Seminar Report
Seminar Report
Seminar Report
ON
DRIP IRIGATION
Submitted by
PATNA
CERTIFICATE
This is to certify that the technical seminar presentation entitled “DRIP
IRRIGATION” is submitted by Amit kumar singh (1603081) in practical
fulfillment of the requirement for the award of degree of bachelor of
technology in CIVIL ENGINEERING IN NATIONAL INSTITUTE OF
TECHNOLOGY PATNA.
Introduction
1.1 General
1.2 Methods of irrigation
1.3 Drip or trickle irrigation method
1.4 Need of drip irrigation
2.5 Injectors
System controls
System maintenance
5.5 Chemigation
5.6 Fertilization
6.1 Advantages
6.2 Disadvantages
Conclusion
References
ABSTRACT
Drip irrigation is the slow, even application of low-pressure water to soil and
plants using plastic tubing placed near the plants' root zone. It is an alternative to sprinkler or
furrow methods of irrigating crops. Drip irrigation can be used for crops with high or low water
demands. Why consider drip irrigation? Drip irrigation can help you use water efficiently. A well-
designed drip irrigation system loses practically no water to runoff, deep percolation, or
evaporation. Drip irrigation reduces water contact with crop leaves, stems, and fruit. Thus,
conditions may be less favorable for disease development. Irrigation scheduling can be managed
precisely to meet crop demands, holding the promise of increased yield and quality. Growers and
irrigation professionals often refer to "subsurface drip irrigation," or SDI. When a drip tape or
tube is buried below the soil surface, it is less vulnerable to damage during cultivation or
weeding. With SDI, water use efficiency is maximized because there is even less evaporation or
runoff. Agricultural chemicals can be applied more efficiently with drip irrigation. Since only the
crop root zone is irrigated, nitrogen already in the soil is less subject to leaching losses, and
applied fertilizer can be used more efficiently. In the case of insecticides, less product might be
needed. Make sure the insecticide is labeled for application through drip irrigation. Additional
advantages of drip irrigation include the following.
◆ Drip systems are adaptable to oddly shaped fields or those with uneven topography or soil
texture; these specific factors must be considered when designing the drip system. Drip systems
also can work well where other irrigation systems are inefficient because parts of the field have
excessive infiltration, water puddling, or runoff. Sustainable agriculture techniques Drip irrigation
tubing used to irrigate wine grapes.
◆ Drip irrigation can be helpful if water is scarce or expensive. Because evaporation, runoff,
and deep percolation are reduced, and irrigation uniformity is improved, it is not necessary to
"overwater" parts of a field to adequately irrigate the more difficult parts.
◆ Precise application of nutrients is possible using drip irrigation. Fertilizer costs and nitrate
losses can be reduced. Nutrient applications can be better timed to meet plants' needs.
◆ Drip irrigation systems can be designed and managed so that the wheel traffic rows are dry
enough to allow tractor operations at any time. Timely application of herbicides, insecticides, and
fungicides is possible.
◆ Proven yield and quality responses to drip irrigation have been observed in onion, broccoli,
cauliflower, lettuce, melon, tomato, and cotton.
◆ A drip irrigation system can be automated. For an example of automated drip irrigation, see
the Malheur Experiment Station's 1998 onion drip irrigation trial results. (See "Additional
resources," page 6.) There are some disadvantages to drip irrigation. For example:
◆ Drip irrigation systems typically cost $500 to $1,200 or more per acre. Part of the cost is a
capital investment useful for several years, and part is annual. Systems can be more elaborate and
costly than necessary. Growers new to drip irrigation might want to start with a simple system on
a small acreage.
◆ Drip tape or tubing must be managed to avoid leaking or plugging. Drip emitters are easily
plugged by silt or other particles not filtered out of the irrigation water. Emitter plugging also
can be caused by algae growing in the tape or by chemical deposits at the emitter.
CHAPTER 1
INTRODUCTION
1.1 GENERAL
Irrigation may be defined as the process of supplying water to land by artificial means for the
purpose of cultivation.Ordinarily water is supplied to land by nature through rain but generally it
is not enough for the proper growth of plants.As such as the basic objective of irrigation is to
supplement the natural supply of water to land so as to obtain the an optimum yield from the crop
grown on the land.
