Nutrient contents and production of rocket as affected by nitrogen concentrations in the nutritive solution
Carregando...
Data
2008-12-01
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade de São Paulo (USP), Escola Superior de Agricultura Luiz de Queiroz (ESALQ)
Resumo
O empirismo no uso das soluções nutritivas é freqüente. Muitas vezes a mesma solução nutritiva é usada para diferentes espécies baseando-se apenas em semelhanças morfológicas. No entanto esta situação pode proporcionar desequilíbrio nutricional prejudicando tanto a produção quanto a qualidade do produto face o acúmulo de nitrato. Foi conduzido um trabalho em sistema hidropônico - NFT, com o objetivo de avaliar o efeito da concentração de nitrogênio na solução nutritiva na produção, nos teores de nutrientes e de nitrato em folhas de rúcula (Eruca sativa). O trabalho foi conduzido na primavera de 2003. Foram avaliadas quatro concentrações de nitrogênio na solução nutritiva (60,8; 121,6; 182,5; 243,5 mg L-1) e três cultivares de rúcula (Cultivada, Folha Larga e Selvática), sob delineamento de blocos ao acaso, fatorial 4 x 3, com quatro repetições. A cv. Cultivada apresentou maior estatura e fitomassa fresca de folhas, não diferindo da 'Folha Larga' quanto a número de folhas, teor de nitrato nas folhas e fitomassa seca e fresca da raiz. Houve incremento de NO3-, N, Ca e P e diminuição de Mg, K e S com o aumento da concentração de N na solução nutritiva. O cultivo da cv. Cultivada na concentração de 93 mg L-1 é a mais recomendada em função da maior produtividade e baixo teor de nitrato.
Empiricism in the use of nutrient solutions is frequent. Several times the same nutrient solution is used to grow different species based only on morphological similarities. This practice may lead to nutritional imbalances, affecting not only the production but also the quality of the product due to an accumulation of nitrate. An experiment under hydroponic conditions - the NFT system - was conducted with the aim of evaluating the effect of the concentration of nitrogen in the nutrient solution on the production and on the nutrient and nitrate contents of rocket (Eruca sativa) salad leaves. The experiment was carried out in spring 2003, in a randomized block design and in a 4 x 3 factorial design, with four replicates. Four nitrogen concentrations in the nutrient solution (60.8; 121.6; 182.5; 243.5 mg L-1) and three rocket salad cultivars (Cultivada, Folha Larga and Selvática) were evaluated. Cv. Cultivada produced the tallest plants and the highest leaf fresh fitomass, not differing from cv. 'Folha Larga' in the number of leaves, leaf nitrate content, root dry fitomass and root fresh fitomass. An increment in NO3, N, Ca and P and a reduction in Mg, K and S occurred when the concentration of N in the nutrient solution was increased. Cultivation of cv. Cultivada at the concentration of 93 mg L-1 is the most recommended as it provides the highest yield and low nitrate content.
Empiricism in the use of nutrient solutions is frequent. Several times the same nutrient solution is used to grow different species based only on morphological similarities. This practice may lead to nutritional imbalances, affecting not only the production but also the quality of the product due to an accumulation of nitrate. An experiment under hydroponic conditions - the NFT system - was conducted with the aim of evaluating the effect of the concentration of nitrogen in the nutrient solution on the production and on the nutrient and nitrate contents of rocket (Eruca sativa) salad leaves. The experiment was carried out in spring 2003, in a randomized block design and in a 4 x 3 factorial design, with four replicates. Four nitrogen concentrations in the nutrient solution (60.8; 121.6; 182.5; 243.5 mg L-1) and three rocket salad cultivars (Cultivada, Folha Larga and Selvática) were evaluated. Cv. Cultivada produced the tallest plants and the highest leaf fresh fitomass, not differing from cv. 'Folha Larga' in the number of leaves, leaf nitrate content, root dry fitomass and root fresh fitomass. An increment in NO3, N, Ca and P and a reduction in Mg, K and S occurred when the concentration of N in the nutrient solution was increased. Cultivation of cv. Cultivada at the concentration of 93 mg L-1 is the most recommended as it provides the highest yield and low nitrate content.
Descrição
Palavras-chave
Eruca sativa, Diplotaxis tenuifolia, hydroponic system, cultivar, Mineral nutrition, Eruca sativa, Diplotaxis tenuifolia, sistema hidropônico, cultivar, Nutrição mineral
Como citar
Scientia Agricola. São Paulo - Escola Superior de Agricultura Luiz de Queiroz, v. 65, n. 6, p. 652-658, 2008.