Bioavailability and Solubility of Heavy Metals and Trace Elements during Composting of Cow Manure and Tree Litter

Table 6

Recorded parameters and measurement dates for each stage of the investigation.

Stage	Primary variables	Secondary variables	Measurement date
Characterization	Total content (HMtot)	Four physicochemical variables (pH, EC, TOC, and TN)	February 13, 2014 (T111/T240)
Evaluation	Total content (HMtot), Bioavailability (HMDTPA) and solubility (HMH2O)	Eleven physicochemical variables (T°, H%, pH, EC, TOC, TN, NH4^+-N, HA, FA, OM, and Da)	February 2, 2016 (T0);
		Twelve microbiological variables (mesophilic aerobes, thermophilic aerobes, Lactobacillus spp., molds and yeasts, total coliforms, fecal coliforms, Escherichia coli, Salmonella spp., Pseudomonas spp., Bacillus spp., actinomycetes, and helminths)	March 3, 2016 (T30); April 2, 2016 (T60); May 2, 2016 (T90); June 1, 2016 (T120)