Efeito de diferentes substratos sobre o desenvolvimento de mudas de Acacia sp.

Sewage sludge has been studied as source of organic matter on seedling production. Thus, this study aimed to evaluate the development of Acacia mangium and Acacia auriculiformis seedlings in the following substrates: a) oxic horizon + sand (1:1, v:v) + 160, 640 e 160 g m-3 of N, P2O5 and K2O respectively (HB); b) oxic horizon + sand + cattle manure (1:1:1, v:v) (HBE); c) oxic horizon + sand + sewage sludge (1:1:1, v:v) (HBL) and; d) 100% sewage sludge (LE). The substrates were limed with 1 kg m-3CaCO3 p.a.. Seeds, inoculated and non-inoculated with Rhizobium, were used, and 90 days after planting, measures of collar diameter, plant height, and root and shoot dry matter (with determination of N, P, K, Ca and Mg) were taken. The experimental design was completely randomized blocks, in a factorial 2 x 4 arrangement (with or without inoculation x 4 substrates). Better performance in seedling growth was obtained in the LE substrate with inoculated seeds. Comparatively, the HBE substrate was superior to the HBL substrate. There were no significant differences for most evaluated parameters in the HBE, HBL and HB substrates due to inoculation, probably because the existence of native bacteria in these substrates. The seedlings developing in the LE substrate accumulated more N and Ca, mainly when inoculated. There was a tendency of larger P, K and Mg accumulation in shoots of seedlings developing in the HBE substrate.