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Monitoring Drainage Solution Concentrations and Solute Flux in Unsaturated Soil with a Porous Cup Sampler and Soil Moisture Sensors
Author(s) -
McGuire Patrick E.,
Lowery Birl
Publication year - 1994
Publication title -
groundwater
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.84
H-Index - 94
eISSN - 1745-6584
pISSN - 0017-467X
DOI - 10.1111/j.1745-6584.1994.tb00651.x
Subject(s) - distilled water , reflectometry , water content , flux (metallurgy) , potassium bromide , drainage , soil test , chemistry , soil water , soil science , porosity , hydrology (agriculture) , analytical chemistry (journal) , environmental science , chromatography , geotechnical engineering , geology , time domain , ecology , organic chemistry , computer science , computer vision , biology
Soil solution samples are often collected and analyzed without consideration for either the drainage period or changes in solution or solute flux. A sampling method to assess the vertical flux of solution and solute in the unsaturated zone was evaluated. Potassium bromide (KBr) solution and distilled water were applied to the surface of a soil. Estimated and measured solution and solute discharge through the soil column were compared. The column consisted of Plainfield sand (mixed, mesic, Typic Udipsamments) packed in a 208‐liter cylinder. Following solution application, discrete samples were collected at one‐ to two‐hour intervals with a ceramic soil solution sampler centrally located in the column. In each test, the Br concentrations of discrete samples were measured, and the Br concentration of a time‐integrated composite sample was calculated. Solution flux was estimated by monitoring vertical soil‐water tension and content gradients with tensiometers and time domain reflectometry probes, respectively, and applying the unsaturated form of Darcy's equation. In three of four tests, differences between measured and estimated solution discharge were 20%. Differences in measured and estimated Br mass discharge ranged from 1 to 37%. Correlation coefficients between estimated and measured Br mass discharge based on discrete and composite sample concentrations were 0.905 (p = 0.095) and 0.70 (p = 0.30), respectively.