Efeito do fósforo, nitrogênio e potássio na produção de mudas clonais de eucalipto

• Autor(a) principal: D'ávila, Flávio Siqueira
• Data de Publicação: 2008
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/2973
• topic: Eucalyptus grandis x Eucalyptus urophylla; Miniestaquia; Rustificação; Crescimento; Eucalyptus grandis x Eucalyptus urophylla; Hardening; Growth; CNPQ::CIENCIAS AGRARIAS::RECURSOS FLORESTAIS E ENGENHARIA FLORESTAL::SILVICULTURA

In forest nurseries the mineral fertilization for the production of eucalypt seedlings is a important forestry practice, because greater growth and better quality of seedlings depend very much on appropriate nutrition. The objective of this work was to evaluate the effect of phosphorus, nitrogen and potassium on the quality of seedlings of three clones of Eucalyptus spp. Two experiments were carried out in the seedling nursery of the CENIBRA enterprise: The first one evaluating the effect of doses of phosphorus in rooting substrate interacting with doses of nitrogen applied by means of fertirrigation; the one evaluating the effect of the potassic fertilization during the hardening phase. The parameters used to evaluate the quality of seedlings during the growth phase were height, collar diameter and weight of total dry mass. During the hardening phase, the parameters were height and collar diameter increment. Applying longer doses of nitrogen resulted in the greatest values for all of the morphologic parameters evaluated in the three clones. Including phosphorus in the substrate resulted in increasing values in the three clones for all of the parameters evaluated up to a determined dose, and then these parameters tended to decrease. Providing potassium in the hardening phase resulted in increased values of the collar diameter for the three clones, while that for height little influence was observed. Based on the results obtained during the growth phase, it was concluded that the use of a dose of 219 mg.L-1 of nitrogen and doses of phosphorus varying from 400 to 489 mg.dm-3 reflected positively on the quality of the seedlings, because they provided the greatest values for the morphologic parameters evaluated. During the hardening phase, it was concluded that the potassic fertilization is recommended, and that the dose of 249 mg-1 is indicated, because it promotes the greatest collar increment.