Acúmulo de macronutrientes em plantas de crisântemo sob cultivo hidropônico em argila expandida para flor-de-corte
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Data
1998-10-08
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Pesquisa Agropecuária Brasileira
Resumo
Para avaliar a eficiência do cultivo hidropônico no estado nutricional de plantas de crisântemo em relação ao cultivo convencional, realizou-se um experimento no outono/inverno e outro na primavera/verão, utilizando-se argila expandida, nas classes granulométricas 4-10, 4-13, 10-13, 13-20 mm de diâmetro, saturada duas ou três vezes ao dia por solução nutritiva recirculante com relação N-P-K:1-0,3-2.5, mais o cultivo no sistema convencional. Os plantios ocorreram em casa de vegetação da Universidade Federal de Viçosa, no ano de 1994. As plantas cultivadas em argila expandida no outono/inverno tiveram produção de material seco e conteúdos de N-P-K significativamente superiores aos das cultivadas no sistema convencional, e foram favorecidas quando o cultivo ocorreu nas três classes menores de argila expandida e com uma saturação pela solução nutritiva duas vezes ao dia. As plantas cultivadas em argila expandida no período primavera/verão tiveram uma produção de material seco e conteúdo de N, P, K e Ca semelhantes às cultivadas no sistema convencional. Essas características não foram afetadas pela freqüência de saturação com solução nutritiva e granulometria da argila expandida. Fatores como época do cultivo, temperatura e umidade, podem ter limitado a absorção dos nutrientes pelas plantas cultivadas em argila expandida, nesse período. Em todos os tratamentos, as plantas apresentaram concentrações adequadas de macronutrientes nas folhas superiores.
The experiments were conducted in fall/winter and spring/summer seasons, respectively, using expanded clay (grain sizes 4-10, 4-13, 10-13, 13-20 mm) saturated twice or three times a day with nutrient solution N-P-K (1-0.3-2.5) plus conventional production system. The plants grown in expanded clay in fall/winter seasons had dry matter production and N-P-K content significantly higher than those grown in conventional production system. These characteristics improved when planting occurred at the three smallest expanded clay grain sizes and saturation with nutrient solution was done twice a day. The plants grown in expanded clay in the spring/summer season had dry matter production and N-P-K and Ca contents similar to those grown in conventional production system. These characteristics were not affected by frequency of saturation with nutrient solution and expanded clay grain size. Factors, as planting season, temperature and moisture may have limited absorption of nutrients by the plants grown in hardened expanded clay. All treatments showed adequate levels of macronutrients in upper leaves.
The experiments were conducted in fall/winter and spring/summer seasons, respectively, using expanded clay (grain sizes 4-10, 4-13, 10-13, 13-20 mm) saturated twice or three times a day with nutrient solution N-P-K (1-0.3-2.5) plus conventional production system. The plants grown in expanded clay in fall/winter seasons had dry matter production and N-P-K content significantly higher than those grown in conventional production system. These characteristics improved when planting occurred at the three smallest expanded clay grain sizes and saturation with nutrient solution was done twice a day. The plants grown in expanded clay in the spring/summer season had dry matter production and N-P-K and Ca contents similar to those grown in conventional production system. These characteristics were not affected by frequency of saturation with nutrient solution and expanded clay grain size. Factors, as planting season, temperature and moisture may have limited absorption of nutrients by the plants grown in hardened expanded clay. All treatments showed adequate levels of macronutrients in upper leaves.
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Palavras-chave
Solução nutritiva circulante, Nutrição mineral, Produção de matéria seca