Drip irrigation

Drip irrigation

Overview
Drip irrigation, also known as trickle irrigation or microirrigation or localized irrigation , is an irrigation
Irrigation
Irrigation may be defined as the science of artificial application of water to the land or soil. It is used to assist in the growing of agricultural crops, maintenance of landscapes, and revegetation of disturbed soils in dry areas and during periods of inadequate rainfall...

 method which saves water and fertilizer by allowing water
Water
Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...

 to drip slowly to the root
Root
In vascular plants, the root is the organ of a plant that typically lies below the surface of the soil. This is not always the case, however, since a root can also be aerial or aerating . Furthermore, a stem normally occurring below ground is not exceptional either...

s of plants, either onto the soil
Soil
Soil is a natural body consisting of layers of mineral constituents of variable thicknesses, which differ from the parent materials in their morphological, physical, chemical, and mineralogical characteristics...

 surface or directly onto the root zone
Rhizosphere
The rhizosphere is the narrow region of soil that is directly influenced by root secretions and associated soil microorganisms. Soil which is not part of the rhizosphere is known as bulk soil. The rhizosphere contains many bacteria that feed on sloughed-off plant cells, termed rhizodeposition, and...

, through a network of valve
Valve
A valve is a device that regulates, directs or controls the flow of a fluid by opening, closing, or partially obstructing various passageways. Valves are technically pipe fittings, but are usually discussed as a separate category...

s, pipes
Pipe (material)
A pipe is a tubular section or hollow cylinder, usually but not necessarily of circular cross-section, used mainly to convey substances which can flow — liquids and gases , slurries, powders, masses of small solids...

, tubing
Tubing
Tubing may refer to:* Tubing , flexible hose or pipe * Tubing , the act of riding an inner tube* Structural tubing* Plumbing tube used in domestic water systems* Inserting a tube* Brass instrument tubing...

, and emitter
Emitter
-In general:*A device used to exude any signal, beacon, light, odor, liquid, fragrance, ionizing particles or any other type of signal.-In horticulture:*A device used in drip irrigation.-In electronics and instrument physics:...

s.It is done with the help of narrow tubes which delivers water directly to the base of the plant.

Drip irrigation has been used since ancient times when buried clay pots were filled with water, which would gradually seep into the grass.
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Encyclopedia
Drip irrigation, also known as trickle irrigation or microirrigation or localized irrigation , is an irrigation
Irrigation
Irrigation may be defined as the science of artificial application of water to the land or soil. It is used to assist in the growing of agricultural crops, maintenance of landscapes, and revegetation of disturbed soils in dry areas and during periods of inadequate rainfall...

 method which saves water and fertilizer by allowing water
Water
Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...

 to drip slowly to the root
Root
In vascular plants, the root is the organ of a plant that typically lies below the surface of the soil. This is not always the case, however, since a root can also be aerial or aerating . Furthermore, a stem normally occurring below ground is not exceptional either...

s of plants, either onto the soil
Soil
Soil is a natural body consisting of layers of mineral constituents of variable thicknesses, which differ from the parent materials in their morphological, physical, chemical, and mineralogical characteristics...

 surface or directly onto the root zone
Rhizosphere
The rhizosphere is the narrow region of soil that is directly influenced by root secretions and associated soil microorganisms. Soil which is not part of the rhizosphere is known as bulk soil. The rhizosphere contains many bacteria that feed on sloughed-off plant cells, termed rhizodeposition, and...

, through a network of valve
Valve
A valve is a device that regulates, directs or controls the flow of a fluid by opening, closing, or partially obstructing various passageways. Valves are technically pipe fittings, but are usually discussed as a separate category...

s, pipes
Pipe (material)
A pipe is a tubular section or hollow cylinder, usually but not necessarily of circular cross-section, used mainly to convey substances which can flow — liquids and gases , slurries, powders, masses of small solids...

, tubing
Tubing
Tubing may refer to:* Tubing , flexible hose or pipe * Tubing , the act of riding an inner tube* Structural tubing* Plumbing tube used in domestic water systems* Inserting a tube* Brass instrument tubing...

, and emitter
Emitter
-In general:*A device used to exude any signal, beacon, light, odor, liquid, fragrance, ionizing particles or any other type of signal.-In horticulture:*A device used in drip irrigation.-In electronics and instrument physics:...

s.It is done with the help of narrow tubes which delivers water directly to the base of the plant.

