The objective of this research was to study the physical and chemical properties of substrates with different mixtures of biosolids (BIO) and carbonized rice chaff (CAC) in order to get an appropriate medium for seedling development. The experiment was established in the nursery of the Department of Natural Resources/Forest Sciences, College of Agronomic Sciences, State University of São Paulo-FCA/UNESP-Botucatu (SP), using BIO from SABESP/Franca-SP and CAC in the following ratios (BIO/CAC): 100/0, 90/10, 80/20, 70/30, 60/40, 50/50, 40/60, 30/70, 20/80, 10/90, and 0/100, which were compared to Multiplant® substrate. The evaluated physical attributes were apparent density, macro and microporosity, total porosity, maximum water holding capacity. The following chemical attributes were also determined: macro and micronutrients concentration, pH, C/N ratio, and electrical conductivity. Results showed an increase in density and microporosity with increasing BIO rates in the substrate and, consequently, an increase in the water holding capacity. Chemical analyses showed high nutrient contents in BIO, especially N and P, but a low K content. Leavy metal contents were below the limits defined by the Brazilian legislation. According to literature values considered adequate for plant growth, the satisfactory BIO rates in the substrate ranged from 30 to 60 %. No substrate, including a control with a commercial substrate, presented ideal values for all evaluated parameters.
municipal solid waste; substrate; nutrient; aeration; water retention
