Water is an essential requirement for growing crops. Right from seed germination to the proper growth of the crop, water is required at all stages. But the availability of water is not always easy in every crop field. In such cases, methods of irrigation come to our rescue. Irrigation contributes to supplying water to the soil for the cause of high crop production. It is done to replace rainwater with an additional source of water. It is used in dry areas and also during periods of inadequate rainfall.  Effective irrigation systems are needed to help in the growth of agricultural crops.

What is Irrigation?

Irrigation is how a controlled amount of water is supplied to plants at regular intervals for agriculture. It assists in growing crops, maintaining landscapes, and revegetation disturbed soils in dry areas and during periods of inadequate rainfall.

Sources of Irrigation

Rain is the natural source of irrigation. Since the rainfall is not caused throughout the year, the rainwater is collected in wells, lakes, ponds, etc., naturally can be used for irrigation purposes. Irrigation depends on different sources such as wells, tube wells, rivers, ponds, lakes, canals, dams, etc.

Methods of Irrigation

Irrigation methods are divided into two categories based on science and technology. The two irrigation methods are the traditional method of irrigation and the modern method of irrigation.

1. Traditional Method of Irrigation: Traditional methods of irrigation are less effective. This method is followed in the olden days by using wood, ropes, sticks, clay, for the construction of these setups. As the water retains in the reservoirs like wells, ponds, lakes, etc., less soil erosion is caused. Farmers use animals or humans to pull the underground water from different sources. The few traditional methods are listed below:

(a) Moat/Pulley System: The waters are pulled out from the underground with the help of a pulley. The pulley can be moved in several ways to carry the bucket or pot of water to different places in the field, but this type of irrigation requires human labour.

(b) Chain Pump: The chain pump is a type of water pump in which several circular discs are positioned on a long chain on a wooden wheel. The ground part of the wheel is partially immersed in the water source like a pond, lake, river, etc. As the wheel is turned, the connected cans dip into the water source and lift up water. The chain then brings them to the upper wheel, taking them out from the pool again transferring them. The chain then carries the empty cans back down to be refilled, and the process continues.

(c) Dhekli: In this system, rope and cans are joined to poles to obtain water from wells. They connect rope and cans on one end of a heavy stick and a heavy counterweight at the other end to lift water.

(d) Rahat: In this method, water is drawn out of wells by animals like cows, buffalo, oxen, etc., which are connected to the wheel. Animals move and rotate the wheel lead to draw the water from the well.

2. Modern Method of Irrigation: Modern methods of irrigation are more advanced to grow crops in a short period of time without waiting for natural rainfall. The most commonly used modern methods of irrigation are drip irrigation and sprinkler irrigation.

Flowchart of Irrigation Methods

Types of Irrigation

1. Surface Irrigation: Surface irrigation is a method where the water is distributed over the soil surface by gravity. It is the most common form of irrigation throughout the world.

Fig: Surface Irrigation

(a) Wild Flood Irrigation: Wild flood irrigation, the water is managed directly to the field by canal or pipe and flows over the soil surface through the crops.
(b) Basin Irrigation: Basin irrigation is a rare form of surface irrigation. This method of irrigation requires a levelled soil surface and a narrow elevation about \(15 – 50\,\,{\rm{cm}}\) high on all sides of the field, which serves as a basin.
(c) Border Irrigation: Border irrigation is performed on the basis of basin irrigation. Here, the direct water is transported to the land through wide borders.
(d) Furrow Irrigation: Furrow irrigation is conducted by creating small parallel channels along the field length in the direction of the predominant slope. Water is applied to the top end of each furrow and flows down the field under the influence of gravity.

2. Drip Irrigation: Drip irrigation is practised in order to prevent wastage of water. In this method, water is allowed to fall drop by drop at the roots of the plants. Drip irrigation is rarely used since maintenance and care is highly required. 

3. Sprinkler/Spray Irrigation: Sprinkler irrigation technique, the water is sprinkled into the air and allowed to fall on the ground surface just like rainfall. The spray is done by the flow of water under pressure through small purifiers or nozzles.

Advantages of Irrigation

1. Irrigation removes the deficiency caused due to inadequate rainfall.
2. It improves the yield of crops.
3. Irrigation increases the income of farmers and labour employment.
4. It helps in groundwater storage.
5. Irrigation increases the value of land and the cost of living and growing a number of crops during a year.
6. It helps in the elimination of mixed cropping.
7. Due to irrigation plants get the right amount of water for growth even if there is an absence of rainfall.
8. Growing of perennial crops.
9. Irrigations help in controlling the water supply.
10. Commercial crops can get enough water for growth.

Disadvantages of Irrigation

1. Immersing of agricultural land due to rise in the water table. (waterlogging)
2. Salinity and alkalinity of land get increased.
3. Loss of aeration in the soil.
4. Pollution of underground water.
5. The initial cost of some irrigation methods is very high.

Summary

In the present world, farmers are not much dependent on the rain to grow their crops. Humans used to take the help of animals in the olden days to irrigate the land. Irrigation is an important element for growing crops. Now there are many modern irrigation practices that are adopted by the farmers to grow their annual crops. Due to irrigation practices, the rise in the water table and wastage of water is reduced. moat, chain pump, rahat, etc., are few traditional techniques of irrigation that are very time-consuming, and manual labour is required.

When science and technology advanced, modern irrigation systems like drip irrigation, sprinkler irrigation, surface irrigation, etc., came into existence. We should always learn to save natural resources and never waste a precious resource like water.

FAQs

Q.1. What do you mean by irrigation?
Ans: Irrigation is how a controlled amount of water is supplied to plants at regular intervals for agriculture. It assists in growing crops, maintaining landscapes, and revegetation disturbed soils in dry areas and during periods of inadequate rainfall.

Q.2. What are 3 types of irrigation?
Ans: 1. Surface irrigation
2. Drip irrigation
3. Sprinkler irrigation

Q.3. What are the advantages of irrigation?
Ans: 1. Irrigation removes the deficiency caused due to inadequate rainfall.
2. It improves the yield of crops.
3. Irrigation increases the income of farmers and labour employment.
4. It helps in groundwater storage.
5. Irrigation increases the value of land and the cost of living and growing a number of crops during a year.

Q.4. What are the negative effects of irrigation?
Ans: 1. Immersing of agricultural land due to rising in the water table. (waterlogging)
2. Salinity and alkalinity of land get increased.
3. Loss of aeration in the soil.

Q.5. What is the surface irrigation method?
Ans: Surface irrigation is a method where the water is distributed over the soil surface by gravity. It is the most common form of irrigation throughout the world.

We hope this detailed article on Irrigation helps you in your preparation. If you get stuck do let us know in the comments section below and we will get back to you at the earliest.