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Industrial hemp production in Mo. could become more common

Posted on Friday, August 9, 2019 at 7:09 am

Courtesy Audrain County Extension

The Missouri Department of Agriculture has published the proposed rules in the Missouri Register to implement industrial hemp pilot program. As per department website, the industrial hemp grower and handler applications will be approved and applicants will be notified by October 31, 2019. Missouri farmers are seeking information about the growth and cultivation practices of industrial hemp.

Industrial hemp being grown in Missouri.

Industrial hemp being grown in Missouri.

Industrial hemp are of three different types: fiber, oilseed and dual purpose. Its fiber is used on clothing, shoes, carpets, tarps, rope, nets, paper and building materials. Seed is used as protein flour and seed cake while oil is used on food supplement, soap, beauty products and moisturizer. Hemp’s leaves are also useful for mulch, composting and animal bedding.

Hemp is a short day plant. That means they are planted during early spring, grow during summer and fall and start flowering when the day length is less than 12 hours. Earlier planting is preferred for getting more vegetative growth.

There are different varieties of hemp: tall (6-7 feet tall), medium (4-5 feet tall) and short (3-4 feet tall). Farmers in other states where industrial hemp production has already been, tall and medium varieties are planted as they suppress more weeds than shorter varieties as there are no herbicides labelled for hemp so far.

Hemp is best adapted on a loose, well-drained loam soil with high fertility and organic matter content. Hemp grows good on a soil with pH between 6.0 and 7.0. It does not grow well on wet and heavy clay soil. It is sensitive to soil compaction and crusting and seedlings are prone to damping off.

It can be planted when the soil temperature is around 50˚F and there is no danger of hard freezes. Planting should be done when soil moisture is enough for seed germination. Optimum soil moisture is needed for the first six weeks for seedling establishment.

Optimum seeding depth for industrial hemp is 0.5 to 0.75 inch. Seeding rate depends on variety and production purpose. For oilseed production, 10 plants per square food is optimum. For fiber production, optimum plant density is about 30-35 plants per square foot.

Industrial hemp is normally planted in rows with a standard grain drill. It is typically planted in 6-7 inches rows. There are no herbicides labelled for hemp yet, so it requires mechanical weed control.

Fertilizer requirement is based on soil test value. It requires about same fertility inputs as a high yield crop like corn or wheat. It requires good amount of nitrogen fertilizer. Fertilizers are required more for seed production than fiber. Depending on soil fertility status, it requires 100-130 pounds nitrogen, 45-70 pounds phosphorus and 35-80 pounds potash per acre for a soil with medium levels of phosphorous and potassium.

Hemp is a fast-growing plant that grows almost one foot in 3-4 weeks after planting. By this stage, a good density hemp suppresses all weed growth.

As there is no herbicides, insecticides and fungicides are labelled for use on hemp, crop rotation is the only one options to minimize the risk of pests. Major insect pests of hemp are cutworm, grub, corn borer, armyworm, grasshopper and aphids. This crop is more prone to diseases like bacterial and fungal leaf spots, blight, viruses and Pythium root rot during establishment. Crop rotation with alfalfa, wheat and beans minimize the disease severity on hemp. Rotation with sunflower, canola, edible beans and soybeans increases the risk of while mold disease and insects.

For seed production, hemp is harvested when seeds begin to shatter. By this time, plants may still look green but about 70 percent of the seeds are already riped. Delaying harvesting may cause seed loss in the field from shattering and bird damage.

Hemp grown for fiber production is normally harvested between early bloom to seed set depending on the fiber quality. After cutting hemp, it must undergo a process called retting, which helps to break the bonds between the outer long fibers and inner short fibers. This process takes up to five weeks to complete the field decomposition. Windrows are raked two to three times before harvest to dry and remove leaf materials. After drying, they are baled and stored.