Resposta de mudas de Senna macranthera cultivadas em argissolo vermelho-amarelo a macronutrientes
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Data
2011-01
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Ciência Florestal
Resumo
Senna macranthera tem grande ocorrência natural, com potencial uso na recuperação de áreas degradadas. Entretanto, existe necessidade de informações sobre a nutrição das espécies florestais nativas. Assim, o objetivo deste trabalho foi avaliar o efeito de doses de N, P, K, Ca, Mg e S sobre o crescimento e índices de qualidade de mudas de fedegoso e determinar a dose a ser recomendada para estes. No trabalho, conduzido em casa de vegetação, utilizou-se amostras de Argissolo Vermelho Amarelo, retirado da camada abaixo de 20 cm de profundidade, como substrato. Delimitou-se o experimento por meio de matriz baconiana, avaliando-se três doses dos seis macronutrientes e dois tratamentos adicionais, um com doses de referência (adubação usada como padrão para espécies nativas) e outro sem adição de nutrientes. Adotou-se o delineamento inteiramente casualizado com quatro repetições. Foram analisados os parâmetros morfológicos e os índices de qualidade de mudas. Verificou-se, por meio de análise dos contrastes ortogonais, resposta significativa de todas as variáveis estudadas à aplicação dos macronutrientes. A espécie mostrou-se mais exigente em P e K em comparação aos demais macronutrientes, sendo recomendada dose de 600 mg dm-3 de P e 200 mg dm-3de K. Recomendam-se estudos adicionais com os nutrientes N, Ca, Mg e S, com doses inferiores às menores doses testadas, tendo em vista que, segundo dados deste estudo, as melhores doses desses nutrientes se encontram entre os teores originais do solo usado como substrato e as menores doses aplicadas.
Senna macranthera has great natural occurrence, with potential use in the recovery of degraded areas. However, there is need for information on the nutrition of native forest species. In that sense, the objectives of this study were to evaluate the effect of doses of N, P, K, Ca, Mg and S on growth and quality indices of seedlings of Senna macranthera and to determine their recommended doses. This study was carried out in a greenhouse, using a Red Yellow Argisol, removed from the layer below 20 cm depth, as substratum. The experiment was designed in a Baconian Matrix, and three doses of the six macronutrients and two additional treatments were evaluated, one with reference doses (fertilizer used by default for native species) and the other one without the addition of nutrients. An entirely casualized design was adopted, with four repetitions. The morphologic parameters and quality indices of seedlings were analyzed. Through orthogonal contrasts, a significant response of all the variables studied was verified in relation to the macronutrients applied. The species was most demanding of P and K in comparison to the other macronutrients, and the recommended doses were of 600 mg dm-3 of P and 200 mg dm-3 of K. It is recommended that further studies with lower doses of the nutrients N, Ca, Mg and S be carried out, since, according to this study, the best doses for these nutrients were found for the original soil used as substrate and the lowest dose of the applied treatment.
Senna macranthera has great natural occurrence, with potential use in the recovery of degraded areas. However, there is need for information on the nutrition of native forest species. In that sense, the objectives of this study were to evaluate the effect of doses of N, P, K, Ca, Mg and S on growth and quality indices of seedlings of Senna macranthera and to determine their recommended doses. This study was carried out in a greenhouse, using a Red Yellow Argisol, removed from the layer below 20 cm depth, as substratum. The experiment was designed in a Baconian Matrix, and three doses of the six macronutrients and two additional treatments were evaluated, one with reference doses (fertilizer used by default for native species) and the other one without the addition of nutrients. An entirely casualized design was adopted, with four repetitions. The morphologic parameters and quality indices of seedlings were analyzed. Through orthogonal contrasts, a significant response of all the variables studied was verified in relation to the macronutrients applied. The species was most demanding of P and K in comparison to the other macronutrients, and the recommended doses were of 600 mg dm-3 of P and 200 mg dm-3 of K. It is recommended that further studies with lower doses of the nutrients N, Ca, Mg and S be carried out, since, according to this study, the best doses for these nutrients were found for the original soil used as substrate and the lowest dose of the applied treatment.
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Nutrição de planta, Características morfológicas, Reflorestamento, Produção de mudas, Plant nutrition, Morphologic characteristics, Reforestation, Seedling production