Introducing a Laboratory Setup Design for Assessing the Performance of Automated Vacuum Lysimeters.

Automated vacuum lysimeters (AVL) are considerd as the most accurate soil water sampling devices. However there is still a need for a reliable method for assessing and evaluating the performance of these devices. Indirect methods (e.g. water-flow models and tracing chemicals) have been used for evaluating the performance of automated vacuum lysimeters. However the results are not completely reliable and objective. Few laboratory setups that have been used as direct methods had major technical issues and failed to create a suitable and representative environment for conducting a non-biased assessment. In this study, Dual Soil-Column System was introduced as an accurate, direct and objective method for assessing and quantifying the performance of automated vacuum lysimeters. Themethod consists of two identical and independent soil columns. The only difference between the columns is the water sampler (in this case an automated vacuum lysimeter) installed in one of the columns. Therefore it was possible to accurately study the effect of soil-water sampler on water percolation in soil profile. Statistical methods were used for evaluating the accuracy of soil-water samplers. We found that dual Soil-Column System can be used accurately for detecting and quantifying convergence and divergence of water flow caused by sampler as well as assessing the performance of soil-water samplers.