Comparison of saturated hydraulic conductivity, by the falling-head method, on four agricultural soils

A study of agrichemical transport and fate in soil-water systems is being conducted using laboratory soil columns. In-tact soil columns were collected in four agricultural soils in Ohio and Indiana; Blount silt loam; Brookston silty clay; Rossburg sandy loam; and Clermont Silt loam. Column diameter is 30 cm; soil core length ranged between 76 and 102 cm, depending on site conditions. Before conducting agrichemical transport tests, each soil-column system was analyzed to determine its physical properties. These data were used to help determine replicate soil column systems for agrichemical transport tests. This paper describes test results for saturated hydraulic conductivity, Ksat, and drainage parameters of 60 soil-column systems over four soils. The nine Brookston columns contained artificial macropores. Ksat was determined using a modified falling-head conductivity test. The mean and standard deviation in Ksat (cm/min), by soil, was: Blount - 0.277 plus or minus 0.303 (n=14); Brookston (with macropores) 6.10 plus or minus 0.7 (n=9); Rossburg -2.62 plus or minus 1.51 (n=17); and clermont - 0.316 plus or minus 0.698 (n=20). Ksat also was determined for the 14 Blount columns after a nine-month agrichemical transport test. The mean and standard deviation in Ksat was 0.233 plus or minus 0.286 (n=14), which compared well to pre-test values. The paper describes the test procedure, data analysis, gravity drainage rate data, and methodology used to determine suitable soil columns for further testing.