History


Drip irrigation has been used since ancient times when buried clay pots were filled with water, which would gradually seep into the grass. Modern drip irrigation began its development in Afghanistan
Afghanistan
Afghanistan , officially the Islamic Republic of Afghanistan, is a landlocked country located in the centre of Asia, forming South Asia, Central Asia and the Middle East. With a population of about 29 million, it has an area of , making it the 42nd most populous and 41st largest nation in the world...

 in 1866 when researchers began experimenting with irrigation
Irrigation
Irrigation may be defined as the science of artificial application of water to the land or soil. It is used to assist in the growing of agricultural crops, maintenance of landscapes, and revegetation of disturbed soils in dry areas and during periods of inadequate rainfall...

 using clay pipe to create combination irrigation and drainage
Drainage
Drainage is the natural or artificial removal of surface and sub-surface water from an area. Many agricultural soils need drainage to improve production or to manage water supplies.-Early history:...

 systems. In 1913, E.B. House at Colorado State University
Colorado State University
Colorado State University is a public research university located in Fort Collins, Colorado. The university is the state's land grant university, and the flagship university of the Colorado State University System.The enrollment is approximately 29,932 students, including resident and...

 succeeded in applying water to the root zone of plants without raising the water table
Water table
The water table is the level at which the submarine pressure is far from atmospheric pressure. It may be conveniently visualized as the 'surface' of the subsurface materials that are saturated with groundwater in a given vicinity. However, saturated conditions may extend above the water table as...

. Perforated pipe was introduced in Germany in the 1920s .
Usage of plastic to hold and distribute water in drip irrigation was developed in Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...

 by Hannis Thill. Refinement of this idea (involving a plastic emitter) was furthered in Israel
Israel
The State of Israel is a parliamentary republic located in the Middle East, along the eastern shore of the Mediterranean Sea...

 by Simcha Blass
Simcha Blass
Simcha Blass was an Israeli water engineer, a main figure of water development in Israel, initiator, introducer and developer of new drip irrigation systems, inventor of new dripper .-Early life:Simcha Blass was born in Warsaw, Poland, which was then part of the Russian Empire, to a Jewish orthodox...

 and his son Yeshayahu. Instead of releasing water through tiny holes, blocked easily by tiny particles, water was released through larger and longer passageways by using velocity to slow water.

In the United States, in the early 1960s, the first drip tape, called Dew Hose, was developed by Richard Chapin of Chapin Watermatics (first system established during 1964). Beginning in 1989, Jain irrigation helped pioneer effective water-management through drip irrigation in India. Jain irrigation also introduced the `Integrated System Approach’, One-Stop-Shop for Farmers, `Infrastructure Status to Drip Irrigation & Farm as Industry.’ The latest developments in the field involve even further reduction in drip rates being delivered and less tendency to clog.

Modern drip irrigation has arguably become the world's most valued innovation in agriculture
Agriculture
Agriculture is the cultivation of animals, plants, fungi and other life forms for food, fiber, and other products used to sustain life. Agriculture was the key implement in the rise of sedentary human civilization, whereby farming of domesticated species created food surpluses that nurtured the...

 since the invention of the impact sprinkler
Impact sprinkler
An Impact sprinkler is a type of Irrigation sprinkler.-Development:The original horizontal action impact drive sprinkler was invented by Los Angeles citrus farmer Orton Englehardt in 1933 and patented in 1935...

 in the 1930s, which offered the first practical alternative to surface irrigation
Surface irrigation
Surface irrigation is defined as the group of application techniques where water is applied and distributed over the soil surface by gravity. It is by far the most common form of irrigation throughout the world and has been practiced in many areas virtually unchanged for thousands of years.Surface...

. Drip irrigation may also use devices called micro-spray heads, which spray water in a small area, instead of dripping emitters. These are generally used on tree and vine crops with wider root zones. Subsurface drip irrigation (SDI) uses permanently or temporarily buried dripperline or drip tape
Drip tape
Drip tape is a type of thin walled dripperline used in drip irrigation. The first drip tape, a product known as "Dew Hose", was developed in Watertown, New York, in the 1960s by Richard D. Chapin of Chapin Watermatics, USA....

 located at or below the plant roots. It is becoming popular for row crop irrigation, especially in areas where water
Water
Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...

 supplies are limited or recycled water is used for irrigation. Careful study of all the relevant factors like land topography, soil, water, crop and agro-climatic conditions are needed to determine the most suitable drip irrigation system and components to be used in a specific installation.

