REDU??O DA ADUBA??O E MELHORIA DAS CARACTERíSTICAS DO SUBSTRATO COM O USO DO HIDROGEL NA PRODU??O DE MUDAS DE Eucalyptus dunnii Maiden

摘要

The aim of the study was to evaluate if the presence of hydrogel affects the physical and chemical properties of the substrate and the ratio of hydrogel in the fertilization rates of developing seedlings. In the substrate with and without hydrogel, it was carried out an analysis for the chemical and physical characteristics. The production of seedlings was conducted in a greenhouse under reduced irrigation using a randomized design factorial arrangement 2 X 6 in which the levels of factor ‘A’ referred to the presence (6 g L -1 ) or absence of hydrogel and the levels of? factor ‘B’ to the doses of controlled-release fertilizer - FLC (0; 25; 50; 75; 100 and 125% of the usual dosage). After 90 days of sowing, there was the evaluation of morphological parameters of seedlings. The use of hydrogel showed improvement of physical and chemical characteristics of the substrate, especially the attributes involving water retention and availability of the plants. Together with the addition of hydrogel and approximately 50-75% of conventional fertilization, there was an increase in height, diameter collect, dry mass, root and all, in addition to the Dickson Quality Index. Along with the use of hydrogel and fertilization over 100%, the growth of seedlings decreased. On the other hand, without the addition of the polymer, the best performance was obtained from seedlings at doses higher than 100% of conventional fertilization. In general, the use of the polymer allows a reduction of at least 25% of the conventional fertilization (6 g L -1 ), reaching up to 50%.