The soil water maximum holding capacity (WMHC) was determined according to Frighetto & Valarini (2000); then, 74 g (dry weight equivalent) portions were placed in 24 biometer flasks (Bartha & Pramer, 1965) and had the water content adjusted to 50% WMHC. The biometer flasks remained one week in a dark chamber with controlled temperature at 25±1ºC, for reactivation of soil bioactivity. Mass of each sample was recorded for moisture correction, if necessary.