Layout & Design
The site is 6.2 ha (15 acres) and supports two replications of tile spacing plots at 5-, 10-, 20-, and 40-meter spacing (16, 33, 66, and 132 ft), with 0.75 m (2.5 ft) nominal tile depth and 0.4 % slope. Huts contain flowmeters and sampling equipment.
With a length of 225 meters (750 ft) and a width of at least 5 meters (16 to 132 ft) the plots are large enough for a tractor with standard equipment to do standard management practices. These plots were under continuous corn for ten years and were then under a corn-soybean rotation. They have recently been converted to a corn-corn-soybean rotation.
Drain tiles were established in the center and on the margin of each plot, so that each plot is an isolated sample collection area. The center tiles under the 5-0-, and 20- meter plots are connected to tipping bucket flow meters, which record drainage flow volume in a datalogger and also trigger an automatic sampler after a preset amount of flow. The volume of water and concentration of transported chemicals can be determined for each plot as frequently as desired.