AMMI analysis demonstrating differences in TRFLP patterns due to depth and management history (a) or site (b). TRFLP profiles with each site treated as an individual sample without replication. The two panels show the same data, but labeled with different symbols, illustrating differences due to (a) depth and management history and (b) site. In panel (a), closed circles represent agricultural soils; open circles represent prairie soils. 1 = 0 – 10 cm; 2 = 10 – 20 cm; 4 = 20 – 40 cm. In panel (b), different colors and symbols represent the five sites.