The manner in which water is applied to the land is commonly referred to as method of irrigation. These methods are adopted to apply irrigation water to the crop depending on the landscape, amount of water and equipment available, the crop and method of cultivation of crop. The main aim of these methods is to store water in the effective root zone uniformly and in maximum quantity ensuring minimum water loss and to get optimum yield.
Various methods of irrigation are:
1. Surface method
2. Sub-surface method
3. Sprinkler method
4. Drip method
In the surface system, water flows by gravity either through furrows basins or borders. In this type, water loss by conveyance and deep percolation is heavy and the efficiency of irrigation is only 40 to 50% at field level. Efficiency can be improved by lining the canal and by proper leveling of the field.
The method is suitable for specific types of soils. Evaporation and other losses are reduced considerably since water is applied below the surface through porous pipes.
Water is applied in the form of rain. Water is conveyed through pipes and sprayed though sprinklers. This method is most suited for steep sloppy and sandy soils.
Drip irrigation is adopted in water scarce areas for conserving water. In this method, water is applied in drops around the root zone through a pipeline with appropriate drippers.
The common methods of irrigation are indicated schematically as follows:
Whatever be the method of irrigation, it is necessary to design the system for the most efficient use of water by the crop.
Surface method of irrigation
Surface irrigation (gravity irrigation) is the most ancient method of irrigation and this method still holds good for more then 95 per cent of the irrigated area in the world. It can be defined as the process of introducing a stream of water at the head of a field and allowing gravity and