In order to achieve this objective of irrigation, an irrigation system is required to developed,
which involves planning, designing, construction, operation and maintenance of various
irrigation works viz, a source of water supply, a distribution system for carrying water from the
source to the agricultural land and its application on the land, and various other associated
works.The factors which necessitate irrigation are:
Ø Inadequate rainfall
Ø Uneven distribution of rainfall
Ø Growing a number of crops during a year
Ø Growing superior crops
1.2 METHODS OF IRRIGATION
Irrigation methods are commonly designated according to the manner in which water is
applied to the land to be irrigated.
1.2.1 Surface Irrigation Methods
The water is applied by spreading in it sheets or small streams on the land to be irrigated.
These methods are adopted for perennial irrigation system.
1.2.2 Sprinkler Irrigation Methods
The irrigation water is applied to the land in the form of spray, somewhat as in ordinary rain. It
can be used for all the crops except rice and jute and for almost all soils except very heavy
soils with very low filtration rates.
1.2.3 Sub-Surface Irrigation Methods
The water is applied below the ground surface so that it is supplied directly to the root zone of
the plants. The main advantages of these methods are that the evaporation losses are
considerably reduced and the hindrance caused to cultivation by the presence of borders,
pipes and field channels in the other methods of irrigation is elimina ted.
1.3 DRIP OR TRICKLE IRRIGATION METHOD
Drip irrigation,also known as trickle irrigation or micro irrigation is one of the sub-surface
irrigation method of applying water or frequent application of water to crops through small
emitters in the vicinity of the root zone, wetting a limited amount of surface area and depth of
soil. The theory behind drip irrigation is to apply sufficient moisture to the root of the crops to
prevent water stress. A major difference between drip system and most other systems is that the
balance between crop evapotranspiration and applied water is maintained over limited periods of
24 to 72 hours. The conversion from sprinkler to drip irrigation can result in water use reduction
of 50% and double yield. This is a result of improved water use and fertility and reduced disease
and weed pressure.
1.4 NEED OF DRIP IRRIGATION
Drip irrigation can help you use water efficiently. A well-designed drip irrigation system loses
practically no water to runoff, deep percolation, or evaporation. Drip irrigation reduces water
contact with crop leaves, stems, and fruit. Thus conditions may be less favorable for the onset of
diseases. Irrigation scheduling can be managed precisely to meet crop demands, holding the
promise of increased yield and quality. Growers and irrigation professionals often refer to
"subsurface drip irrigation,"or SDI. When a drip tape or tube is buried below the soil surface, it is
less vulnerable to damage during cultivation or weeding. With SDI, water use efficiency is
maximized because there is even less evaporation or runoff.Agricultural chemicals can be
applied more efficiently with drip irrigation. Since only the crop root zone is irrigated, nitrogen
already in the soil is less subject to leaching losses, and applied fertilizer N can be used more
efficiently. In the case of insecticides, less product might be needed.
CHAPTER 2
COMPONENTS AND WORKING
In drip irrigation, also known as trickle irrigation, water is applied in the form of drops directly
near the base of the plant. Water is conveyed through a system of flexible pipelines, operating at
low pressure, and is applied to the plants through drip nozzles. This technique is also known as
‘feeding bottle’ technique where by the soil is maintained in the most congenital form by keeping
the soil-water-air proportions in the optimum range. Drip irrigation limits the water supplied for
consumptive use of the plant by maintaining minimum soil moisture, equal to the field capacity,
thereby maximizing the saving. The system permits the fine control on the application of
moisture and nutrients at stated frequencies.
Fig 2.1 Drip Irrigation System Layout and its parts (Credits:Eric Simonne)
2.5 INJECTORS
Injectors allow the introduction of fertilizer, chemicals and maintenance products into the
irrigation system. Florida law requires the use of an anti-siphoning device (also called backflow-
prevention device) when fertilizer, chemicals or any other products are injected into a drip-
irrigation system. Backflow-prevention devices ensure the water always moves from the water
source to the field. The devices prevent chemicals in the water from polluting the water source.
The most common injectors used with small drip-irrigation systems are the Venturi (or Mazzei)
injector and the Dosatron.Because Venturi injectors involve no moving parts and are less
expensive, they are commonly used on small farms. The injector is typically located as close as
possible to the irrigation zone, but before the filter.
The whole field is divided into suitable plots. A secondary line is provided for each such plot,
and a number of trickle lines are connected to each secondary line. A discharge regulator is
provided at the beginning of each secondary line, and its capacity is fixed in accordance with the
size and the number of nozzles used. The automatic valve at the head is so adjusted to deliver the
desired quantity of water and the irrigation terminates automatically after this amount is
discharged.
