"Irrigation" is a very important chapter of the Agriculture and Rural Development section of the NABARD Grade-A Exam. In this article, we have discussed the Subsurface method of irrigation. Read this post now to enhance your NABARD Grade A Exam preparation!
- As the name suggests, in Subsurface Irrigation, water is applied below the ground surface.
- The main aim of subsurface irrigation is to reduce evaporation loss and maintain the artificial water table near the crop's root zone.
- This is done by creating and maintaining an artificial water table at some depth, usually 30 to 75 cm, below the ground surface.
- Water is applied through the network of perforated pipes or underground distribution system consisting of properly designed main field ditches, laterals, laid 15 to 30 m apart.
- Water required for the underground distribution system may be obtained from wells, streams, lakes, etc.
- Water is introduced into the soil profile through open ditches, mole drains, or tile drains. Open ditches are preferred over mole drains or tile drains because they are relatively inexpensive and suitable for all types of soils. Tiles and mole drains are considered suitable only for organic soils.
- The artificial water table created helps moisture move upwards towards the land surface through capillary action to meet the requirements of the crops in plant roots.
- It entails minimum evaporation loss and surface waste. The irrigation water is essentially required to be of good quality to prevent excessive soil salinity.
- The flow rate in supply ditches is required to be low to prevent waterlogging of the field.
- Sub-surface irrigation requires little field preparation and labor.
- The use of sub-irrigation is limited because it requires certain soil conditions, that is, the soil is permeable in the root zone, underlain by an impervious horizon or high-water table.
Essential Requirements for Irrigation
The essential requirements for successful sub-surface irrigation are-
- Good Quality water should be available throughout the growth period of the crop to prevent excessive soil salinity.
- Fields must be nearly level and smooth.
- Availability of a layer of permeable soil such as sandy loam or loam immediately below the surface soil to permit free and rapid movement of water laterally and vertically.
- Availability of adequate outlet for drainage of the area so irrigated, particularly in humid areas.
- The subsoil water table is within 2 to 3 m below the ground surface, & Topographical conditions are uniform.
- The soil is capable of lifting moisture from the water table to the root zone.
- The efficiency of water use depends on soil characteristics, topography, operation, and maintenance management.
- In a good system, the efficiency of subsurface irrigation is 70-75 percent.
Suitability - It is mainly suitable for the high-temperature area where ET losses are very high wherein controlling and maintenance of surface water and application is very difficult.
If you are aiming to crack NABARD Grade-A, then join the Online Classroom Program where you will get:
- Live Courses by Top Faculty
- Daily Study Plan
- Comprehensive Study Material
- Latest Pattern Test Series
- Complete Doubt Resolution
- Regular Assessments with Report Card
Why BYJU'S Exam Prep Test Series?
- Unlimited access to 18+ Bank and Insurance Exam mock tests
- Mock Tests designed by Exam Experts.
- Detailed Performance Analysis.
Download the BYJU’S Exam Prep App Now.
The most comprehensive exam prep app.