3. Introduction
Irrigation is an artificial application of water to the
soil through various systems of tubes, pumps, and
sprays.
Irrigation is normally used in areas where rainfall is
inconsistent or dry conditions or drought is expected.
4. Drip Irrigation
Drip irrigation is a micro irrigation method in which
the rate of water application is very low and without
any pressure. i.e., drop by drop
Drip irrigation is based on the basic concept of
irrigation only the roots zone of crop , rather than the
entire land surface on which the crop is grow.
5. Water flows from the emission
points through the soil by
capillarity and gravity.
The soil moisture content of
the
crop root zone is maintain at near
optimum level to facilate optimum
crop growth and production.
8. Advantages of Drip
Irrigation
Less requirement of irrigation water
Water supply at optimum level.
Water logging is avoided
High yield
Over irrigation is avoided
Variation in application rate
Reduced labour cost
Weed control
9. Increase in net irrigable area
Highly uniform distribution of water i.e., Controlled
by output of each nozzle No soil erosion
Suitable for any topography
Maintenance of high surface temperature
Improved disease and pest control
Tolerance to windy atmospheric condition
10. Disadvantages of drip
irrigation
High cost :
drip irrigation systems are expensive because of there requirements of
large quantity of piping & filtration equipment to clean the water.
Expense:
Initial cost can be more than overhead systems.
Waste:
The sun can affect the tubes used for drip irrigation, shortening their
usable life. Longevity is variable.
Clogging:
If the water is not properly filtered and the equipment not properly
maintained, it can result in clogging.
Drip tape causes extra cleanup costs after harvest. You'll need to plan for drip
tape winding, disposal, recycling or reuse.
This method is not suitable for closely planted crops such as wheat
11. COMPARISON
Drip method
Flood method
Water saving
High,
between 40 and 100 %
Less. High rates of
evaporation, surface run off
and percolation
Irrigation efficiency
80 – 90 %
30 - 50 %
Weed problem
Diseases and pests
Efficiency of fertilizer use
High
Even saline water can be
Only normal water can be
used
Suitable water
Almost nil
used
Relatively less
High
Very high since supply is
regulated
Heavy losses due to leaching
12. Drip method
Water logging
Water control
Flood method
Nil
High
Can be regulated easily
Cost benefit ratio (additional
Excluding water savings: 1.3 -
amount in rupees for every
13.3, Including water savings:
rupee invested)
Not much control
2.8 - 30.0
Capital cost/ha
Yield increase
Rs 15,000 to 40, 000
20 - 100 % higher than flood
method
Between 1.8 and 3.9
depending ––
on crop spacing
Less compared to drip
15. Pumping set:
To create a pressure about 2.5
Kg/sq cm to regulate the
amount of water to be
supplied.
• Filter :
To filter the water in
Order to remove the
suspended
impurities
from water.
16. Main lines:
It is a Distribution system in drip
irrigation. Rigid PVC and high density
polyethylene pipes are used as main
pipes to minimized corrosion and
clogging.
Pipes of 65 mm diameter and with
pressure rating of 4 to 10 kg/sq. cm
Sub Main:
It is usually connected to the main lines
through a control valve assembly.
The function of its to distributes water
uniformly to a number laterals.
17. Drippers/emitters:
It is fitted to a drip irrigation
lateral and intended to emit water
in the form of drops or continuous
flow at emitter rates not exceeding
15 liters/hr.
Drippers
function as energy
dissipated, reducing the inlet
pressure head in the lateral, which
generally range from 0.3 to 1.5
atmosphere .
18. Design of Drip irrigation
system
Data collection
Types of soil
Infiltration characteristics of soil
Types of crop
Consumptive use of water by crops
Water quality
Climate condition
Availability of funds
Contour map
19. Design procedures
Prepare on inventory of available resources & operating
conditions
Determine the water requirement to be met by the drip system
Determine the appropriate type of system
Determine the type and design of emitters
Determine the capacity of pumping system
Decide on the economic sizes of the pumping system
Determine the maximum and minimum operating pressure and
the minimum efficiency required
Determine the appropriate filtering system
Determine the requirement of the fertilization system
Plan field evaluation
Prepare drawings, specification, cost ,schedules, installation,
operations ,maintenance.
20. Emitter Selection
The efficiency Of Drip irrigation system depends
mainly on the selection of the type of emitter and its
design.
Characteristic of emitter that influence the efficiency
of irrigation system is Discharge rate
Critical items in emitter selection are the % area
wetted(Pw) and the emitter reliability.
The density of emission points required to obtain Pw ≥
33% .
21. Manufacturing Variation in Emitter:
Cv = S/Q
= (q₁²+q₂²….+ qn ²-n(q) ²)⅟2
/ q(n-1) ⅟
2
In Which,
Cv = emitter coefficient of manufacturing variation,
q₁, q₂… qn = individual emitter discharge rate values,
N = Number of emitter in sample,
Q = Average discharge rate of the emitters sampled,
S = Standard deviation of the discharge rates of the
sample.
22. Recommended rangers of Cv
(emitter coefficient of manufacturing variation)
<0.05
Excellent
0.05 to 0.07
Average
0.07 to 0.11
Marginal
0.11 to 0.15
Poor
> 0.15
unacceptable
23. Discharge of Drippers
q= khx
In which,
q = Discharge of the dripper, volume/time
P= operating pressure, force/area
X= constants for specified emitters
24. Irrigation water requirement
Vm = Kc x Kp x Cc x Ep x A
In which
Vm = Monthly Irrigation water requirement,
Kc = Crop co efficient
Cc = Canopy factor
Kp= Pan evaporation factor (0.8)
Ep = Normal monthly evaporation
A = Area to be irrigated, m2
25. Capacity of drip irrigation system
Q = Vd x T (na x t)
In which
Q = Capacity of drip system,
Vd = Daily water requirement,
T = Irrigation interval days
na = Water application efficiency
t = Duration
Qp = Q/n
Qp = Discharge per plant
n = Number of plant
26. Numbers of Laterals required:
For vegetable crops – 1 lateral for each slop.
For orchards – 1 to 2 /each row
Number of drippers per plant:
(% total area shaded by the tree x area per tree) / (effective
area wetted by a single emitter).
27. Area irrigated by a dripper :
Ai = (L x S x P) / (100 x Ne )
Ai = Area irrigated, m2
L = Spacing between adjacent plant rows, m
S = Spacing between emission points, m
P = % of cropped area to be irrigated
Ne = Numbers of drippers at each emission point
28. Benefits to Farmers :
More than 70% of Indian farmers
are
small
scale
operators
cultivating plots less than one
hectare. Irratic rainfall pattern
play havoc into the livelihoods of
the small farmers who do not have
any alternate supply of water.
29. CONCLUSION
• Drip irrigation system is an economical and very
efficient system of irrigating for vegetables, row
crops etc.
• Drip irrigated crops use less water compared to
overhead irrigated crops.
• Drip irrigation increase yields
