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Resposta do cânhamo (Canabis sativa) à densidade de sementeira e fertilização azotada
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Advisor(s)
Abstract(s)
O cânhamo já foi uma cultura muito importante. Durante a época dos Descobrimentos os navios utilizavam até cem toneladas de cordas e têxteis para as velas feitas de cânhamo. Recentemente foram identificados cerca de vinte e cinco mil produtos manufaturados com cânhamo. Os objetivos deste trabalho foram estudar a resposta da densidade da plantação e da fertilização azotada na produtividade de fibra e de semente na cultura do cânhamo. Os ensaios foram conduzidos com irrigação em dois locais no nordeste de Portugal, em Bragança (na Terra Fria) e em Mirandela (na Terra Quente). A cultura foi semeada em três densidades (25, 50 e 100 kg ha-1) e adubada com três doses diferentes de azoto (50, 100 e 200 kg ha-1). Foi também incluída uma modalidade testemunha, sem fertilização azotada, e três repetições de cada tratamento. Os resultados mostraram que ambos os fatores em estudo, densidade de plantação e adubação azotada, tiveram influência na produtividade de uma forma não linear. A maior produção de fibra neste ensaio foi obtida com a cultura semeada na densidade de 25 e 50 kg ha-1 de semente e com uma adubação de 100 kg N ha-1. Com uma adubação superior a 100 kg N ha-1 verifica-se uma diminuição na produtividade que poderá ser justificada por desequilíbrios nutricionais associados ao excesso de azoto. A maior produção de semente neste ensaio foi obtida nos tratamentos com a menor densidade de plantação e nas três menores dosagens de azoto.
Hemp is a historically important crop. During the geographical exploration period ships would use up to one hundred tons of cordage and textiles for sails made from hemp fibre. In recent years up to twenty-five thousand products originating from the plant have been identified. The aim of this study was to test the response of nitrogen fertilization and plant density on productivity of plant fibre and seed. The crop was grown with irrigation on two sites in north-east Portugal, in Bragança (locally known as cold land) and Mirandela (warm land). The crop in this trial was subjected to three different planting densities (25, 50 and 100 kg ha-1) and three different nitrogen rates (50, 100 and 200 kg ha-1) and a non-fertilized control. The experiment was arranged as a factorial design with three replicates. The results showed that both parameters, plant density and nitrogen fertilization, had non-linear influence on crop productivity. The highest production of fibre in this trial was achieved with the crop sown with either 25 or 50 kg ha-1 of seed and fertilized with 100 kg N ha-1. It is argued that the productivity decreased above 100 kg N ha-1 due to excess of nitrogen application. The highest seed production was achieved in the treatments with the lowest plant density and the three lowest nitrogen rates.
Hemp is a historically important crop. During the geographical exploration period ships would use up to one hundred tons of cordage and textiles for sails made from hemp fibre. In recent years up to twenty-five thousand products originating from the plant have been identified. The aim of this study was to test the response of nitrogen fertilization and plant density on productivity of plant fibre and seed. The crop was grown with irrigation on two sites in north-east Portugal, in Bragança (locally known as cold land) and Mirandela (warm land). The crop in this trial was subjected to three different planting densities (25, 50 and 100 kg ha-1) and three different nitrogen rates (50, 100 and 200 kg ha-1) and a non-fertilized control. The experiment was arranged as a factorial design with three replicates. The results showed that both parameters, plant density and nitrogen fertilization, had non-linear influence on crop productivity. The highest production of fibre in this trial was achieved with the crop sown with either 25 or 50 kg ha-1 of seed and fertilized with 100 kg N ha-1. It is argued that the productivity decreased above 100 kg N ha-1 due to excess of nitrogen application. The highest seed production was achieved in the treatments with the lowest plant density and the three lowest nitrogen rates.
Description
Keywords
Canhamo Cannabis
Citation
Eje, Röndahl; Arrobas, Margarida; Queijo, Luís; Rocha, João; Rodrigues, Manuel Ângelo (2017). Resposta do cânhamo (Canabis sativa) à densidade de sementeira e fertilização azotada. In V Encontro de Jovens Investigadores: Livro de resumos. Bragança. ISBN 978-972-745-235-4
Publisher
Instituto Politécnico de Bragança