Use of Sewage Sludge for Production of Seedlings of Eucalyptus Sp.

The forestry sector is characterized as an extensive production chain, capable of propelling the development of a region as long as it is done in a critical and planned manner. Allied to this, it is the need for producing large quantities of seedlings and the substrate utilization. The objective of the research is the development of a substrate that is economically fair and environmentally friendly through proper disposal of sludge generated at wastewater treatment plants. A composting was carried out using residues such as sawdust and sludge arising from the treatment of sewage station in Cardoso/SP, Brazil. We will analyze the development of two species of eucalyptus (Corymbia citriodora and Eucalyptus camaldulensis) on three substrates: 1) commercial substrate for forest species production - control; 2) substrate with sewage sludge and sawdust (composted) in the ratio of 1:3 (v:v); 3) substrate with sewage sludge and sawdust (composted) in the ratio 1:2 (v:v). These mixtures have already been composed for four months, with irrigation and periodic turnings. The plants are growing in full sun. At the end of the experiment, the following parameters of seedling development will be examined: length aerial part of seedlings (measured in cm); length of the root system (measured in cm); collar diameter (with a digital caliper - 0.01 mm); dry matter of the aerial part (in forced air circulation drying oven at 70 °C for 72 hours); dry matter of root system (in forced air circulation drying oven at 70 °C for 72 hours). After this period, the material will be weighed on an electronic precision balance. Preliminary results indicate a good germination of the two species with better visual quality for the seedlings grown in substrate containing sewage sludge.