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In all these four forces, the gravitational and capillary forces are important because their significance in the movement of water in the soil is more. Summary of Cultivation of Rabi Cereal Crops the situation is only observed in only saline soil which has excessive salts. (4) Osmotic pressure:The movement of water takes place due to difference in osmotic pressure of the soil solution. (3) vapour tension:If the soil is not water logged, the movement of water vapour may take place to a very little extent from soil layers which gets more heated towards the cooler soil layers particularly when difference between their temperatures are very wide. The surface or capillary tension is responsible for the capillary movement of water to all directions from low tension to high tension. Once the flow due to gravitational force has ceased the water moves in the form of thin or capillary film from a wet region to a dry region through finer or micro-pores. The movement of water under unsaturated soil conditions is due to force of surface tension. (2) Capillary force or capillary tension:In the soil, water is held by the forces of surface in the capillary spaces and around the soil particles. macro-pores serve as the main channels for gravitational flow. (1) Gravitational force or gravity tension: The flow of water due to gravity is very marked when the soil is in saturated condition and generally, the direction of such flow is downward although a little lateral flow takes place. The forces which cause the water movement in soil are: Forces Causing Water Movement and Retention of Water in Soil