Components and operation


Componen(listed in order from water source):
  • Pump
    Pump
    A pump is a device used to move fluids, such as liquids, gases or slurries.A pump displaces a volume by physical or mechanical action. Pumps fall into three major groups: direct lift, displacement, and gravity pumps...

     or pressurized water source
  • Water Filter(s) - Filtration Systems: Sand Separator like Hydro-Cyclone, Screen filter
    Screen filter
    A screen filter is a type of filter using a rigid or flexible screen to separate sand and other fine particles out of water for irrigation or industrial applications...

    s, Media Filters, Disc Filters.
  • Fertigation Systems (Venturi injector) and Chemigation Equipment (optional)
  • Backwash Controller (Backflow Preventer)
  • Pressure Control Valve (Pressure Regulator)
  • Main Line (larger diameter Pipe and Pipe Fittings)
  • Hand-operated, electronic, or hydraulic Control Valves and Safety Valves
  • Smaller diameter polytube (often referred to as "laterals")
  • Poly fittings and Accessories (to make connections)
  • Emitting Devices at plants (ex. Emitter
    Emitter
    -In general:*A device used to exude any signal, beacon, light, odor, liquid, fragrance, ionizing particles or any other type of signal.-In horticulture:*A device used in drip irrigation.-In electronics and instrument physics:...

     or Drippers, micro spray heads, inline drippers or inline driptube
  • Note that in Drip irrigation systems Pump and valve
    Valve
    A valve is a device that regulates, directs or controls the flow of a fluid by opening, closing, or partially obstructing various passageways. Valves are technically pipe fittings, but are usually discussed as a separate category...

    s may be manually or automatically operated by a controller
    Controller (irrigation)
    An irrigation controller is a device to operate automatic irrigation systems such as lawn sprinklers and drip irrigation systems. Most controllers have a means of setting the frequency of irrigation, the start time, and the duration of watering...

    .


Most large drip irrigation systems employ some type of filter to prevent clogging of the small emitter flow path by small waterborne particles. New technologies are now being offered that minimize clogging. Some residential systems are installed without additional filters since potable water is already filtered at the water treatment plant. Virtually all drip irrigation equipment manufacturers recommend that filters be employed and generally will not honor warranties unless this is done. Last line filters just before the final delivery pipe are strongly recommended in addition to any other filtration system due to fine particle settlement and accidental insertion of particles in the intermediate lines.

Drip and subsurface drip irrigation is used almost exclusively when using recycled municipal waste water. Regulations typically do not permit spraying water through the air that has not been fully treated to potable water standards.

Because of the way the water is applied in a drip system, traditional surface applications of timed-release fertilizer
Fertilizer
Fertilizer is any organic or inorganic material of natural or synthetic origin that is added to a soil to supply one or more plant nutrients essential to the growth of plants. A recent assessment found that about 40 to 60% of crop yields are attributable to commercial fertilizer use...

 are sometimes ineffective, so drip systems often mix liquid fertilizer with the irrigation water. This is called fertigation
Fertigation
Fertigation is the application of fertilizers, soil amendments, or other water-soluble products through an irrigation system.Chemigation, a related and sometimes interchangeable term, is the application of chemicals through an irrigation system...

; fertigation and chemigation (application of pesticide
Pesticide
Pesticides are substances or mixture of substances intended for preventing, destroying, repelling or mitigating any pest.A pesticide may be a chemical unicycle, biological agent , antimicrobial, disinfectant or device used against any pest...

s and other chemicals to periodically clean out the system, such as chlorine
Chlorine
Chlorine is the chemical element with atomic number 17 and symbol Cl. It is the second lightest halogen, found in the periodic table in group 17. The element forms diatomic molecules under standard conditions, called dichlorine...

 or sulfuric acid
Sulfuric acid
Sulfuric acid is a strong mineral acid with the molecular formula . Its historical name is oil of vitriol. Pure sulfuric acid is a highly corrosive, colorless, viscous liquid. The salts of sulfuric acid are called sulfates...

) use chemical injectors such as diaphragm pump
Diaphragm pump
A diaphragm pump is a positive displacement pump that uses a combination of the reciprocating action of a rubber, thermoplastic or teflon diaphragm and suitable non-return check valves to pump a fluid...

s, piston pump
Piston pump
A piston pump is a type of positive displacement pump where the high-pressure seal reciprocates with the piston. Piston pumps can be used to move liquids or compress gases.-Types:* Axial piston pump* Radial piston pump...

s, or venturi pumps. The chemicals may be added constantly whenever the system is irrigating or at intervals. Fertilizer savings of up to 95% are being reported from recent university field tests using drip fertigation and slow water delivery as compared to timed-release and irrigation by micro spray heads.

