Cultivar and management effects on industrial hemp yields in Wisconsin

After decades of heavy regulation, growers across the United States were able to begin growing industrial hemp (Cannabis sativa L.) again in 2014. The 2014 and 2018 Farm Bills made it legal for research and production to resume and removed hemp from the list of controlled substances. Because of the long prohibition of hemp production, many questions surrounding best management practices still exist. In 2019 and 2020, studies were conducted in Arlington and Chippewa Falls, Wisconsin to evaluate the effects of cultivar, seeding rate, and nitrogen rate on hemp yield. Two cultivars (X-59 and CRS-1), seeded at three seeding rates (22, 34, and 45 kg ha(-1)) and three nitrogen rates (0, 67, and 134 kg ha(-1)), were evaluated. At Arlington, nitrogen did not impact fiber yield; however, an interaction among cultivar, seeding rate, and nitrogen rate effected grain yield. At Chippewa Falls, fiber yield increased by 20% when nitrogen rate increased from 0 to 67 or 134 kg N. Similarly, grain yield increased by 52% when the nitrogen rate increased from 0 to 67 or 134 kg ha N. The effect of seeding rate alone was highly variable with no consistent pattern on response variables measured. Therefore, the overall effect of nitrogen rate was more consistent than the effect of seeding rate on response variables measured. Ultimately, management recommendations will be dependent on local conditions; however, hemp does respond to the addition of nitrogen fertilizer.