Crescimento e nutrição mineral de capim-camalote
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Data
2004-09-01
Autores
Bianco, S. [UNESP]
Barbosa Junior, A.F.
Pitelli, R.A. [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Sociedade Brasileira da Ciência das Plantas Daninhas
Resumo
Rottboelia exaltata é considerada uma das 12 piores espécies daninhas que infestam a cultura da cana-de-açúcar, pois geralmente não permite o fechamento das entrelinhas da cana quando se encontra em densidades maiores que 10 plantas por m². Com o objetivo de estudar a produção de massa seca, a distribuição e o acúmulo de macronutrientes em plantas de capim-camalote, foi conduzido o presente trabalho em condições de casa de vegetação. As plantas foram cultivadas em vasos preenchidos com areia de rio lavada e peneirada, sendo irrigadas diariamente com solução nutritiva completa de Hoagland & Arnon a 50% da concentração original. A primeira avaliação foi realizada aos 21 dias após a emergência (DAE), e as seguintes, em intervalos de 14 dias. Foi determinada a biomassa seca das diferentes partes da planta. O material foi moído e analisado quanto aos teores de macronutrientes. Os resultados indicaram que a planta apresentou crescimento durante toda a fase experimental. O maior acúmulo ocorreu aos 133 DAE, quando a planta acumulou 87,18 gramas de massa seca. Aos 133 DAE, cerca de 34,60% da biomassa seca estava alocada nas raízes, 40,29% nos colmos + bainhas, 15,13% nas folhas e 8,35% nas inflorescências. O acúmulo total dos macronutrientes foi crescente ao longo do ciclo de desenvolvimento da planta. Até 77 DAE, uma planta de capim-camalote acumula 7,14 gramas de massa seca; 132,2 mg de K; 81,5 mg de N; 32,3 mg de Ca; 18,8 mg de P; 18,6 mg de Mg; e 10,1 mg de S.
Rottboelia exaltata is considered one of the twelve worst weeds infesting sugarcane, because, in general, it does not allow suitable crop growth between sugarcane rows at weed density above 10/m². Dry matter production, distribution and macro-nutrient accumulation in R. exaltata were studied under greenhouse conditions. The plants were grown in pots filled with washed and sieved river sand, irrigated daily with Hoagland & Arnon complete nutrient solution at 50% of the original concentration. The first evaluation was carried out 21 days after seedling emergence (DAE), and the others every 14 days. The dry matter of all plant parts was determined. The material was ground and analyzed for macronutrient content. The results indicated that the plant presented slow growth up to 63 DAE, followed by fast growth from that date until the end of the experiment (133 DAE). Maximum accumulation occurred at 133 DAE, when a plant of R. exaltata accumulated 87.18 g of dry matter. At 133 DAE, about 34.60% of the dry matter was allocated on the roots, 40.29% on the stems and sheaths, 15.13% on the leaves, and 8.35% on the inflorescences. The total accumulation of macronutrients by R. exaltata was increasingly higher during plant cycle. At 77 DAE, a R. exaltata plant accumulated 7.14 g dry matter; 132.2 mg K; 81.5 mg N; 32.3 mg Ca; 18.8 g P; 18.6 mg Mg and 10.1 mg S.
Rottboelia exaltata is considered one of the twelve worst weeds infesting sugarcane, because, in general, it does not allow suitable crop growth between sugarcane rows at weed density above 10/m². Dry matter production, distribution and macro-nutrient accumulation in R. exaltata were studied under greenhouse conditions. The plants were grown in pots filled with washed and sieved river sand, irrigated daily with Hoagland & Arnon complete nutrient solution at 50% of the original concentration. The first evaluation was carried out 21 days after seedling emergence (DAE), and the others every 14 days. The dry matter of all plant parts was determined. The material was ground and analyzed for macronutrient content. The results indicated that the plant presented slow growth up to 63 DAE, followed by fast growth from that date until the end of the experiment (133 DAE). Maximum accumulation occurred at 133 DAE, when a plant of R. exaltata accumulated 87.18 g of dry matter. At 133 DAE, about 34.60% of the dry matter was allocated on the roots, 40.29% on the stems and sheaths, 15.13% on the leaves, and 8.35% on the inflorescences. The total accumulation of macronutrients by R. exaltata was increasingly higher during plant cycle. At 77 DAE, a R. exaltata plant accumulated 7.14 g dry matter; 132.2 mg K; 81.5 mg N; 32.3 mg Ca; 18.8 g P; 18.6 mg Mg and 10.1 mg S.
Descrição
Palavras-chave
Weeds, R. exaltata, Macronutrients, Planta daninha, Rottboelia exaltata, Macronutrientes
Como citar
Planta Daninha. Sociedade Brasileira da Ciência das Plantas Daninhas , v. 22, n. 3, p. 375-380, 2004.