Or, read a few of these updates:

Hemp Will Hog Attention As We Study Fiber and Grain

Perfectly Placed Hemp

Hanging Out in the Hemp Field