Transport and Evaporation of Water from Soil Columns under Conditions of High Water-Table

Soil-water evaporation under 10, 30, 50, 70 and 85 cm water-table depths was studied in Haldi loam soil of Pantnagar. Evaporation potential of 2.3 cm/day was applied by passing heated air of constant temperature and speed over the soil surface. Under steady state temperature conditions the maximum temperature zone occurred at 5 cm depth causing a temperature gradient both towards the surface and down below. These temperature fields resulted in thermal moisture transfer both in vapour and liquid phases in the direction of decrease in temperature gradient. The thermally induced vapour flow of moisture was 0.02 cm/day whereas liquid phase transport ranged from 0.12 to 0.57 cm/day downwards, and from 0.047 to 1.120 cm/day, towards the surface, from the maximum temperature zone under different water-table depths. Thermal vapour flow increased when the water content in the soil was decreased.