Irrigation essentially means the watering of land to make it ready for agricultural purposes. An irrigation system is the supplying of water via artificial canals and channels to growing plants and crops in a field.
Water is vital for the growth of plants. There can be no plants or crops if they do not have access to water in some form. It is, therefore, crucial to supply water to crops and plants, periodically and as per their requirement. So irrigation is this periodic and appropriate supply of water to plants. The water for this irrigation comes from various sources such as wells, ponds, rivers, dams, reservoirs, rainfall etc.
Importance of Irrigation(method)
Irrigation is necessary for agriculture and farming due to the following reasons:
- Plants absorb minerals and nutrients from the soil via their roots. These minerals are dissolved in the water present in the soil. Then the water transports these nutrients to all parts of the plant, enabling growth and photosynthesis.
- Irrigation provides the moisture that is crucial during the germination phase of the plant’s life cycle.
- Irrigation also makes the soil more fertile (by adding moisture to it) and easier to plough.
- Proper irrigation also increases yield from the farm
Traditional Methods of Irrigation method
These are the methods of irrigation that were used in the earlier years. Even today some small farms in rural areas adopt these. Although they are cheaper than the modern methods, they are not nearly as efficient. They require human or animal labour to function. Some of these methods are,
1. Moat Irrigation method
Also called the pulley system, it involves pulling up water from a well or other such source to irrigate the land. It is an extremely time consuming and labour intensive system, but it is very cost efficient. Also, wastage of water is avoided when using a moat system of irrigation.
2. Chain pump Irrigation method
A chain pump consists of two large wheels connected by a chain. There are buckets attached to the chain. One part of the chain dips into the water source. As the wheel turns, the bucket picks up water. The chain later lifts them to the upper wheel where the water gets deposited into a source. And the empty bucket gets carried back down.
3. Dhekli Irrigation method
It is a system of drawing water from a well or such similar source. Here we tie a rope and bucket to a pole. At the other end, we tie a heavy stick or any other object as a counterbalance. And we use this pole to draw up water.
4. Rahat Irrigation method
So Rahat system of irrigation uses animal labour. Above the well, we tie a large wheel. An ox or cow would turn the wheel to draw the water from the well.
Modern Irrigation method
Surface irrigation method
Surface irrigation stands for a large group of irrigation methods in which water is distributed by gravity over the surface of the field. The three most common methods are basin irrigation, border irrigation and furrow irrigation.
Border Irrigation method
In many circumstances, border irrigation can be viewed as an expansion of basin irrigation to include long rectangular or contoured field shapes, longitudinal but no lateral slope, and free draining or blocked conditions at the lower end.In border irrigation, a field is divided into strips separated by border ridges running down the slope of the field. The width of the stripes is usually from 20 to 100 feet. The area between the ridges is flooded during irrigation. Border irrigation is used for tree crops and for crops as alfalfa (Medicago sativa) and small grains.
Basin Irrigation method
Basin irrigation is the most common form of surface irrigation, particularly in regions with layouts of small fields. If a field is level in all directions, is encompassed by a dyke to prevent runoff, and provides an undirected flow of water onto the field, it is herein called a basin.
Furrow Irrigation method
An alternative to flooding the entire field surface is to construct small channels along the primary direction of water movement. Water introduced in these furrows infiltrates through the wetted perimeter and moves vertically and laterally thereafter to refill the soil. Furrows can be used in conjunction with basins and borders to overcome topographical variation and crusting. Furrows are well adapted to row crops and orchards or vineyards.
Subsurface irrigation method
Subsurface irrigation, also designated as sub irrigation, involve irrigation to crops by applying water from beneath the soil surface either by constructing trenches or installing underground perforated pipe lines or tile lines. Water is discharged into trenches and allowed to stand during the whole period of irrigation for lateral and upward movement of water by capillarity to the soil between trenches.
Sprinkler Irrigation method
Sprinkler Irrigation is a method of applying irrigation water which is similar to rainfall. Water is distributed through a system of pipes usually by pumping. It is then sprayed into the air and irrigated entire soil surface through spray heads so that it breaks up into small water drops which fall to the ground.
Sprinklers provide efficient coverage for small to large areas and are suitable for use on all types of properties. It is also adaptable to nearly all irrigable soils since sprinklers are available in a wide range of discharge capacity.
Drip irrigation method
Drip irrigation is a method of controlled irrigation in which water is slowly delivered to the root system of multiple plants. In this method water is either dripped onto the soil surface above the roots, or directly to the root zone. It is often a method chosen over surface irrigation because it helps to reduce water evaporation.