Properly designed, installed, and managed, drip irrigation may help achieve water conservation
Water conservation
Water conservation refers to reducing the usage of water and recycling of waste water for different purposes such as cleaning, manufacturing, and agricultural irrigation.- Water conservation :Water conservation can be defined as:...

 by reducing evaporation
Evaporation
Evaporation is a type of vaporization of a liquid that occurs only on the surface of a liquid. The other type of vaporization is boiling, which, instead, occurs on the entire mass of the liquid....

 and deep drainage when compared to other types of irrigation such as flood or overhead sprinklers since water can be more precisely applied to the plant roots. In addition, drip can eliminate many diseases that are spread through water contact with the foliage. Finally, in regions where water supplies are severely limited, there may be no actual water savings, but rather simply an increase in production while using the same amount of water as before. In very arid regions
Déserts
Déserts is a piece by Edgard Varèse for brass , percussion , piano, and tape. Percussion instruments are exploited for their resonant potential, rather than used solely as accompaniment...

 or on sandy soils
Psamment
In USDA soil taxonomy, a Psamment is defined as an Entisol which consists basically of unconsolidated sand deposits, often found in shifting sand dunes but also in areas of very coarse-textured parent material subject to millions of years of weathering. This latter case is characteristic of the...

, the preferred method is to apply the irrigation water as slowly as possible.

Pulsed irrigation is sometimes used to decrease the amount of water delivered to the plant at any one time, thus reducing runoff or deep percolation. Pulsed systems are typically expensive and require extensive maintenance. Therefore, the latest efforts by emitter manufacturers are focused toward developing new technologies that deliver irrigation water at ultra-low flow rates, i.e. less than 1.0 liter per hour. Slow and even delivery further improves water use efficiency without incurring the expense and complexity of pulsed delivery equipment.

Drip irrigation is used by farm
Farm
A farm is an area of land, or, for aquaculture, lake, river or sea, including various structures, devoted primarily to the practice of producing and managing food , fibres and, increasingly, fuel. It is the basic production facility in food production. Farms may be owned and operated by a single...

s, commercial greenhouse
Greenhouse
A greenhouse is a building in which plants are grown. These structures range in size from small sheds to very large buildings...

s, and residential gardeners.

Drip irrigation is adopted extensively in areas of acute water scarcity and especially for crops such as coconut
Coconut
The coconut palm, Cocos nucifera, is a member of the family Arecaceae . It is the only accepted species in the genus Cocos. The term coconut can refer to the entire coconut palm, the seed, or the fruit, which is not a botanical nut. The spelling cocoanut is an old-fashioned form of the word...

s, containerized landscape trees, grapes, banana
Banana
Banana is the common name for herbaceous plants of the genus Musa and for the fruit they produce. Bananas come in a variety of sizes and colors when ripe, including yellow, purple, and red....

s, ber
BER
See here for Ber Ber is a tropical fruit growing on the tree Ziziphus mauritiana.BER is the IATA area code for airports in the Berlin region, Germany:* Berlin-Tegel Airport...

, brinjal, citrus
Citrus
Citrus is a common term and genus of flowering plants in the rue family, Rutaceae. Citrus is believed to have originated in the part of Southeast Asia bordered by Northeastern India, Myanmar and the Yunnan province of China...

, strawberries, sugarcane
Sugarcane
Sugarcane refers to any of six to 37 species of tall perennial grasses of the genus Saccharum . Native to the warm temperate to tropical regions of South Asia, they have stout, jointed, fibrous stalks that are rich in sugar, and measure two to six metres tall...

, cotton
Cotton
Cotton is a soft, fluffy staple fiber that grows in a boll, or protective capsule, around the seeds of cotton plants of the genus Gossypium. The fiber is almost pure cellulose. The botanical purpose of cotton fiber is to aid in seed dispersal....

, maize
Maize
Maize known in many English-speaking countries as corn or mielie/mealie, is a grain domesticated by indigenous peoples in Mesoamerica in prehistoric times. The leafy stalk produces ears which contain seeds called kernels. Though technically a grain, maize kernels are used in cooking as a vegetable...

, and tomato
Tomato
The word "tomato" may refer to the plant or the edible, typically red, fruit which it bears. Originating in South America, the tomato was spread around the world following the Spanish colonization of the Americas, and its many varieties are now widely grown, often in greenhouses in cooler...

es.

Drip Irrigation for Garden


Drip irrigation for garden available in drip kits are increasingly popular for the homeowner and consist of a timer
Timer
A timer is a specialized type of clock. A timer can be used to control the sequence of an event or process. Whereas a stopwatch counts upwards from zero for measuring elapsed time, a timer counts down from a specified time interval, like an hourglass.Timers can be mechanical, electromechanical,...

