Low-Cost Electronic Weighing Lysimeters

Evapotranspiration research lysimeters with 1 nfi area and 1.2 m depth were designed and constructed using commercially available cantilever load cells. These lysimeters were operated continuously for a three-year period at the Drainage Research Farm of Utah State University. Resolution of daily measurements of evapotranspiration (Et) from the fescue/forage grass mix was generally better than 0.05 mm or 1%. Accuracy of hourly measurements of E^ was influenced by numerical resolution of the data logger and slight thermal instabilities within the load cells. Lysimeter measurements agreed well with Et estimated with the Penman-Monteith method. The total cost for a two-lysimeter installation including labor was $11,000. Maintenance and operation requirements were low.