Plant density in production of mini lettuce cultivars in organic system management

Resumo

Production of mini vegetables in organic system is a good alternative to improve profit, but there are not researches about the optimum plant density for these cultivars in Brazilian conditions. Two experiments were conducted to evaluate the production of mini lettuce cultivars in different plant density. Experiment 1 was conducted from January 01 (sowing) to February 10 (harvesting), 2012. The experimental design was completely randomized blocks, with six treatments in factorial scheme, 3 mini lettuce cultivars (Tudela, Renoir and Sartre) x 2 spacing between plants (16 and 20cm), with eight replications and plots (2.04 m²) with six rows, spaced 15cm. Experiment 2 was conducted from June 06 (sowing) to July 18 (harvesting), 2012. The cultivars Sartre and Renoir were evaluated under four plant densities (444444, 333333, 266667 and 200000 plants ha^-1, corresponding to spacing of 15 x 15, 15 x 20, 25 x 15 and 25 x 20 cm, respectively). Eight treatments were defined by a factorial scheme 2 (cultivars) x 4 (plant density) and arranged in a completely randomized block design, with nine replications and plots with 2.04 m². The characteristics evaluated in both experiments were: total fresh and marketable weight per plant, plant dry weight, plants diameter and height, marketable yield and discard percentage. In first experiment, during the summer, cultivar Sartre showed the higher marketable fresh weight. Heavier plants were obtained with the higher plant spacing, but the highest yield was obtained with the smaller one. In winter, it was obtained bigger plants in cultivar Sartre and it was obtained heavier plants in low plant density, but the higher plant density, the higher the yield.