CHAPTER 3
DESIGN AND LAYOUT
3.1 HOLTICULTURAL CONSIDERATIONS
The goal of drip irrigation is to bring water to the crop. The main parameters that determine crop
water use are the type of crop planted and row spacing. A drip irrigation system should be able to
supply 110% - 120% of crop water needs. In other words, the system should be slightly
oversized. In designing a drip-irrigation system, it is common to consider that vegetable crops
ordinarily need approximately 1.5 acre-inches of water for each week of growth or
approximately 20 acre-inches of water per crop. Actual crop water use will be more or less than
this amount, depending on weather and irrigation efficiency.
Start with what is already available, the water source or the field. If a water source is already
available (pond or well), the amount of water available may be used to calculate the maximum
size of each irrigation zone.
If no water source is available, the amount of water needed by the crop, based on the size of the
planted area, may be used to calculate the type of well or pond size needed.
Because differences in altitudes affect water pressure, it is preferable to lay out beds
perpendicular to the slope. This arrangement of rows is called "contour farming”.
Excessive water velocities (>5 feet/second) in the lines, the result of a too-small diameter are
likely to create a water hammer (pressure wave), which can damage the delivery lines. Growers
should be aware of the maximum acreage that can be
irrigated with different pipe sizes at a water velocity of 5 feet/second.
The maximum length of drip tape should be based on the manufacturer's recommendation and
the actual terrain slope. Typically 400 - 600 feet are
maximum values for drip-tape length. Excessive length of laterals will result in poor uniformity
and uneven water application. When the field is longer than 400 - 600 feet, consider placing the
secondary (sub main) line in the middle of the field rather than at the end and connect drip tape
on both sides.
Table 3.1 Maximum length of drip tape (feet) and maximum irritable field size (acre) with
low-and medium-flow drip tape at a water velocity of 5-feet-per-second for selected diameters
of Class 160 PVC pipes
CHAPTER 4
SYSTEM CONTROLS
System controls are devices that allow the user to monitor how the drip-irrigation system
performs. These controls help ensure the desired amount of water is applied to the crop
throughout the growing season. The different devices used for the control are:
Ø Pressure Regulators
Ø Water Meters
Ø Pressure Gauges
Ø Soil moisture Measuring Devices
Ø Electrical Timers
4.1 PRESSURE REGULATORS
Pressure regulators, installed in-line with the system, regulate water pressure at a given water
flow there by helping to protect system components against damaging surges in water pressure.
Pressure surges may occur when the water in the pipe has a velocity >5 feet /second ("water
hammer") or when water flowing in the pipe has no avenue for release due to a closed valve or a
clog in the pipe.
The goal of drip-irrigation maintenance is to preserve the high uniformity of water application
allowed by drip irrigation. A successful program of maintenance for a drip-irrigation system is
based on the prevention-is-the-best-medicine approach. It is
easier to prevent a drip tape from clogging than to"unclog" it or replace it.
Table 5.1 Water quality parameter levels for emitter plugging potential
of Drip irrigation systems
5.6 FERTILIZATION
Soil microorganisms convert nitrogen (N) fertilizers to nitrate. Nitrate is water soluble, available
to plants, and subject to leaching loss.Fertilizer can be injected through the drip system. Fertilizer
usually is introduced into the irrigation system in front of the filter station so the filters can
remove any precipitates that occur in the solution Fertilizers containing sulfate, phosphate,
calcium, or anhydrous or aqua ammonium can lead to solid chemical precipitation inside the drip
lines, which can block emitters.
5.7 PLACEMENT OF TAPE
The drip tape must be close enough to the surface to germinate the seed if necessary, or a
portable sprinkler system should be available. For example, a tape tube 4 to 5 inches deep has
successfully germinated onion seeds in silt loam soil. Tape at 12 inches failed to uniformly
germinate onions.
6.1.4 Simplicity
Polyvinyl chloride (pvc) and polyethylene parts are widely available in several diameters and are
easy to assemble. Many customized, easy-to-install connectors, end caps, and couplers are
available in different diameters. Cutting and gluing allows for timely repairs.
6.1.6 Automation
Drip-irrigation application may be simply managed and programmed with an AC - or battery-
powered controller, thereby reducing labor cost.
6.1.7 Adaptation
Drip systems are adaptable to oddly shaped fields or those with uneven topography
or soil texture, thereby eliminating the underutilized or non-cropped corners and maximizing the
use of available land.
6.2 DISADVANTAGES
6.2.4 Safety
Drip tubing may be lifted by wind or may be displaced by animals unless the drip tape is
covered with mulch, fastened with wire anchor pins,or lightly covered with soil.