Temporal variation of soil hydraulic properties on municipal solid waste amended mine soils

Composted municipal solid waste (MSW) was applied to reclaimed surface mine spoil to quantify the impacts on the saturated hydraulic conductivity, bulk density, soil water retention, and sorptivity in the surface soil. Treatment levels of 14.0 and 28.0 Mg/ha were incorporated to approximately 130 mm on a relatively flat 0.93-ha site in eastern Kentucky. The logarithm of hydraulic conductivity increased from log(8.45 ¥ 10–8 m/s) to log(3.58 ¥ 10–6 m/s) and the bulk density decreased from 1.74 to 1.49 Mg/m3. For hydraulic conductivity results to be meaningful, hydraulic conductivity data should be transformed logarithmically prior to any statistical operation, including averaging. There was no significant difference in any parameter between the two treatment levels. Linear time variations over the three- year study were significant for the bulk density and for soil water retention, both of which decreased with time. A seasonal variation, which was statistically significant over some growing seasons and not others, occurred in hydraulic conductivity, bulk density, and soil water retention.