Fig. 1. Percentage of microaggregates (53- to 250-µm) found within large (>2000 µm) and small (250- to 2000-µm) macroaggregates in 0- to 5- and 5- to 20-cm soil layers under no-tillage (NT) and conventional tillage (CT) management. (2:1 = temperate soil from Sidney [NE] dominated by 2:1 clay minerals; mixed = moderately weathered soil from Lexington [KY] dominated by mixed [2:1 and 1:1] clay mineralogy and oxides; 1:1 = highly weathered soil from Passo Fundo [Brazil] dominated by 1:1 clay minerals and oxides; ND = not determined). Values followed by a different lowercase letter within a tillage treatment, macroaggregate-size class and soil layer are significantly different among soils. Values followed by * within a soil, macroaggregate size class and soil layer are significantly different between tillage treatments. Statistical significance was determined at P < 0.05.