the process of removing excess water from an agricultural land is referred to as

Drainage is the process of removing excess water from agricultural land, either through natural channels or through artificial structures such as open ditches, subsurface pipes, or tile drains. Proper drainage prevents waterlogging, which can suffocate plant roots by cutting off their oxygen supply.

Percolation is the downward movement of water through soil pore spaces under the influence of gravity. It is a natural physical process, not a deliberate removal technique. Infiltration is the entry of water from the soil surface into the soil profile - the first stage of water entering the ground. Dredging is the excavation of sediment from the bottom of rivers, harbours, or canals; it is a water-body maintenance operation, not a farmland water-removal practice.

Examination tip: Keep the sequence clear - rainwater first infiltrates the surface, then percolates downward through the profile, and if the soil becomes saturated, drainage is needed to remove the excess.