Drainage and capillary rise components in water balance of alluvial soils

The flux of water at the bottom of the soil profile is an important element in many drainage models. This downward seepage or capillary rise was measured using lysimeters in field conditions during 4 years (1972–1975). During the growing seasons, the capillary rise was equal to 90–150 mm for Aquepts Inceptisols and 60–130 mm for Aquepts Histosols. For the growing season the cumulative net capillary supply and cumulative precipitation are such, that in a dry year the capillary supply can be 40–50% of the total supply for Histosols, but close to zero for some Inceptisols. Vertical movement of water is upward in the Histosols, but slowly downward or zero in the Inceptisols. The measured values gave an indication how to determine the water exchange between the soil profile and the subsoil parent material for alluvial deposits in deltaic areas.