Effect of sowing and fertilization rates on the weeds suppression in crop of hemp (Cannabis sativa L.)

Abstract

The research was carried out at the Upytė Experimental Station of the Lithuanian Research Centre for Agriculture and Forestry in 2015–2016. The effect of sowing rate (50, 75, 100 kg ha^–1) and fertilization rate (N₀P₀K₀; N₄₅P₄₅K₄₅; N₄₅P₄₅K₄₅ + N_34.4; N₄₅P₄₅K₄₅ + N_68.8) on the weeds suppression in the crop of hemp cultivars ‘Uso 31’ and ‘Felina 32’ was evaluated. It was found that in the crop of both investigated cultivars the least amount of declined weeds was when growing hemps without fertilizers. A positive, strong, moderately strong and statistically significant correlation (P < 0.05) was identified between the fertilization rate and the amount of declined weeds. Increasing the sowing rate of the investigated hemp cultivars resulted in an increase of the amount of weeds declined during vegetation. A positive, strong, moderately strong and statistically significant correlation (P < 0.05) was obtained between the sowing rate and the amount of declined weeds during vegetation, except cultivar ‘Uso 31’ under meteorological conditions favourable for hemp growing.