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United States Department of Agriculture

Agricultural Research Service

Title: Effects of Experimental Parameters on Soil-Herbicides Sorption Coefficient of Field-Moist Soil Determined Using Supercritical Carbon Dioxide

Authors
item Rochette, Elizabeth
item Koskinen, William

Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: November 2, 1995
Publication Date: N/A

Technical Abstract: In this study we determined the effects of experimental parameters on soil-herbicide sorption coefficients (Kds) obtained using supercritical carbon dioxide (SF-CO2) to remove herbicides from soil water of soils with water contents below field capacity. Experimental parameters included soil type, moisture content, temperature, CO2 density, and soil moisture potential. Five soils with clay contents from 1 to 23%, organic carbon from 0.1 to 2.6%, and pHs from 4.4 to 6.2 were used. Low-density SF-CO2 Kd values for atrazine increased as the content of clay and organic matter in the soil increased. Kd values obtained with short, low-density SF-CO2 sweep periods could be obtained repeatedly from soil samples after 7-min. equilibrations between sweep periods. Little atrazine could be removed from desiccated soil with the SF-CO2 method, though increasing the soil water content from 5 to 16% notably increased SF-CO2 Kd values. In general, increasing the SF-CO2 density and temperature decreased soil-atrazine Kd values.

Last Modified: 10/30/2014