2. Irrigation
• Irrigation is defined as the artificial application of water to
the soil for the purpose of crop production in supplement to
rainfall and ground water contribution.
3. Irrigation Management
• Management of water based on the soil and crop
environment to obtain better yield by efficient use of
water without any damage to the environment.
• Irrigation management is a complex process of art and
science involving application of water from source
to crop field. The source may be a river or a well or
a canal or a tank or a lake or a pond.
4. Sources of water
• Rainfall is the ultimate source of all kind of water.
• Based on its sources of availability it can be classified as
surface water and subsurface water.
5. Surface water
• Surface water includes precipitation (including rainfall and
dew) water available from river, tank, pond, Lake etc.
8. Project Capital Command Area
Major more than 50 million
Rupees
more than 10,000
hectares
Medium 2.5 million to 50
million Rupees
2000 – 10,000
hectares
Minor less than 2.5 million
Rupees
2,000 hectares
10. Surface irrigation
• Surface irrigation is one of the simplest and widely adopted
methods, especially in India.
• The water is made to flow on the soil surface or in the
furrow.
• Advantage: A farmer needs to invest less
• Disadvantage: It requires more attention; soil becomes
more puddle and bake; more losses of water through
seepage and over irrigation; uneven distribution of water
and farm machinery cannot conveniently cross at different
point.
13. Flooding
• In this method water flows from the ditch directly to the field
without much control on either side of the flow. It covers the
entire field and moves almost unguided.
• The rate of advancing front is controlled by the topography of the
field.
• Land leveling is not precisely followed.
• Uneven distribution of water and low water application
efficiency are the common drawbacks of this method. But the
method is easy and inexpensive.
• Close growing crops are generally irrigated by this method.
15. Border irrigation
• Border irrigation can be viewed as an extension of basin irrigation
• The land is divided into number of long parallel strips called borders.
These borders are separated by low ridges.
• The border strip has a uniform gentle slope in the direction of irrigation.
• Each strip is irrigated independently by turning the water in the upper
end.
• The water spreads and flows down the strip in a sheet confined by the
border ridges.
• Border slopes should be uniform, with minimum slope of 0.05% to
provide adequate drainage and a maximum slope of 2% to limit problems
of soil erosion.
16. Suitability
• Suitable to soils having moderately low to moderately high
infiltration rates.
• It is not used in coarse sandy soils that have very high
infiltration rates and also in heavy soils having very low
infiltration rate.
• Suitable to irrigate all close growing crops like wheat,
barley, fodder crops and legumes and not suitable for rice.
18. Basin Irrigation
• A basin is usually made for one tree sapling.
• Basins are made longer and wider as saplings grow in size.
• The land inside basins is flat with the base area of trees kept little
raised so that the sapling stems do not come in direct contact with
water.
• Water is supplied through laterals and each basin may be connected
with another one by a small furrow to get the water supply.
19.
20. Check basin irrigation
• It is the most common surface irrigation method.
• Here, the field is divided into smaller unit areas so that each has a nearly
level surface.
• Bunds or ridges are constructed around the area forming basins within
which the irrigation water can be controlled.
• The water applied to a desired depth can be retained until it infiltrates into
the soil.
• The size of the basin varies from 10 m2 to 25 m2 depending upon soil type,
topography, stream size and crop.
21. Adaptability
• Small gentle and uniform land slopes and soils having moderate to
low infiltration rates.
• Adapted to grain and fodder crops in heavy soils and suitable to
permeable soils.
23. Ring Irrigation
• Ring method consists of irrigating fruit trees in orchards by constructing
circular trenches around trees.
• Ring trenches are smaller in both depth and width around small trees and
are larger around bigger trees.
• Usually, a ring is laid out at the periphery of the tree canopy.
• The ring trenches are usually made 30 to 50 cm wide and narrow furrows.
• Laterals pass through a set of two rows of trees supplying water into rings
on both sides.
• Water supply process is essentially the same as with the basin irrigation.
• Water in desired quantity is allowed to stand in the trenches for infiltration.
25. Furrow irrigation
• It is used for row crops.
• The furrows are formed between crop rows.
• The dimension of furrows depend on the crop grown, equipment used and
soil type.
• Water is applied by small running streams in furrows between the crop
rows.
• Water infiltrates into soil and spreads laterally to wet the area between the
furrows.
• In heavy soils, furrows can be used to dispose the excess water.
32. Alternate furrow irrigation
• It is not an irrigation layout but a technique for water
saving.
• Water is applied in alternate furrows.
• Example: During first irrigation if the even numbers
of furrows are irrigated, during next irrigation, the odd
number of furrows will be irrigated.
