Investigations about the impact of the sowing time and rate of the biomass yield and quality of industrial hemp
¹Latvia University of Agriculture, 2, Liela str., Jelgava LV-3001, Latvia
²National University of Life and Environmental Sciences of Ukraine, 15, Heroyiv Obrony str., Kyiv UK 03041, Ukraine
The aim of this study was to find the optimum sowing rate of industrial hemp (Cannabis sativa L.) and to clarify the impact of the sowing rate on the production of biofuel from hemp biomass in Latvia. Field trials were carried out at the Research and Study Farm ‘Pēterlauki’ of the Latvia University of Agriculture in 2012–2014. The industrial hemp (Cannabis sativa L.) ‘Futura 75’ was sown in a Luvic Endogleyic Stagnosol soil: pHKCl 6.7; P – 52 mg kg-1; K – 128 mg kg-1; the organic matter content – 21–25 g kg-1. Hemp was sown in 10-m2 plots, triplicate, on May 8 and 17. The total sowing rate was 20 (100), 30 (150), 40 (200), 50 (250), 60 (300), 70 (350), 80 (400), 90 (450), and 100 (500) kg ha-1 (germinating seeds per 1 m2). The plots were fertilised as follows: N – 120 kg ha-1; P2O5 – 80 kg ha-1; and K2O – 112 kg ha-1. Hemp was harvested when the first matured seeds appeared. The biometrical indices (height and stem diameter), harvesting time, the amount of fresh and dry biomass, and the fibre content were evaluated. Depending on the sowing rate, the yield of dry matter was on average 9.2–12.1 t ha-1 when hemp was sown at the beginning of May, and 7.9–10.0 t ha-1 when hemp was sown in the middle of May.