The objective of this study was to characterize the chemical properties and compositions of substrates formulated with sewage sludge in different combinations. The substrates were produced using organic waste and vermiculite, in order to obtain an adequate growth medium for the forest seedling. An analysis was made of the total and the available nutrient content on the 26 substrates, made with sewage sludge and vermiculite and waste from coconut fiber, in natura coffee straw, organic compost, carbonized rice husk and in natura rice husk, using the following ratios: 100:0, 80:20, 60:40, 40:60 and 20:80 (sewage sludge:material), and also a control consisting of commercial substrate. The commercial substrate provided the highest means for available levels of phosphorus, calcium and magnesium. The sewage sludge provided an increase of fertility of the substrates, with increased nutrient levels, mainly phosphorus, nitrogen and calcium. The substrates formulated with sewage sludge and organic compost, regardless of their ratios, were considered the most adequate for the production of seedling of forest species.
substrate fertility; plant nutrition; biosolids; organic waste
