Influência do tamanho do recipiente na qualidade de mudas de três espécies de eucalipto

Abstract

The objective of the work was to evaluate the influence of tube size on the production of seedlings of Eucalyptus urophylla, E. robusta and Corymbia citriodora, in the nursery and in field simulation up to two months after planting. The experiment was conducted in the forest nursery of the Federal University of Recôncavo da Bahia, Campus Cruz das Almas. The seeds were sown in two sizes of tubes (180 cc and 55 cc) with commercial substrate and slow-release fertilizer. The experiment was in a Completely Randomized Design, 3 x 2 factorial scheme, (three species and two tube sizes), with 4 replications. The seedlings were evaluated 30, 45, 60, 75, 90, 105 and 120 days after sowing regarding height and diameter. At the end of the production cycle (120 days after sowing), analyzes of leaf area, number of leaves, dry mass of the aerial part, dry mass of the root system, number of roots emitted and percentage of root deformations were carried out in four seedlings per repetition. of each treatment. To check the persistence of root deformations, four seedlings from each replication at the end of the production cycle were transplanted into 11 L plastic bags filled with fertilized subsoil. When transplanting the seedlings into bags, the height and diameter of each transplanted seedling were obtained. Two months after planting, the height, diameter, dry mass of the aerial part and roots were evaluated, and the root deformations of the plants were quantified. The data were subjected to analysis of variance (α = 0.05), qualitative factors were compared using the Tukey test and sequential regression analysis was used for height and diameter increments. Seedlings produced in 180 cc tubes showed the highest values of the characteristics evaluated, regardless of the species, and the production of seedlings in this container can reduce their production cycle. Among the species, E. urophylla presented the highest average height, number of leaves and dry mass when produced in 180 cc tubes The results reveal that 55 cc tubes caused root restriction to the seedlings and consequently negatively affected their development, after two months of planting in plastic bags. Root deformations persisted in plants after planting, regardless of tube volume and species. There was no statistical difference between the containers analyzed regarding the percentage of deformations and number of roots emitted, but among the species, C. citriodora presented the lowest percentage of deformations.