Irrigation | Definition, Advantages, Disadvantages, Types of Irrigation

Irrigation | Definition, Advantages, Disadvantages, Types of Irrigation

Irrigation:-

It is defined as the science of the artificial application of water to the field according to the requirement of the crop to its full-fledged nourishment throughout the crop period.

Advantages of Irrigation:-

Following are the advantages of irrigation:-

1. Increase in food production:- Irrigation help in increasing crop yield and hence to attain self- sufficiency in food.

2. Optimum benefits:- Optimum utilisation of water is made possible by irrigation. By optimum utilisation, obtaining maximum crop yield with the required amount of water.

3. Elimination of mixed cropping:- Mixed cropping is generally not acceptable, because different crops require different types of field requirements and different types of watering etc.

4. General Prosperity:- Revenue returns with a well-developed irrigation system are sometimes quite high, and helps in all-around the development of the country and prosperity of the entire nation and community.

5. Generation of Hydro-electric power:- Canal outlets from dams and canal falls on irrigation canals can be used for power generation.

6. Domestic water supply:- Development of irrigation facilities in an area helps in expanding the water supply in nearby villages and towns.

7. Facilities of communications:- Irrigations channels are generally provided with embankments and inspection road, which used as communication.

8. Inland navigation:- Sometimes large irrigation canals can be used and developed for navigation purposes.

9. Afforestation:- Trees are generally grown along the bank of the channels. Which increase the timber wealth of the country and also helps in reducing soil erosion and air pollution.   

Disadvantages of Irrigation:-

Following are the disadvantages of irrigation:-

1. Irrigation may contribute in various ways to the problem of water pollution. One of these is seepage into the groundwater of the nitrates that have been applied to the soil as fertilizer.

2. Over irrigation may lead to waterlogging and may reduce crop yield.

3. Irrigation mar result in colder damper climate, resulting in marshy land, and breeding of mosquitoes, causing an outbreak of diseases.

4. Supplying of irrigation water is complex and expensive in itself.  

                                                           

Types of Irrigation:-   

Irrigation may be classified as:-

1. Surface Irrigation:- It can be further classified as-

      A) Flow Irrigation

      B) Lift Irrigation

A) Flow Irrigation:- When the water is available at a higher level and it is supplied to lower level by the mere action of gravity, then it is called flow irrigation.

B) Lift Irrigation:- when water is lifted up by some mechanical or manual means, such as by pumps etc and then supplied for irrigation, then it is called lift irrigation.

Flow Irrigation can be further sub-divided into:-

       I) Perennial Irrigation

       II) Flood Irrigation

I) Perennial Irrigation:- In a perennial system of irrigation, constant and continuous water supply is assured to the crops, throughout the crop period.

II) Flood Irrigation:- In this method of irrigation, the soil is kept submerged and thoroughly flooded with water.

Perennial Irrigation may be-

       a) Direct Irrigation

       b) Storage Irrigation

a) Direct Irrigation:- When irrigation is done by diverting the river runoff into the main canal by constructing a diversion weir or barrage across the river, then it is called direct irrigation.

b) Storage Irrigation:- When a dam is constructed across a river to store water during monsoon, so as to supply in the off taking channel during the period of low flow, then it is called storage irrigation.

2. Sub-surface Irrigation:- In this type of irrigation, water does not supply to the surface of soil directly. The underground water full-fill the water requirement of plant roots by capillarity.

Sub-surface Irrigation may be divided into two types-

      A) Natural Sub-surface Irrigation

      B) Artificial Sub-surface Irrigation

A) Natural Sub-surface Irrigation:- Leakage water from channels goes underground and during passage through the sub-soil, it may irrigate crops, sown on lower lands, by capillarity.

B) Artificial Sub-surface Irrigation:- In this irrigation system, the system of open jointed drains is artificially laid below the soil, so as to supply water to the crops by capillarity.

Advantages of Lift Irrigation Over Flow Irrigation:-

Following are the advantage of lift irrigation over flow irrigation-

1. Lift irrigation can be set up directly on the farm at any time with small investment.

2. Water can be supplied to the required depth at the time of irrigation.

3. There are no or negligible evaporation losses and water pollution.

4. It prevents waterlogging.

5. It has a high irrigation efficiency.

6. It improves the method of irrigation.

7. Cash crops can be grown easily.

8. The land where canal water cannot reach, irrigate easily.

9. Irrigation is possible even in a drought year.

10. With good water management, high yield can be obtained.