Last reviewed 16 Sept 2026 · 7 min read
Irrigation systems
| Classification | Types |
|---|---|
| Source of supply | Surface water (rivers, reservoirs, tanks); groundwater (wells, tube wells) |
| Method of conveyance | Flow irrigation — water flows by gravity to the fields; lift irrigation — water lifted by pumps or other devices |
| Reliability of supply | Perennial irrigation — assured supply throughout the crop period (from storage or perennial rivers); inundation irrigation — canals run only during high river stages in floods (unreliable) |
| Type of works | Storage (reservoir) irrigation; diversion (direct) irrigation from weirs and barrages |
| Scale (Indian classification by CCA) | Major projects — CCA above 10 000 ha; medium — 2000 to 10 000 ha; minor — up to 2000 ha |
Tank irrigation — small storages (common in southern India); well irrigation — open wells and tube wells, the largest source of irrigation in India today.
Surface irrigation methods
In surface methods water is applied over the soil surface and flows by gravity.
Uncontrolled (wild) flooding
Water is spread over the land without control of depth or flow — cheap but wasteful and non-uniform; used where water is plentiful and land relatively flat.
Border strip method
The field is divided into long, narrow strips (commonly 3–20 m wide and 60–300 m long) separated by low ridges (borders). Water released at the upper end flows down the gentle slope as a sheet.
- Suited to close-growing crops (wheat, fodder, pastures) and medium-to-low infiltration soils on uniform slopes.
- Needs precise land levelling along the length.
For supply , strip area , depth of water flowing over the strip and infiltration capacity (consistent units):
Maximum area that can be irrigated: (when infiltration equals supply).
Check basin method
The field is divided into nearly level plots (checks) surrounded by low bunds; water is ponded to the required depth. Suited to rice, permeable and heavy soils, and flat land.
Basin (ring) method
Circular or square basins around individual plants — orchards and trees; water is fed through a supply channel into each basin.
Furrow method
Water runs in small channels (furrows) between crop rows; only part of the surface is wetted (about one-fifth to one-half).
- Suited to row crops — maize, cotton, sugarcane, potatoes, vegetables.
- Less evaporation loss and less puddling/crusting than flooding.
- Corrugation method — small closely spaced furrows for close-growing crops on uneven land.
- Contour furrows on sloping land.
Subsurface irrigation
Water is applied below the surface to the root zone by raising the water table or through buried perforated pipes.
- Natural — seepage from canals or a naturally high water table maintained by controlled drainage.
- Artificial — open-jointed or perforated pipes laid below the root zone.
- Needs a permeable top layer over an impervious layer; little evaporation; high cost; risk of salt accumulation.
Sprinkler irrigation
Water is sprayed into the air under pressure and falls on the crop like rain.
Types
- Rotating head (rotary) sprinklers — nozzles on rotating heads cover circles; most common.
- Perforated pipe system — pipes with small holes; low pressure, small areas (nurseries, gardens).
- By portability: portable, semi-portable, semi-permanent and permanent (solid-set) systems; centre-pivot and travelling gun systems for large areas.
Components
Pump unit, main line and sub-mains, laterals, risers and sprinkler heads, pressure gauge, valves, filters, fertiliser applicator.
= sprinkler discharge; = spacing of sprinklers along the lateral; = spacing of laterals along the main. The application rate must not exceed the infiltration rate of the soil (to avoid runoff).
Merits: suited to undulating land and shallow or sandy soils where levelling is difficult; saves land used by channels and bunds; uniform application and higher efficiency than surface methods; light, frequent irrigation possible; fertilisers and pesticides can be applied; frost protection.
Limitations: high initial and energy cost; wind distorts distribution; evaporation loss in hot dry climates; not suited to very heavy soils with low infiltration or to crops sensitive to wet foliage; saline water can scorch leaves.
Drip (trickle) irrigation
Water is applied drop by drop, at low rates and low pressure, directly to the root zone of each plant through emitters.
