Three 30-m transects were established from the center of each plantation along a randomly determined compass heading.
Every three meters along each transect, soil cores (12.5 cm long £ 4.5 cm diameter) were driven into the soil with a mallet
The following day, cores were pulled from the soil, wrapped in plastic, and placed in a cooler at t48C. Soils were transported to the laboratory within 24 h of sampling