Shortly after President Donald Trump signed the 2018 farm bill, which federally legalized industrial hemp production, the first calls to Kansas State Research and Extension scientists started coming in. However, when the Controlled Substances Act of 1970 banned industrial hemp, the research projects into hemp production, products manufacturing, storage and other aspects stopped as well.
Faced with questions about a new crop and potential changes to their production systems, farmers naturally turned to the experts to find the answers.
So the experts got to work.
The first K-State Industrial Hemp Conference, Feb. 4, in Wichita, Kansas, shared the answers from the first trials out of KSRE in 2019. From insect and mite management, to disease prevention, from CBD to fiber production, researchers across the state started to devise projects to find answers to basic questions of this new crop.
Insects and mites
Raymond Cloyd, professor and Extension specialist in horticulture and entomology and plant protection, reminded attendees that controlling insects and mites in their hemp plants requires daily scouting and prevention plans are their best bet for keeping pests out.
“An extensive and aggressive plant protection program early on, in my experience in Colorado, it works,” Cloyd said. Hemp draws an assortment of pests. From sucking pests like cannabis aphids, leafhoppers and hemp rust mites to chewing pests like beet armyworms, grasshoppers and webworms. Even boring pests like corn earworms, which are found in much of neighboring corn fields during the hemp season, feed on hemp in bud, much like the would kernels of corn.
In outdoor hemp fields, green and growing hemp looks like a buffet to pests after corn and soybeans dry down. And while farmers may be used to allowing a threshold of pests in other field crops before they reach for control methods, Cloyd said hemp growers cannot afford the plant stress pests would cause.
“When insects feed on plants they produce secondary compounds that change the composition of the plant,” Cloyd warned. “THC and CBD content may also change in the plant in response.” And if a sample of your field tests above the .03% THC threshold, your field must be destroyed by law and you’re out that production.
Cloyd said Kansas growers can look to their Colorado neighbors for some pest control methods, whether they grow hemp in fields or high tunnels. They include:
Releasing beneficial predators at the outset of the season to take care of pests;
Practice good plant spacing and sanitation in the greenhouse or high tunnel;
Control weeds around fields that serve as hosts for pests, like pigweed;
Consider trap planting, or planting more attractive plants like sunflower around your hemp field to attract pests away from the crop;
Use forceful water sprays on your plants as a physical disruption of the pests.
Cloyd said many of the insects hemp growers will see in their crops they’ve never seen before. “Maybe that’s because they were attracted to another crop in low levels or low densities, but now they see your hemp as a great food source,” he said.
Olathe research
Cary Rivard, Olathe Horticulture Center, shared the results of the field and high tunnel trials from the eastern Kansas site.
“Our question was, ‘How does the production system impact yield, CBD and THC content?’” Rivard told growers. The project looked at using black and white plastic mulches and planting the hemp into a no-till, rolled spring oats cover crop, as well as using high tunnels.
They found:
CBD hemp should be planted in plenty of time so that it has enough vegetative growth by the summer solstice to support the amount of flowering needed.
Plants grown on white plastic mulch did better than those on black plastic mulch.
If planning on growing hemp in a no-till system, using a cover crop, it’s probably better to use a fall-planted cover crop rather than a spring one.
In CBD production, rogue your male hemp plants before they open so that they cannot pollinate female plants.
“CBD hemp is exciting, but there is a ton of potential in this state for fiber and grain hemp,” Rivard said. “We also have feral hemp, so pollination is an issue for hemp growers.” Some counties in other states have addressed this by making it illegal to grow a male hemp plant, to preserve their CBD production. The Olathe site will probably continue its high tunnel research to address that challenge for growers.
Haysville research
Jason Griffin, from the John C. Pair Horticultural Center at Haysville, Kansas, shared some of the findings from the center’s grain and fiber projects. The
The grain project aimed to plant 30 pounds of seed per acre at about a half of an inch deep, Griffin said. They harvested when the plants were at 75% mature grain.
“You can’t wait until the crop is matured completely because it will shatter,” he said. “When industrial hemp seed is ripe, it’ll drop to the ground.”
The fiber only project changed in that the researchers planted double the population per acre because the goal was for straight unbranched stems ideal for fiber, he said.
“If you plant more than a half of an inch deep, it won’t go,” Griffin said. “It’s kind of a wimp, it doesn’t want to be too deep and it needs just enough moisture.”
The center also did variety plots, a simple trial to see how 17 different grain or fiber hemp varieties will perform on the station’s soil and environment.
Future research might include feed trials of CBD and hemp grain to livestock, Griffin said. “KSU Vet Med is feeding some of the seed and tracing the CBD through the animal,” he explained. “It’s still not an approved cattle feed to enter the human food stream. But we want to see what happens when it enters the animal’s system.”
Kansas State’s Industrial Hemp Research project results are now available and can be found online at http://bit.ly/2SXb6bF. The KSU Industrial Hemp Research team is also on Facebook, https://www.facebook.com/kstateindustrialhemp and followers can interact with researchers throughout the growing season with their questions.
Jennifer M. Latzke can be reached at 620-227-1807 or [email protected].
