Effects of plant density on chemical composition of basil grown within gullies by subirrigation.

Research was carried out in winter Campaigns of 2003 and 2004, with the purpose of evaluating the leaves quality characteristics of Ocimum basilicum L. (cv. ‘Gecom FT’) grown in pot, under plastic (IR-PE) tunnels equipped with an air heating system. Comparisons were made of four densities (9, 12, 15, 18 plants per pot) and a randomised complete block design was arranged with three replications; each treatment included 30 plants. The NFT equipment consisted of: a) rigid PVC gullies (each 12 cm wide and deep and 300 cm long) held at 70 cm above ground level; b) plastic tanks holding 220 L; c) submerged pumps of 90 watt unit power; d) delivery and return overhead lines. The pots, filled with peat and lapil (1:1 in volume), were placed on the gullies, on January 15th, through a pierced white PE film and spaced 10 cm along the rows (18 per m2). The leaves quality parameters always displayed decreasing trends as a function of the plant density increase, except for sucrose which did not vary. The 9 plants per pot level was more effective than the one of 12 plants, except for chlorides and potassium accumulation, whereas the 9–12 range best influenced the remaining variables. The nitrates concentration showed an opposite trend in comparison with the other analysed parameters, as it increased from the lowest to the highest plant density.