33. Skip furrow irrigation
• They are normally adopted during the period of water scarcity
and to accommodate intercrops.
• In the skip furrow irrigation, a set of furrows are completely
skipped out from irrigation permanently.
• The skipped furrow will be utilized for raising intercrop.
• The system ensures water saving of 30-35 per cent.
• By this method, the available water is economically used
without much field reduction.
35. Surge irrigation
• Surge irrigation is the application of water into the furrows
intermittently in a series of relatively short ON and OFF times of
irrigation cycle.
• It has been found that intermittent application of water reduces the
infiltration rate over surges thereby the waterfront advances
quickly. Hence, reduced net irrigation water requirement.
• This also results in more uniform soil moisture distribution and
storage in the crop root zone compared to continuous flow.
• The irrigation efficiency is in between 85 and 90%
37. SUB-SURFACE IRRIGATION
• In subsurface irrigation, water is applied beneath the ground by
creating and maintaining an artificial water table at some depth, usually
30-75 cm below the ground surface.
• Moisture moves upwards towards the land surface through capillary
action.
• Water is applied through underground field trenches laid 15-30 m
apart.
• Open ditches are preferred because they are relatively cheaper and
suitable to all types of soil.
• The irrigation water should be of good quality to prevent soil salinity.
38. Pressurized or Modern Irrigation System
• Drip Irrigation system
• Sprinkler Irrigation system
40. Drip irrigation system
• Drip Irrigation system or trickle irrigation is one of the latest and
modern methods of irrigation.
• It is suitable for water scarcity and salt affected soils.
• Water is applied in the root zone of the crop.
• Standard water quality test needed for design and operation of drip
irrigation system.
• Drip irrigation is the best means of water conservation.
• In general, the application efficiency is 90 to 95%, compared with
sprinkler at 70% and furrow irrigation at 60 to 80%, depending on
soil type, level of field and how water is applied to the furrows.
41. Drip components
• A drip irrigation system consists of a pump or overhead tank,
main line, sub-mains, laterals and emitters.
• The mainline delivers water to the sub-mains and the sub-mains
into the laterals.
• The emitters which are attached to the laterals distribute water for
irrigation.
• The mains, sub-mains are usually made of PVC (poly vinyl
chloride) pipes and laterals of LLDPE tubes. The emitters are also
made of PVC material.
• The other components include pressure regulator, filters, valves,
water meter, fertilizer application devices etc.
42. Advantages of drip irrigation
• 1. Water saving - losses due to deep percolation, surface runoff and
transmission are avoided. Evaporation losses occurring in sprinkler
irrigation do not occur in drip irrigation.
• 2. Uniform water distribution
• 3. Application rates can be adjusted by using different size of drippers
• 4. Suitable for wide spaced row crops, particularly coconut and other
horticultural tree crops.
• 5. Soil erosion is reduced
• 6. Better weed control
• 7. Land saving
• 8. Less labour cost
43. Limitation of drip Irrigation
• 1.High initial cost
• 2. Drippers are susceptible to blockage
• 3. Interferes with farm operations and movement of
implements and machineries
• 4. Frequent maintenance
• 5. Trees grown may develop shallow confined root zones
resulting in poor anchorage
45. Sprinkler irrigation system
• Sprinkler irrigation is application simulating rainfall
overhead so overhead sprinklers.
• The sprinkler (overhead or pressure) irrigation system
conveys water to the field through pipes (aluminum or
PVC) under pressure with a system of nozzles.
• This system is designed to distribute the required depth of
water uniformly, which is not possible in surface irrigation.
• Water is applied at a rate less than the infiltration rate of the
soil hence the runoff from irrigation is avoided.
46. Types of sprinkler system
❑Based on arrangement for spraying irrigation water:
• a) Rotating head (or) revolving sprinkler system
• b) Perforated pipe system
❑Based on the portability
• a) Portable system
• b) Semi permanent system
• c) Solid set system
• d) Permanent system.
47. Advantages of sprinkler
• Suitable for undulating topography (sloppy lands)
• Water saving (35-40%) compared to surface irrigation methods.
• Fertilizers and other chemicals can be applied through irrigation
water
• Saving in fertilizers, even distribution and avoids wastage.
• Reduces erosion
• Suitable for coarse textured soils (sandy soils)
• Frost control - protect crops against frost and high temperature
• Drainage problems eliminated
• Saving in land
48. Limitations
• High initial cost
• Efficiency is affected by wind
• Higher evaporation losses in spraying water
• Not suitable for tall crops like sugarcane
• Not suitable for heavy clay soils
• Poor quality water can not be used (Sensitivity of crop to
saline water and clogging of nozzles)
