Survival and initial growth in the field of eucalyptus seedlings produced in different substrates

The objective of this work was to evaluate the survival and initial growth, in the field, of eucalyptus seedlings produced in different substrates. Eucalyptus benthamii seedlings produced in 36 substrates were evaluated in the field. The substrates consisted of mixtures, at different volumetric proportions, of: carbonized rice husk, charcoal with granulometry between 1.0-3.0 mm, charcoal with granulometry between 3.0-5.0 mm, coconut fiber, semi-decomposed pine bark, fine vermiculite, sewage sludge, and peat moss. At 1, 2, 3, 6, 12, 18, and 24 months after planting, survival, height, and diameter were determined. At 24 months after planting, height increment, diameter increment, transversal area, and basal area were also measured. The seedlings that showed 100% survival after 24 months under field conditions were those grown in the nursery in substrates with a higher proportion of fine vermiculite, sewage sludge, and peat moss, that is, in substrates with a higher microporosity. However, there is no effect of substrate characteristics on seedling initial growth in the field. A significant correlation is observed between the survival of seedlings at 6 months and their diameter at the end of the nursery period, evidencing the importance of this characteristic for the establishment of the plant in the field, regardless of the used substrate. Resumo: O objetivo deste trabalho foi avaliar a sobrevivência e o crescimento inicial, no campo, de mudas de eucalipto produzidas em diferentes substratos. Mudas de Eucalyptus benthamii produzidas em 36 substratos foram avaliadas em campo. Os substratos consistiram em misturas, em diferentes proporções volumétricas, de: casca de arroz carbonizada, carvão com granulometria entre 1,0-3,0 mm, carvão com granulometria entre 3,0-5,0 mm, fibra de coco, casca de pinheiro semidecomposta, vermiculita fina, lodo de esgoto e turfa. Aos 1, 2, 3, 6, 12, 18 e 24 meses após o plantio, foram determinados sobrevivência, altura e diâmetro. Aos 24 meses após o plantio, também foram medidos incremento em altura, incremento em diâmetro, área transversal e área basal. As plântulas que apresentaram sobrevivência de 100% após 24 meses em condições de campo foram aquelas cultivadas, no viveiro, em substratos com maior proporção de vermiculita fina, lodo de esgoto e turfa, ou seja, em substratos com maior microporosidade. No entanto, não há efeito das características do substrato no crescimento inicial das plântulas. Há correlação significativa ent