AMMI analysis of bacterial T-RFLP datasets from agricultural (a) and prairie (b) soils. TRFLP profiles were examined within management history, thereby eliminating variance due to differences in management. Each site was treated as an individual sample without replication to examine the amount of variance due to site within each management history. Different colors and symbols represent the five sites from agricultural (a) and prairie (b) soils. 1 = 0 – 10 cm; 2 = 10 – 20 cm; 4 = 20 – 40 cm.