Fig. 1.

Schematic representation of experimental design. Regions of differing soil quality are indicated by regions of darker shading. High-quality soil contained 66% manure mixed with background soil (vol/vol), low contained 25%, poor 4%, and background soil 0%. Transparent plastic tubes spanned the length of each box so that roots traveling away from the shoot could be visualized through the use of a minirhizotron camera inserted into the tubes. Minirhizotron tubes below the soil in the schematic are indicated by dashed lines and are shown for the Hom treatment only. Distance traveled by roots searching for nutrients in the soil was measured as the distance from the base of the shoot to the farthest visible root either toward patches, or away from patches. Schematic is not to scale.