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 no-till plots in 2007, SQI = soil quality index, ΔSQI = rate of change in soil quality index 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