Ground and sieved (~60 mesh) soil samples were pelleted using the Carver Hydraulic Press (Carver, Inc.).
Briefly, 0.3 g of each soil sample were placed in a KBr die, and pressed for 4 minutes at 5000 pounds. Three
pellets were made for each soil sample with a pellet thickness of 1.0 mm. Pellets were scanned in the mid-IR
on a Spectrum One (PerkinElmer Instruments LLC, Shelton, CT) FT-IR Spectrometer equipped with a