Uso de substratos orgânicos alternativos na produção de mudas de Acacia mangium

Abstract

Acacia mangium is a vigorously growing tree species of Fabaceae, developing well in compacted and weathered soils. Native to Australia, it has been used in reforestation regions in Brazil. In this context, the production of good quality seedlings has been an important step in the silvicultural development of the species. Thus, the objective in this work was to evaluate the initial growth of Acacia mangium seedlings between 87 and 132 days under different organic substrates. The experiment was carried out in a randomized block design, arranged in a 4 x 2 factorial scheme, combining four organic substrates and two origins of A. mangium. The substrates used were: 1 - Standard Organic Substrate using 70% clayey subsoil + 30% tanned cattle manure, with 10g/L of yoorin® thermophosphate and 8.23g/L of potassium sulfate; 2 - Modified I (replacing potassium sulfate with 3g/L of potassium rock flour, KMC© product); 3 - Modified II (replacing potassium sulfate with 30% charcoal powder of the total substrate volume); 4 - Pure farmyard manure. The variables analyzed were: height (cm), stem diameter (mm), number of leaves and dry mass of shoots (g). Alternative substrates 2 and 4 provided greater dry mass accumulation in Acacia mangium seedlings. However, substrate 2 was the one that presented the best results in terms of height, stem diameter, number of leaves and dry mass of the aerial part. Origin 1 surpassed origin 2 in all parameters evaluated, thus demonstrating superior seed vigor in terms of seedling development.