Water is necessary for plant growth and maturity. Irrigation, the artificial means of supplying water, becomes necessary for plant growth in the following cases.
- If rainfall is less than demand of plants, irrigation is necessary to fulfill the water requirement of plants.
- Difference in water holding capacity of the soil plays important role in the Necessity of Irrigation supply. For example, sandy soil requires frequent irrigation than clay soil.
- If rainfall is sufficient but spatial distribution is not as per requirement, irrigation becomes necessary.
- If rainfall is sufficient, spatial distribution is also good but temporal distribution is not as per requirement, irrigation water is necessary for plants.
- Advanced scientific development like High Yielding Varieties Seeds (HYV) demands irrigation. Actually irrigation is the most important input for HYV.