169 Hemp as a forage crop: Harvest date effects on yield and nutritive value

Abstract

Abstract Hemp (Cannabis sativaL.) has been a valuable species for humans throughout history due to its adaptability and diverse uses. Farmers are interested in hemp as a forage and feedstuff due to its unique nutritional properties and rapid summer production. This study examined yield and nutritive value of three hemp cultivars, ‘Grandi’, ‘Joey’, and ‘EcoFibre’ as potential forage crops when harvested at weekly intervals in Blacksburg, VA, USA, during 2021 and 2022. The greatest biomass and TDN yield across all cultivars were 3.17 Mg ha-1 and 2.08 Mg ha-1, respectively, at 2 mo after establishment in 2021. However, biomass and TDN yield were 1.9 Mg ha-1 and 1.03 Mg ha-1, respectively at 2 mo after establishment in 2022. The nutritive value in hemp plant biomass harvested at different times varied by cultivar and harvest time (P < 0.05). Depending on cultivar and harvest time, hemp plant biomass contained 13 to 32% CP, 22 to 45% NDF, 20 to 38% ADF, 4 to 9% lignin, and 52 to 80% TDN (cultivar × time interaction; P < 0.05). Hemp CP and TDN decreased gradually with maturation while ADF, NDF, and lignin increased; however, this decline with maturity did not appear as severe as occurs with many other forages. These preliminary results suggest that hemp has the potential to be used as a forage crop. More research is needed to address hemp management and utilization, including field establishment and production, harvest timing for optimum tonnage and forage quality, and animal intake and performance studies.