Quality of African mahogany seedlings in substrates with soils from the Cerrado biome

Abstract

The organic residues can be used in the composition of substrates, but there is a need to demonstrate the technical efficiency of organic residues. The objective was to evaluate substrates composed of varying proportions of soil of different texture and organic residues, in order to obtain good quality African mahogany seedlings. The experiment was carried out in two stages, one in a forest nursery and the other in the field, both located in the Cerrado biome, Western Maranhão, Northeast region of Brazil. The design was in randomized blocks, with eleven treatments and seven replications. The morphological variables of growth and quality were evaluated for 105 days in the nursery and 270 days in the field. The results showed that all substrates produced seedlings with adequate robustness and Dickson quality index. The seedlings produced in substrates with proportions ranging from 70 to 30% of soil, 15 to 30% of tanned cattle manure and 15 to 20% of carbonized rice husks presented a better quality standard, considering the higher values of nutrient content, morphological characteristics and Dickson quality index. However, when planted in the field, only seedlings that were produced in substrates with clayey textured soil, with up to 20% of carbonized rice husk, showed greater growth in height, as the substrate remained adhered to the root when removed from the container. Therefore, the adherence of the substrate to the root system of the seedlings was the main factor for the greater growth of the seedlings under field conditions.