High‐resolution laboratory lysimeter for automated sampling of tracers through a 0.5 m soil block

Abstract

A computer-controlled, automated sample collection from a 0.5-m lysimeter, designed to give superior temporal and spatial resolution for monitoring the movement of chemical tracers through a large undisturbed soil block, is described. The soil block, 0.5 x 0.5 x 0.5 m, was monitored for saturation using eight time domain reflectometry probes. Rainfall was applied at approximately 1600 ml h(-1) using a 12212 array of 23-gauge (0.318 mm internal diameter) hypodermic needles. Soil leachates were collected at the base of the soil block using a machined aluminium collection plate with a 10 x 10 grid of funnels that passed leachates to sample collection palettes. Sample collection was automated using a personal computer equipped with National Instruments LabVIEW software and linked to sensors for palette tracking. The automation of the lysimeter allowed sample collection and storage over a user-defined period with no human interaction. As an example of the use of the automated lysimeter, results show the distribution of phosphate within the soil. The eluted phosphate showed an initial and secondary peak, and only emerged from preferential flow channels.

A Data Acquisition System Based on Outlier Detection Method for Weighing Lysimeters

“…Many works have been done in the construction and installation of weighing lysimeters and the measuring principle of the weighing lysimeter was described [3][4][5][6]. Some advanced data acquisition systems equipped with high-precision load-cell for the weighing lysimeters have been developed [7][8][9]. Much attention has been paid to the research on the application of the weighing lysimeter.…”

Automated System for Collecting Multiple, Sequential Samples from Soil Water Percolation Samplers under Continuous Vacuum

“…This would allow researchers to better examine the dynamic character of soil water chemistry and transport, which may result from temporal changes in 1) soil temperature in response to diurnal forcing; 2) soil water percolation and solute concentration during rain storm events; or 3) the proportion of matrix-pore vs. macro-pore flow contributions to seepage. Johnson et al (2003) developed an automated sampling system for collecting soil water from zero-tension lysimeters, where water dripping from soil was captured in different individual containers over time. Chendorain and Ghodrati (1999) designed an automated instrument that performed continuous, real-time analysis of water extracted by peristaltic pump from a nearly saturated soil column NC > -2 kPa).…”

Characterisation of flow paths and saturated conductivity in a soil block in relation to chloride breakthrough

“…Investigations have focused primarily on observations at the core and small block scales (Radulovich et al, 1992;Tindall et al, 1992;Cote et al, 1999;Johnson et al, 2003) where boundary conditions are easiest to control. These experiments have provided important information about the relationship between pore size distribution, solute dispersion and variation in hydraulic conductivity (Bowman et al, 1994;Quisenberry et al, 1994;Buchter et al, 1995).…”