Salinity effects on yield and nutrient uptake in Cannabis sativa L

In order to study the salinity response of Cannabis sativa L. (C. sativa), nutrient solutions for hydroponic cultivation with electrical conductivity (EC) levels of 1.8, 3, 6, 9 or 12 mS cm(-1) were applied in rockwool. EC was increased either by increasing the nutrient concentrations N, P, K, Ca, Mg, S or by the addition of NaCl to a nutrient solution EC of 1.8 mS cm(-1). Shoot and bud weight of the C. sativa 'Early Haze' decreased linearly with the increase of EC when nutrient-increased ECs were higher than 3 mS cm(-1), and when the NaCl-increased ECs were higher than 1.8 mS cm(-1). The concentrations of Total THC and CBD were not affected by EC or nutrient composition. Highest cannabinoid yields were obtained at 1.8 and 3 mS cm(-1) at NaCl concentrations <= 13 mM. Leaf necrosis occurred only in the 9 and 12 mS cm(-1) NaCl treatments. Despite high Na supply, leaf Na concentrations did not exceed 30 mmol kg(-1) DM. In contrast, remarkably high Ca (>2200 mmol kg(-1) DM) concentrations were found in all treatments. Besides, low Pconcentrations (<50 mmol kg(-1) DM) in particularly the low EC-treatments were found and could be related to pH levels >7.5 in the rootzone. The results are discussed with respect to the possibilities for the cultivation of C. sativa in closed nutrient systems.