Desempenho Agronômico de Alface e Rúcula em Função de Doses de Composto Fermentado em Condições de Cultivo Protegido, sob Manejo Orgânico em Nova Friburgo, RJ

Abstract

The fermented compost, type Bokashi, represents an alternative of organic compost to organic farmers who do not have, or chose not to use compost made of animal manures. The Bokashi can be prepared with different sources of organic materials. Inoculation with efficient microorganisms (EM) is necessary to guarantee a regularity in the offer of this compost, allowing a fermentation in the maximum of twenty days. The objective of the present dissertation is to evaluate the effect of different doses of fermented compost, which was made with wheat bran and castor cake, on the yield and level of nutrients of lettuce and roquette plants, organically grown and in succession. The experiment was developed at Sítio Cultivar, located in Nova Friburgo, on the Mountain Region of Rio de Janeiro, between the months of March and May of 2013. The experiments were conducted in blocks, in a factorial design of 5x2, with four replications. The treatments consisted of five doses of compost (equivalents to 0, 50, 100, 150 e 200 kg de N ha-1, corresponding to 0, 1, 2, 3 and 4 t/ha respectively, of compost) and two succession plantings (lettuce-roquette and roquette-lettuce). The compost was applied five days before the implementation of the experiment. The cultivar used for lettuce was Amanda, and for roquette was Rococó. After the harvest of the first culture of the succession, it was proceeded the planting of the second culture, without the application of fertilizers. Samples of vegetal tissue of the two cultures were taken at the end of each cycle, being evaluated the following characteristics: fresh and dry biomass, diameter (for lettuce), height (for roquette) and number of leaves. The samples of vegetal tissues were dried at 65ºC and submitted to analysis to determine the levels of macronutrients. Soil samples were collected five days before the transplantation, one before fertilizing and another right after fertilizing, and a new sample was taken at forty five days after the transplant of the last cycle in succession. The levels of soil nutrients such as P, K, Ca, Mg and Al, as well as the soil pH were evaluated. The obtained results were compared by F test, for analysis of variance, to the factor succession plantings, and by regression analysis to the factor doses of compost. Lettuce and roquette yields showed satisfactory results for all the doses of compost, although there were not significant differences among them. In relation to succession planting, the best results were related to the succession roquette-lettuce. It was concluded that the usage of fermented compost, type Bokashi, is an alternative for organic production of lettuce and roquette, in the Mountain Region of Rio de Janeiro.