| Popis: |
Infiltration is influenced by soil gases. Studies have found that CO 2 has a large impact on infiltration. Since CO 2 is highly soluble, soil flooded with it before infiltration has greater saturation and a greater infiltration rate. Our objective was to compare infiltration rates when soil pore gas consisted of (i) CO 2 at atmospheric pressure, (ii) air at atmospheric pressure, and (iii) air at various vacuum levels. A vacuum should, similar to CO 2 , reduce encapsulated gas and increase the infiltration rate. Results were that infiltration under 1- to 2-mm constant-head conditions tended to be more rapid at low air pressures. Falling-head infiltration, from 67.8- to 13.8-cm water head, was fastest with CO 2 , intermediate with a vacuum that removed all dry air gases, and slowest with air at atmospheric pressure. The final falling-head infiltration rates with CO 2 and vacuum were 1.9 and 1.6 times faster, respectively, than with atmospheric air. |
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