Design, Installation, and Performance of Percolation Lysimeters for Water Quality Sampling

Abstract

Lysimeters are the primary research tool for measuring percolation and water quality. Monolithic percolation lysimeters were evaluated for measuring the quantity and quality of leachate from the root zone of irrigated crops. Six percolation lysimeters were installed in a continuous corn (Zea Mays, L.) cropping system near North Platte, Nebraska, during the fall of 1988 and spring 1989. The lysimeters were 0.9 m in diameter and 2.4 m deep. They were filled with undisturbed soil using a hydraulic pull-down method. Porous stainless steel extractors were installed vertically upward into the lysimeter bottoms, and leachate was extracted from the unsaturated soil. Leachate volume, volumetric soil water content, soil temperature, and soil bulk density were measured. Isolation of a large soil monolith in the lysimeter did not significantly affect plant growth, soil bulk density, or temperature. Soil water content near the lysimeter bottoms was greater than in the surrounding field after a wet spring in 1991. However, extractors removed most excess water and adequately matched unsaturated drainage in the field. Though leachate varied among lysimeters, they behaved similarly over time. Results will help relate irrigation management and scheduling strategies to potential leaching of soil water and associated chemicals into groundwater.