Growth and yield response of fibre hemp cultivars (Cannabis sativa L.) under different N-levels in Eastern Cape Province of South Africa

Abstract

Hemp (Cannabis sativaL.) has been grown in Southern Africa for medicinal purpose for many centuries, and in the past half century as an illegal drug crop marijuana, “dagga”.It was however,noted that hemp has high fibrewhich can be used in formation of particle boards, textile products, paper and clothing. Field experiments were conducted during 2006/2007 and 2007/2008 seasons at Addo ofEastern Cape Province. The objective of the study was to determine the influence of nitrogen fertilizer rates;thus,0,50, 100 and 150 kg ha-1on growthand yieldof fibre hemp cultivars, Kompolti,Felina35 and Novosadska. In 2007/2008,Novosadska was used to replace Felina 35, whose fibre was very short. Trials werelaid out in complete randomised block design with four replications and four nitrogen levelsand two hemp cultivars.The results revealed that there were significantly higherfreshbiomass yields, dry biomass yield, and fibre yield in the fertilized unitsthan in the unfertilized controlunit.The highest plant height, fresh and dry biomass yield were obtained with 100 and 150 kg ha-1of N fertilization were applied at Addo during 2006/2007. Higher nitrogen levels tended to produce higheryieldand qualityin both seasons. Kompolti performed better than Felina 35 and Novosadska. Kompolti had a higher fibre percentageandquantitythanother cultivarsin both seasons.It was therefore concluded that nitrogen application hada positive effect on growth and yieldstudied, and the optimum fertilization rate of nitrogen will be 100 and 150 kg ha-1.