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An Automated Vacuum Extraction Control System for Soil Water Percolation Samplers
Author(s) -
Lentz R. D.,
Kincaid D. C.
Publication year - 2003
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj2003.1000
Subject(s) - solenoid valve , environmental science , soil water , percolation (cognitive psychology) , water content , extraction (chemistry) , soil science , vacuum pump , materials science , geotechnical engineering , chemistry , geology , electrical engineering , engineering , mechanical engineering , chromatography , neuroscience , biology
A vacuum applied to soil water percolation samplers permits collection of both macro‐ and matrix‐pore liquids. Performance of these field samplers is improved when the extraction vacuum is adjusted in accordance with the tension in the surrounding soil. This is particularly important when monitoring a network of spatially distributed samplers and for samplers installed in medium to fine textured soils. We designed a vacuum extraction system to more efficiently collect vadose‐zone soil solution samples. A single vacuum pump, vacuum tank, and air dryer provided a vacuum supply for 12 soil water sampling sites via a branching polyethylene pipe network. A vacuum controller containing two inexpensive pressure transducers, a voltage regulator, relay, and solenoid valve was developed and tested for field installation. Data loggers operated the controllers, monitored extraction vacuum and ambient soil water potential, and adjusted relative vacuum at each percolation sampling site. The automated vacuum controllers successfully maintained sampler extraction pressures at levels proportional to ambient soil water potential and provided the added benefit of recording the pressure values for use in subsequent data interpretation.