Power Requirements of Hemp Cutting and Conditioning

Laboratory experiments were conducted on cutting hemp (Cannabis sativa L.) using a sickle knife section and a countershear to determine the mechanical properties of the stems. The results showed that the cutting force and energy were significantly greater at a higher moisture content and specific mass of hemp stem. The average values of the maximum force and the total cutting energy required for cutting a hemp stem were 243 N and 2·1 J, respectively, which were much higher than those reported in the literature for cutting forage crops and maize stalk. Based on the laboratory results, the cutting power requirement in a field situation was estimated using the specific mass of hemp stem and machine feed rate. Power requirement associated with feed rate was investigated in a field experiment of cutting hemp using a reciprocating cutterbar mower operated at three different feed rates. Field conditioning experiments were also conducted to investigate the power requirement for conditioning hemp and a forage crop (alfalfa). The results showed that conditioning hemp required 10–60% more specific energy than conditioning alfalfa.