Construction, Calibration and Operation of a Monolith Weighing Lysimeter

Abstract

Construction of a hydraulic monolith weighing lysimeter was undertaken, however, due to inherent design and/or construction errors this proved to be an inadequate device for the accurate determination of evapotranspiration from Larrea divaricatta (creosote bush). Prior inability to stabilize the lysimeter with respect to barometric and temperature fluctuations, and eventual failure within the hydraulic transducer package led to the eventual abandonment of the hydraulic load cell design, and adoption of an electronic strain gage transducer package. This paper deals with the detailed design and construction phases of the original lysimeter, the inherent difficulties encountered, and with the modification and conversion of the lysimeter to the electronic transducer assembly. Accompanying test data with respect to sensitivity, response time and differential loading characteristics support the premise that the electronic load cell design has inherent maintenance and operational advantages over the hydraulic transducer lysimeter.