CONCENTRAÇÕES DE NITROGÊNIO NA SOLUÇÃO NUTRITIVA E HORÁRIOS DE COLHEITA NO TEOR DE NITRATO EM RÚCULA

Abstract

Hydroponics is a method of culture which offers producers a larger number of cycles throughout the year, and value aggregated to vegetables. Empiricism, however, in the use of nutritive solutions, and the non-adoption of harvest times at which lower nitrate content can be achieved, may lead to a drop in produce quality due to the accumulation of nitrate. An experiment using a hydroponic method, the NFT, was conducted in the spring of 2003, in Jaboticabal, SP, aimed at evaluating nitrogen concentration in the nutritive solution (60,8; 121,6; 182,5; 243,5 mg L-1), rocket cultivars (Cultivada, Folha Larga and Selvática) and harvest time factors (7 a.m., noon and 5 p.m.) in nitrate content of rocket. The experiment was carried out in a randomized blocks design and a 4 x 3 x 3 factorial design, with four replications. For nitrogen concentration in the nutritive solution of 93 mg L-1, which showed higher MFPA, nitrate content was 598,4 mg kg-1 NO3 - fresh matter for rocket harvested at 7 a.m.