, hose
Hose (tubing)
A hose is a hollow tube designed to carry fluids from one location to another. Hoses are also sometimes called pipes , or more generally tubing...

 and emitter
Emitter
-In general:*A device used to exude any signal, beacon, light, odor, liquid, fragrance, ionizing particles or any other type of signal.-In horticulture:*A device used in drip irrigation.-In electronics and instrument physics:...

. Hoses that are 4 mm in diameter are used to irrigate flower pots.

Advantage and disadvantages


The advantages of drip irrigation are:
  • Minimized fertilizer/nutrient loss due to localized application and reduced leaching.
  • High water application efficiency.
  • Levelling of the field not necessary.
  • Ability to irrigate irregular shaped fields.
  • Allows safe use of recycled water.
  • Moisture within the root zone can be maintained at field capacity.
  • Soil type plays less important role in frequency of irrigation.
  • Minimized soil erosion.
  • Minimized weed growth
  • Highly uniform distribution of water i.e., controlled by output of each nozzle.
  • Lower labour cost.
  • Variation in supply can be regulated by regulating the valves and drippers.
  • Fertigation
    Fertigation
    Fertigation is the application of fertilizers, soil amendments, or other water-soluble products through an irrigation system.Chemigation, a related and sometimes interchangeable term, is the application of chemicals through an irrigation system...

     can easily be included with minimal waste of fertilizers.
  • Foliage remains dry thus reducing the risk of disease.
  • Usually operated at lower pressure than other types of pressurised irrigation, reducing energy costs.


The disadvantages of drip irrigation are:
  • 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 irrigation might be unsatisfactory if herbicides or top dressed fertilizers need sprinkler irrigation for activation.
  • Drip tape causes extra cleanup costs after harvest. You'll need to plan for drip tape winding, disposal, recycling or reuse.
  • Waste of water, time & harvest, if not installed properly. These systems require careful study of all the relevant factors like land topography, soil, water, crop and agro-climatic conditions, and suitability of drip irrigation system and its components.
  • Germination Problems. In lighter soils subsurface drip may be unable to wet the soil surface for germination. Requires careful consideration of the installation depth.
  • Salinity. Most drip systems are designed for high efficiency, meaning little or no leaching fraction. Without sufficient leaching, salts applied with the irrigation water may build up in the root zone, usually at the edge of the wetting pattern. On the other hand, drip irrigation avoids the high capillary potential of traditional surface-applied irrigation, which can draw salt deposits up from deposits below.

Emitting Pipe


A Emitting Pipe is a type of drip irrigation tubing with emitters pre-installed at the factory with specific distance & flow per hour as per crop distance.

Emitter



An emitter is also called a dripper and is used to transfer water from a pipe or tube to the area that is to be irrigated. Typical emitter flow rates are from 0.16 to 4.0 US gallons per hour (0.6 to 16 L/h). In many emitters, flow will vary with pressure, while some emitters are pressure compensating.

These emitters employ silicone
Silicone
Silicones are inert, synthetic compounds with a variety of forms and uses. Typically heat-resistant and rubber-like, they are used in sealants, adhesives, lubricants, medical applications , cookware, and insulation....

 diaphragm
Diaphragm (mechanics)
In mechanics, a diaphragm is a sheet of a semi-flexible material anchored at its periphery and most often round in shape. It serves either as a barrier between two chambers, moving slightly up into one chamber or down into the other depending on differences in pressure, or as a device that...

s or other means to allow them to maintain a near-constant flow over a range of pressure
Pressure
Pressure is the force per unit area applied in a direction perpendicular to the surface of an object. Gauge pressure is the pressure relative to the local atmospheric or ambient pressure.- Definition :...

s, for example from 10 to 50 psi (70 to 350 kPa).

Further reading



  • Irrigation, 5th Edition,Engr Muhammad Irfan Khan Yousafzai, Claude H. Pair, editor, published by the Irrigation Association, 1983
  • Trickle Irrigation for Crop Production, F.S. Nakayama and D.A. Bucks, editors, published by Elsevier, 1986, ISBN 0-444-42615-9
  • S. Blass, Water in Strife and Action (Hebrew), published by Massada limited, Israel, 1973
  • Maintenance Manual, published by Jain Irrigation Systems, 1989
  • Drip and Micro Irrigation Design and Management for Trees, Vines, and Field Crops, 3rd Edition, by Charles M. Burt and Stuart W. Styles, published by the Irrigation Training and Research Center, 2007