K-State Industrial Hemp Dual-Purpose Variety Trials

Hemp is a broad term used to describe the many varieties of Cannabis sativa L. that produce less than 0.3% tetrahydrocannabinol (THC). The crop is globally significant and has recently been approved in the United States.

There are many uses for industrial hemp, and the market for industrial hemp is rapidly growing as more states are legalizing its production. Industrial hemp is marketed for oil, grain, and fiber (Figure 1). Varieties have been selected for improved fiber and grain production that can service these markets. However, little research-based information is available regarding the adaptability or production of these varieties in Kansas. Local testing is particularly important for a short-day crop like hemp because varieties adapted to higher latitudes will likely flower much earlier at lower latitudes and may not have time to generate sufficient growth to support maximum yields. Since 2019 commercially available industrial hemp varieties have been evaluated at two locations in Kansas, K-State’s John C. Pair Horticultural Center near Wichita and the Ashland Bottoms Research Farm near Manhattan.

Figure 1. Two dual-purpose hemp varieties. The variety on the left is more suited for fiber production and the variety on the right is suited for grain production. Photo by Kraig Roozeboom, K-State Research and Extension.

Procedures for these trials, including site characteristics, planting, fertilization, harvest, and variety source and seed characteristics for the trials at both locations are discussed in the following KSRE publications.

2019 K-State Industrial Hemp Dual-Purpose & Fiber Trial:  https://www.northwest.k-state.edu/agronomy/documents/industrial_hemp/PairCenter2019IndustrialHempReport.pdf

2020 K-State Industrial Hemp Dual-Purpose & Fiber Trial: https://newprairiepress.org/kaesrr/vol7/iss9/3/

2021 Kansas State University Industrial Hemp Dual-Purpose Variety and Planting Date Trials: https://newprairiepress.org/kaesrr/vol9/iss3/2/

2022 Kansas State University Industrial Hemp Dual-Purpose Variety Trials: https://newprairiepress.org/kaesrr/vol9/iss3/5/
 

Summary of Results

Wichita Trials

Yield results are available for three of the four years hemp varieties were tested near Wichita (Table 1). Data were collected from all tested varieties in 2019 and 2020, but the entire test was abandoned in 2021 because of variable stands that resulted from heavy rainfall after all three planting attempts. Due to excessive disease pressure (damping off), only four varieties were determined to have plant populations sufficient to be harvested in 2022. The varieties Altair, Henola, Joey, Vega, and X-59 had grain yields in the top group in the one year they were tested at this location. NWG-452, and NWG-2730 had superior stover yields that same year. Helena was in the top group for stover yield in 2019 and 2020 and for grain yield in 2019. In 2022, Orion had the best stand (see full report), but plant height, grain yield, stem weight, and total plant biomass did not differ statistically among the four varieties.
 

Table 1. Stover^† and grain yields for industrial hemp varieties were evaluated at Wichita, KS in 2019, 2020, and 2022.

^† Stover yield was determined by subtracting grain yield from total biomass yield and included flower parts and small stems.

^‡ Values within a column followed by the same letter are not different at α = 0.05. Values in bold are not significantly different from the maximum value within a column.

Manhattan Trials

Yield results from only three of four years are also available for tests in Manhattan (Table 2). The 2019 trial flooded out after both planting attempts. Varieties in the top yield group for either stover or grain, but with only one year of testing included CFX-2, CRS-1, Enecterol, Futura, Rigel, and Orion 33. Varieties in the top yield group in two years for grain included CFX-1, Henola, NWG-2463, and X-59. No variety tested in multiple years was in the top yield group for stover for more than one year.

Table 2. Stover/stalk^† and grain yields for industrial hemp varieties evaluated at Manhattan, KS in 2020 to 2022.

^† In 2020 and 2021 stover yield was determined by subtracting grain yield from total biomass yield and included flower parts and small stems; in 2022 stalk yield was determined directly by weighing stalks after threshing.

^‡ Values within a column followed by the same letter are not different at α = 0.05. Values in bold are not significantly different from the maximum value within a column.

Summary

Hemp varieties clearly differed in their ability to produce stover or stems (important for the fiber market) and grain. Fiber yields ranged from 235 to 4800 pounds/acre and grain yields from 72 to 2380 pounds/acre, depending on location, year, and variety. The small grain yield in Manhattan in 2022 

could be partially explained by the lack of precipitation in much of July and August (aside from a large rainfall event in late July) and by machine threshing in 2022 that likely removed lightweight seed more aggressively than the hand threshing conducted in previous years. Other factors that may have resulted in reduced grain yield in 2022 were significant bird feeding and seed shattering before harvest.

These yield results and the additional information provided in the yearly reports mentioned above provide a starting point for selecting varieties that might have a place in Kansas for fiber and/or grain production.