Variability of cannabinoid yields of fibre hemp cultivars depending on the sowing density and nitrogen fertilisation

The aim of the experiments was to determine the effect of sowing density and nitrogen fertilisation on the cannabidiol (CBD) and Δ9-tetrahydrocannabinol (Δ9-THC) yields in selected cultivars of fibre hemp. A three-factor field experiment was conducted in 2014–2016. Factor A: cultivar (Futura 75, KC Dora and Tygra), factor B: sowing density (60 and 180 seeds/m2) and factor C: nitrogen fertilisation (0, 30, 60 and 90 kg/ha). The CBD yield ranged from 10.52 g/m2 in cv. Tygra to 10.99 g/m2 in cv. KC Dora. Among the examined cultivars, the highest yield of Δ9-THC in cv. KC Dora was observed. Sowing density did not modify the CBD yield, but increasing the density from 60 to 180 seeds/m2 caused an increase in the yield of Δ9-THC in cvs. KC Dora and Tygra. Nitrogen fertilisation significantly influenced the yields of CBD and Δ9-THC. In both cases, yield increased until the rate of 60 kg N/ha.