Influence of Initial Water Content and Temperature Gradients on Water Transport in Soil

A study was conducted in uniformly packed horizontal soil columns initially wetted to 0.075,0.184 and 0.280 cm³ cm⁻³ water contents. The columns were subjected to 0.5 and l°C cm⁻¹ temperature gradients by maintaining differential temperature at the ends through the heat source and the sink. At all the water contents and boundary temperatures, the soil columns attained a steady temperature and water distribution within 3–4 hours and 150 hours, respectively. At 0.184 cm³ cm⁻³ initial water content, the reduction of, water in the first half (hot side) of the column and consequent increase in the second half (cool side) was greater than that in the columns with initial water contents of 0.075 and 0.280 cm³ cm⁻³. When the temperature gradient was increased from 0.5 to 1°C cm⁻¹ the reduction of water in the first half and consequent increase in the second half of the column increased at all initial water contents. The net water flux was maximum in 0–36 hours interval, less in 36–76 hours interval and least in 76–150 hours interval at all the initial moisture and temperature gradients. Also, the flux was always maximum at 0.184 cm³ cm⁻³.