Substrates for seedlings with sewage sludge and biochar.

The objective of this study was to evaluate substrates formulated with proportions of sewage sludge (SS)-solarizedand SS-biochar in the production of seedlings of two indicator crops: lettuce (Lactuca sativa L.) and black wattle(Acacia decurrens Willd). The study was composed of two experiments conducted in greenhouse, in randomized blockdesigns. The treatments consisted of five doses of SS-solarized and SS-biochar, combined with rice husk ash andvermiculite in different proportions (20:40:40, 30:35:35, 40:30:30, 50:25:25 and 60:20:20) and two commercial substrates(controls). Morphophysiological characteristics of the seedlings and the physico-hydric characteristics, pH and electricalconductivity of the substrates were evaluated. The pyrolysis process enhanced the characteristics of SS as a componentof substrates, where the substrate with 20% of SS-biochar, 40% of vermiculite and 40% of rice husk ash, presented thebetter performance