Curly lettuce development, nutrient absorption and salinization tolerance in response to an aerobic biofertilizer produced from agro-industrial residues

Biofertilizers stimulate natural processes to increase and benefit nutrient absorption, abiotic stress tolerance and increased yield when applied to plants. The production of biofertilizers from organic residues is a sustainable way to reduce these materials through recycling. The aim of this work was to define the biofertilization management based on concentrations and doses using a non-commercial aerobic biofertilizer on three newly emerged Brazilian lettuce cultivars. Consequently, this study will help to improve organic lettuces yields in the country. The experiments were conducted in a greenhouse. The soil used for cultivation was a clayey Rhodic Ferralsol. Due to the high electrical conductivity (EC) observed in the biofertilizer a first experiment was conducted to determine the optimum concentration (0%, 5%, 10%, 15%, 20% and 100%) for the three lettuce cultivars (BRS Leila, BRS Lélia and BRS Mediterrânea). After finding the best concentration, a second experiment was developed to estimate the optimum dose of the biofertilizer based on the nitrogen requirement (N) for this crop (0 kg ha-1 of N, 50 kg ha-1 of N, 100 kg ha-1 N, 150 kg ha-1 N and 200 kg ha-1 N). The experimental design was completely randomized (DIC) with a factorial scheme. The results showed that 5% concentration of biofertilizer presented better results for the development of BRS Mediterrânea and BRS Lélia. BRS Leila presented better development when fertilized with the 10% biofertilizer concentration. The dose of 150 kg ha-1 of N allowed a better development of lettuce and greater supply of nutrients to the plants.