Effect of Nitrogen Fertilization on Growth and Yield of Industrial Hemp (Cannabis sativa L.)

Abstract

Fibre hemp is grown for a multitude of end products derived from its cannabinoids, seed, fibre and wooden core. A key factor that influences the quantity and quality of the production of hemp is nitrogen fertilization. The aim of this study was to determine the response of five well-adapted industrial hemp cultivars to different nitrogen fertilization rates during the 2016 growing season. The experiment was laid out in a split-plot design with two replicates, five main plots (hemp cultivars: 'Bialobrzeskie', 'Tygra', 'Felina 32', 'Sanhtica 27', 'Futura 75') and sub-plots [fertilization treatments: control (N0), fertilizer 46-0-0 at 120 kg ha -1 (N1), 180 kg ha -1 (N2), 240 kg ha -1 (N3)]. For the computation of height, biomass yield, stem dry weight, length and weight of the inflorescences and mean seed weight, 10 plants were randomly selected in each plot. In general, increasing N fertilization rate positively impacts hemp biomass yield, stem dry weight, plant height, and inflorescence indices. Biomass yield, stem dry weight and inflorescence weight increased by 37.3%, 48.2% and 16%, respectively, with the application of 240 kg N ha -1 when compared with the unfertilized control. Plant height and inflorescence length increased from 1.66 to 1.76 m and from 66.2 to 82.9 cm, respectively, with the application of the higher N rate compared with the control, while there were no significant differences between the fertilization treatments for mean seed weight. The varieties 'Tygra' and 'Futura 75' showed the highest values for all the measurement characters. Our results indicate that hemp responded well to the addition of N fertilizer.

Impact of N, P, K, and Humic Acid Supplementation on the Chemical Profile of Medical Cannabis (Cannabis sativa L)

“…Only a small number of scientific studies have been performed dealing with cannabis nutrition and most of these studies focused on hemp varieties grown for fiber. Regarding hemp, N supplementation produced increased height and biomass (Papastylianou et al., 2018). Interestingly, very little response was observed using P or K fertilization treatments (Aubin et al., 2015).…”

Planting Density and Fertilization Evidently Influence the Fiber Yield of Hemp (Cannabis sativa L.)

“…Hemp has attracted much attention from the market and from researchers due to its multiple uses, therefore, improving the production of hemp fiber through research will help promote the promotion and competitiveness of hemp products [26,27]. Many studies have focused on the effects of N fertilizer application rate and planting density on the growth and fiber yield of hemp [15,18,28], but the current study is the first to provide a comprehensive analysis of the effects and interactions of NPK fertilizer application rates and planting density on hemp fiber yield. Because hemp for the fiber industry has the characteristics of high biomass and rapid growth, a large amount of fertilizer is required during the growth period.…”

“…Its growth is sensitive to environmental factors, particularly fertilizers. Of these, the demand for nitrogen by fiber type hemp is greater than that for phosphate or potassium [15,16]. An appropriate planting density allows for efficient use of available resources, such as light, water and nutrients, by the crop, significantly increasing yield of hemp fibers [17,18].…”

Fertility management for industrial hemp production: Current knowledge and future research needs

“…Production of ample stem biomass and high quality of hemp fibers (i.e., bast and hurd) is the goal of hemp fiber production systems and these characteristics may be impacted by N fertilization. Stem biomass tended to increase with increased N fertilization in the literature reviewed (Black & Vessel, 1945;Campiglia et al, 2017;Ivanyi & Izsaki, 2009;Papastylianou et al, 2018;Struik et al, 2000;Van der Werf, Van Geel, et al, 1995). However, increased N fertilization has produced stems with weak, coarse fiber or lower fiber content (Black & Vessel, 1945;Hessler, 1947) and stems with above optimum diameter (Jordan et al, 1946), indicating reduced breaking strength of these fibers.…”