The type of soil, the topography of the land, the water supply and the crop to be irrigated determine the right method of irrigation to be used. Whatever be the method of irrigation, the design of the system is necessary for the most efficient use of water by the crop. In the surface method of irrigation, water is applied directly to the soil surface from a channel at the upper reach of the field.
Water may be distributed to the crops in border strips, check basins or furrows. Two general requirements of prime importance to obtain high efficiency in surface method of irrigation are properly constructed. Water distribution system will provide adequate control of water to the fields and proper land preparation to permit uniform distribution of water over the field. In the sprinkler method of irrigation, water is sprayed into the air and allowed to fall on the ground surface somewhat resembling rainfall. WIth careful selection of nozzle sizes, operating pressures and sprinkler spacing, the amount of irrigation water required to refill the crop root zone can be applied nearly at a rate to suit the infiltration rate of the soil, thereby obtaining efficient irrigation. The drip irrigation method is becoming increasingly popular in areas with water scarcity and salt problem. The plants are watered with the help of emitters or drippers frequently and with a volume of water approaching the consumptive use of the plants where conventional losses such deep percolation, runoff and soil water evaporation are minimised.