Initial = data collected from conventionally tilled (CT) continuous corn (CC) plots in 2002, CT2007 = data collected from conventionally tilled plots in 2007, NT2007 = data collected from continuous no-till plots in 2007, Cmic = microbial biomass carbon, BR = basal respiration rates, qCO2 = specific maintenance respiration rates, SBQ = soil biological quality, ΔSBQ = rate of change in soil biological quality, and ns = non-significant.
*
Means followed by same upper case letter (X to Z) in the column were not significantly different at p ≤ 0.05 over time (2002 vs. 2007).
+
Means followed by same lower case letter (a to c) in the column were not significantly different at p ≤ 0.05 between tillage treatments in 2007.
#
Indicates significant tillage and soil depth interaction.