Development and production of cabbage (Brassica oleracea var. Royal vantage) under different osmotic pressures and biofertilized with bacterial consortia
The development and production of cabbage (Brassica oleracea var. Royal vantage) in a greenhouse, under different osmotic pressures of the Steiner nutrient solution and biofertlized with bacterial consortiums, were evaluated. A 4 × 3 factorial design was established, where the factors were four levels of osmotic pressure (0.18, 0.36, 0.54 atm and a control without nutrient solution), and two bacterial consortia: Azospirillum brasilense + Acinetobacter calcoaceticus (AA) and Raoultella terrigena + Chromobacterium violaceum (RC), and an uninoculated control. Six repetitions were established for each treatment. Seeds inoculated with the consortium AA had the highest emergence percentage (100%), as well as the highest emergence rate (20.5), compared with the consortium RC and the non-inoculated plants. Inoculation with the consortium AA and the osmotic pressure of 0.54 atm produced taller plants (60-65%), and a stem with a larger diameter (35-46%). The weight of the fresh biomass and the accumulation of dry material doubled in the inoculated plants compared to the non-inoculated ones. A higher concentration of K was observed in plants inoculated with AA and RC (20‑35% and 25-45%, respectively) compared to non-inoculated plants. The nitrate concentration in the plants increased between 200-350% and 60-230% with the inoculation of consortia AA and RC, respectively. The P concentration increased between 200-500% with the consortium AA and between 100-400% with the consortium RC. Inoculation with the consortia AA and RC, at osmotic pressure of 0.54 atm, induced the greatest development of the cabbage heads (classif ied as 5 and 4, respectively). It is concluded that cabbage, under moderate mineral fertilization in a greenhouse, responds favorably to the inoculation of plant growth promoting bacteria.