Effect of Differentiated Nitrogen Nutrition on Aboveground Biomass of Selected Cultivars of Cannabis sativa L. Cultivated Under Central European Conditions

Abstract Hemp (Cannabis sativa L.) is one of the traditional crops currently being newly re-introduced in Slovakia and cultivated for multi-purpose uses, while still there is a lack of crop biomass yield data. The main objective of the paper is to document the yield of aboveground biomass of selected cultivars of hemp ('Bialobrzeskie', 'Felina', 'Santhica', 'Epsilon', and 'Futura'), which were tested in the pilot open-field experiments conducted during 2009 − 2012, immediately after a wave of legislative changes. The trial was agronomically designed including three nitrogen treatments as follows: (i) T1 30 kg N/ha (the full 30 kg/ha in the phenophase BBCH 31), (ii) T2 60 kg N/ha (dividing on 30 + 30 kg/ha in the phenophase BBCH 31 and 51, respectively), and (iii) T3 90 kg N/ha (dividing on 30 + 30 + 30 kg/ha in the phenophase BBCH 31, 51 and 59, respectively); whereas NPK 15-15-15 in the dose of 200 kg/ha was applied before the sowing all across the treatments. The total average dry matter (DM) yield of 9.49 t/ha was achieved, ranging from 2.12 to 16.80 t/ha. DM yield was affected mainly by years (F-ratio 337.40, P-value 0.0000), followed by nitrogen treatment (F-ratio 47.86, P-value 0.0001), then by cultivars (F-ratio 22.37, P-value 0.0019) and finally by replications (F-ratio 0.65, P-value 0.58). However, the need for further studies aimed to quantify more precisely the response of the cultivars to the weather and soil conditions is necessary, especially the cultivars of new and foreign origin.