Acúmulo e exportação de n p k em plantas de alface e coentro produzidas em sistema orgânico

Abstract

The vegetables produced in organic production system have strong consumer acceptance, due to obtain sound products, free of chemical contaminants. However, the nutritional requirement and efficient use of nutrients are poorly studied for such systems. The objective was to obtain curves of march absorption for nutrients: nitrogen (N), match (P) and potassium (K) in vegetables, lettuce and coriander, grown in organic system. The plant material was collected at the site Carcará, in Guaraciaba do Norte municipality. The design was completely randomized, with treatments consisting of six of plant development stages, with five repetitions. The plant material was dried in an oven at 65°C, for 72 hours, to determine the dry weight and the chemical analysis of plant material. The accumulation of dry biomass per plant was slow at first third of the cycle and had a significant increase in the last two-thirds. The accumulation of nutrients N, P and K followed biomass in both cultures, and lettuce accumulating on average, only 4,2% of N, P and K in the leaves in the first third of the cycle vegetative and the remaining 95,2% in the second third of the cycle, while coriander accumulates on average 15,3% of N, P and K in the first third of the cycle vegetative and the remaining 84,7% in the second third of the cycle. With lettuce production estimated at 1.560kg ha-1 dry matter the export of N, P and K was 21,9; 11,8 and 116,9 kg ha-1, respectively, to coriander, with estimated production of 3,389 kg ha-1 dry matter, export of N, P and K was 27,5; 19,2 and 201,2 kg ha-1, respectively. Based on the contents of N, P and K in the aerial part of the lettuce plants and coriander, it is suggested that, fertilization using the organic compound in the experimental area does not meet the need of nitrogen to plant lettuce and coriander.