Solução nutritiva: avaliação da reposição de macronutrientes no cultivo hidropônico de alface.

Abstract

In the State of Pará cultivation in has been growing in the light of adverse climatic factors, which often make adaptation ofnew plant varieties ofvegetables by increasing the amount of insumos used and the incidence of pests, bringing the cost of production. The techmque of production in hydroponics protected under cultivation is a pronnsing altemative, promoting the control of climatic factors. However, the greatest difficulty is in the management and the renewal ofthe solution ofthe nutritional, insofar as many crops hydroponics obtain success, mainly due to ignorance of the nutritional aspects of the production system which requires the formulation and management of nutritional solutions. This work installed to assess the behaviour of three cuitivares lettuce conducted in hydroponics NFT system, as well as the effect of three systems reset nutrient solution in nutritional rollup nutrients and growth of cuitivares. The search was conducted in the period of 10 July to 29 August 2007, at the heart of the Federal University of Horticulture Rural Amazou (UFRA), Belém - Pará. The experixnent design was a randomized blocks, in factorial scheme 3x3, with the factors; three cultivate oflettuce (Regina, Verônica and Kaeser); and three ways ofspare ofthe nutritional solution (resetting solution nutritional made only with water; made with 50% ofthe original formula and based on the maintenance of the CE in 2.0 mS cm 1 by adding solutions adjustment). The performance of cuitivares evaluated was mfluenced by methods reset nutrients, and that management proposed by Furlam (1998), was more appropriate to the conditions under which the experiment was conducted. The results brings a new vision for the concentration ofthe solution, that in the case oflettuce, can vary from 100% to 50% of the initial proposal, without prejudice to the productivity of culture. However more diluted solutions can cause decrease in productivity proportionately the concentration of nutritional solution.