Evaporation and Salinization in Layered Soils in the Presence of Water-table

In a study conducted to evaluate the effect of water-table depths on evaporation and salinization in soil columns, with increase in the water-table depth, steady state evaporation did not change in uniform columns, whereas it decreased markedly in layered columns. Steady state evaporation rate decreased in layered columns with water-table at 55, 65 and 75 cm by 58, 85 and 100 per cent compared to that in corresponding uniform columns. Increased resistance to hydraulic conductivity of the profile as a result of the presence of interlayer contact zones in the layered case is attributed for reduced upward water flux. Although suction difference across both the interlayer contact zones increased with increase in the water-table depth it increased by about 4, 65, 439 times across the upper interlayer contact zone as much as across the lower interlayer contact zone in 55, 65 and 75 cm long soil columns, respectively. Soil salinity decreased in layered columns of 55, 65 and 75 cm water-table depths by 38, 50 and 83 per cent compared to that in corresponding uniform column. This study indicates economic utilization of surface heterogeneities generally present in these soils for managing salt-affected and waterlogged soils.