Components
- Head unit — pump, filters (sand/media filter for organic matter, screen or disc filter for fine particles, hydrocyclone for sand), fertiliser tank or venturi injector (fertigation), pressure regulator, valves, non-return valve.
- Main line and sub-main (PVC/HDPE).
- Laterals (LDPE), laid along plant rows.
- Emitters (drippers) — online or inline; pressure-compensating types give uniform discharge on slopes; typical discharge a few litres per hour.
- Flush valves, air-release valves.
Variants: micro-sprinklers, bubblers (for trees), subsurface drip.
Water requirement per plant
( = crop evapotranspiration in mm/day, = area per plant in m², = wetted-area/canopy factor.) Operating time = ÷ (number of emitters × emitter discharge).
Merits: highest water-use efficiency (very little evaporation, runoff or deep percolation); water saving and higher yields; fertigation — nutrients applied precisely; less weed growth (dry inter-row space); works on undulating land and poor soils; saline water can be used with care (continuous moisture keeps salts at the wetting front edge); lower labour and energy (low pressure).
Limitations: high initial cost; clogging of emitters (needs filtration and periodic acid/chlorine treatment); salt accumulation at the periphery of the wetted zone; damage by rodents; needs technical skill and maintenance; limited to high-value row crops, orchards, vegetables, sugarcane, plantations.
Comparison of methods
| Aspect | Surface | Sprinkler | Drip |
|---|---|---|---|
| Typical efficiency (indicative) | Low to moderate | Moderate to high | Highest |
| Land levelling | Required | Not required | Not required |
| Initial cost | Low | High | Highest |
| Energy/pressure | Nil (gravity) | High | Low |
| Suitable crops | Most field crops, rice | Close-growing crops, vegetables | Row crops, orchards, vegetables |
| Wind effect | None | Significant | None |
| Soil suitability | Medium to heavy soils | Light and undulating soils | All, including poor soils |
In India, micro-irrigation (drip and sprinkler) is promoted under the "Per Drop More Crop" component of the Pradhan Mantri Krishi Sinchayee Yojana (PMKSY).
Worked examples
A border strip is supplied with 0.04 m³/s. Infiltration capacity is 5 cm/h and the average depth of flow over the strip is 10 cm. Find the time to irrigate 2000 m², and the maximum area that can be irrigated.
Solution. m³/h; m/h; m³/h
Sprinklers discharging 1.2 m³/h each are spaced 12 m apart on laterals that are 18 m apart. Find the application rate. Is it acceptable for a soil with infiltration rate 8 mm/h?
Solution. < 8 mm/h → acceptable (no runoff).
An orchard has trees at 3 m × 3 m. Crop ET is 6 mm/day, wetted-area factor 0.5, and each tree has 2 drippers of 4 L/h. Find the daily volume per tree and the operating time.
Solution. Time per day
Frequently tested points
- Flow vs lift; perennial vs inundation; storage vs diversion.
- Indian scale: major > 10 000 ha CCA; medium 2000–10 000 ha; minor < 2000 ha.
- Border strip: close-growing crops; ; .
- Check basin for rice; ring basin for orchards; furrow for row crops (cotton, sugarcane, maize).
- Sprinkler: undulating/sandy land; application rate ≤ infiltration rate; wind affects uniformity.
- Drip: highest efficiency, fertigation, filters prevent clogging; salts accumulate at wetting-front periphery.
- Micro-irrigation promoted under PMKSY "Per Drop More Crop".
- Recommending sprinklers for very windy areas or rice fields.
- Allowing sprinkler application rate to exceed infiltration rate.
- Assuming drip irrigation eliminates salinity problems entirely.
- Irrigation systems are classified by source, conveyance, reliability, works and scale.
- Surface methods — border, check basin, basin and furrow — suit different crops, soils and slopes.
- Subsurface irrigation applies water below the surface under special soil conditions.
- Sprinklers suit undulating and light soils; application rate must not exceed infiltration.
- Drip irrigation gives the highest efficiency and fertigation but needs filtration and investment.