Solids content in soil, organic substrates and test specimens was
determined by drying samples to a constant weight at 80 C. The
volatile solids content was determined using an ashing oven set at
500 C for 4 h. pH was determined using a pH electrode (TMECC
04.11-A 1:5 slurry method, mass basis). Carbon (TMECC 04.01-A
combustion with CO2 detection) and nitrogen content (TMECC
04.02-D oxidation, Dumas method) were determined by the Service
Testing and Research laboratory at the OARDC.
Selected test specimens were also analyzed before and after soil
incubation using scanning electron microscopy (SEM) (Hitachi S-
3500N, Hitachi High Technologies America, Inc., CA, U.S.). Samples
were coated with platinum to a thickness of 0.2 kA using a
Hummer 6.2 sputtering system (Anatech USA, CA, U.S.). A 15 Kv
electron beam was applied.