A two-factorial greenhouse experiment was conducted in 2012-2014 in a greenhouse owned by the Department of Horticulture at the University of Warmia and Mazury in Olsztyn (NE Poland). The experiment had a randomized block design with three replications. The experimental factors were (1) six botanical varieties of basil: sweet basil, Thai ‘Siam Queen’ basil, Greek ‘Minette’ basil, purple basil, lemon basil and cinnamon basil, and (2) container size and the number of plants per pot: 0.7 dm3 container with one plant per pot (control), 3.0 dm3 container with one plant per pot, 3.0 dm3 container with four plants per pot. In successive years of the three-year experiment, between 22 and 24 February, containers filled with organic substrate were placed on movable tables in the greenhouse, depending on pot size (0.7 dm3 and 3.0 dm3). The organic substrate had salt concentration of 1.5 g dm–3, pH 4.99, and the following chemical composition: N-NO3 – 112 mg dm–3, P – 257 mg dm–3, K –143 mg dm–3, Ca – 480 mg dm–3, Mg – 383 mg dm–3. Total yield and marketable yield were identical, and were expressed in kg m2. Representative samples collected from the marketable yield were dried, ground and assayed for the content of nitrates(V) – by the colorimetric method with the use of salicylic acid, and heavy metals Hg and Pb – by atomic absorption spectrometry (AAS). Cinnamon basil and Greek ‘Minette’ basil were characterized by a significantly higher marketable yield of fresh herbage, compared with the remaining varieties. Botanical variety had no significant influence on the content of mercury and nitrates in herbage. The results of a three-year experiment indicate that growing basil plants in 3.0 dm3 containers, with four plants per pot, significantly decreases herbage yield, but prevents excessive accumulation of nitrates(V) and mercury in the edible parts of plants.

4.23.2018