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Encyclopedia > Irrigated land
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Irrigating cotton fields
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Irrigation in the Heart of the Sahara

Irrigation (in agriculture) is the replacement or supplementation of rainfall with water from another source in order to grow crops. In contrast, agriculture that relies only on direct rainfall is sometimes referred to as dryland farming. The Sahara is the worlds second largest desert (second to Antarctica), over 9,000,000 km² (3,500,000 mi²), located in northern Africa and is 2. ... Farming, ploughing rice paddy, in Indonesia Agriculture is the process of producing food, feed, fiber and other desired products by cultivation of certain plants and the raising of domesticated animals ( livestock). ... Rain falling Rain on an umbrella Rain is a form of precipitation, as are snow, sleet, hail, and dew. ... Dryland farming is an agricultural technique for cultivating land which receives little rainfall. ...

Contents

How it works in general

The water source for irrigation may be a nearby or distant body of liquid or frozen water such as a river, spring, lake, aquifer, well, or snowpack. Depending on the distance of the source and the seasonality of rainfall, the water may be channelled directly to the agricultural fields or stored in reservoirs or cisterns for later use. In addition, the "harvesting" of local rain that falls on the roofs of buildings or on nearby unfarmed hills and its use to supplement the rain that falls directly on farmed fields also involves irrigation. Drinking water This article focuses on water as we experience it every day. ... For the Second World War frigate class, see River class frigate The Murray River in Australia A waterfall on the Ova da Fedoz, Switzerland A river is a large natural waterway. ... A spring is a place where an underground stream flows out of the ground. ... Lake Clearwater, Ontario, Canada A lake is a large body of water, usually fresh water, surrounded by land. ... An aquifer is an underground layer of water-bearing permeable rock, or permeable mixtures of unconsolidated materials ( gravel, sand, silt, or clay) (see also groundwater). ... For the pioneering virtual community, see The WELL. A well is an artificial boring in the earth through which water, oil or gas can be obtained. ... A reservoir (French: réservoir) is an artificial lake created by flooding land behind a dam. ... A cistern (Middle English cisterne, from Latin cisterna, from cista, box, from Greek kistê, basket) is a receptacle for holding liquids, usually water. ...


Various types of irrigation techniques differ in how the water obtained from the source is distributed within the field. In general, the goal is to supply the entire field uniformly with water, so that each plant has the amount of water it needs, neither too much nor too little.


Types of irrigation

Ditch (Furrow) irrigation

The plants are grown in somewhat raised beds or listed rows, and the water is distributed throughout the field via canals, unlined ditches, or furrows, between the rows or beds. Depending on economic and physical factors such as the size of the field, the types of technology available, and the cost of manpower, the ditches can be dug with hand tools, turned with a plow pulled by an animal or tractor, or precisely fashioned using laser-guided instruments. Water can be transported to the furrows via rigid gated plastic or aluminum pipe, layflat plastic with holes punched at each furrow, concrete or plastic lined ditches, or unlined ditches. Where ditches are used, siphon tubes are generally used to move water from the main ditch to the furrow. When pipes are used, water flow can be controlled by turning it on or off at the local source or by using automatic or manually controlled gates to shunt it from one set of ditches to another. Unless the field is small or very level, parts of it may suffer from water-logging while other parts may be too dry. Depending on heat, wind, and soil permeability, much water may be lost before it can benefit the plants. Automatic valves, also known as surge valves, can increase the efficiency of furrow irrigation because they alternately wet the furrows and allow the soil infiltration rate to slow prior to using the furrow for actual irrigation. Divisions Green algae land plants (embryophytes) non-vascular embryophytes Hepatophyta - liverworts Anthocerophyta - hornworts Bryophyta - mosses vascular plants (tracheophytes) seedless vascular plants Lycopodiophyta - clubmosses Equisetophyta - horsetails Pteridophyta - true ferns Psilotophyta - whisk ferns Ophioglossophyta - adderstongue ferns seed plants (spermatophytes) †Pteridospermatophyta - seed ferns Pinophyta - conifers Cycadophyta - cycads Ginkgophyta - ginkgo Gnetophyta - gnetae Magnoliophyta - flowering... Categories: Water-transport stubs | Canals | Water transport ... A modern farm tractor. ... For alternative meanings see laser (disambiguation). ... The term plastics covers a range of synthetic or semi-synthetic organic condensation or polymerization products that can be molded or extruded into objects or films or fibers. ... General Name, Symbol, Number aluminium, Al, 13 Chemical series poor metals Group, Period, Block 13 (IIIA), 3, p Density, Hardness 2700 kg/m3, 2. ... The word pipe can refer to: The basic cylindrical pipe shape a tubular man-made channel, generally round in cross section, in steel or concrete for transporting or guiding a fluid substance see plumbing and pipeline transport used in construction as column, truss element or space frame in mechanical engineering... This article is about the construction material. ... Heat (abbreviated Q, also called heat change) is the transfer of thermal energy between two bodies which are at different temperatures. ... For the 1928 film, see The Wind. ... For the heavy metal band see Soil (band) Soil is the layer of minerals and organic matter, in thickness from centimetres to a metre or more, on the land surface. ... In geology, permeability is a measure of the ability of a material (typically, a rock) to transmit fluids through it. ...


Once common in the U.S., many ditch irrigation systems have been replaced because of high labor costs and increasing demands on water resources. Furrow irrigation also has a tendency to raise the water table in some areas and cause soil salination, requiring drainage. These types of systems are still common in other parts of the world. Water resources are sources of water that are useful to human beings for drinking, recreation, irrigation, livestock production, industry, etc. ... Soil salination results from the accumulation of free salts to such an extent that it leads to degradation of soils and vegetation. ... Many agricultural soils need drainage to improve production or to manage water supplies. ...


Terracing

Large steps are cut into hillsides and supported by stone or concrete walls. The level parts are used as garden plots or small fields. As water flows down the hillside it is channelled to each plot (probably most often by ditch irrigation). Terracing is usually very labor-intensive, since the fields are small and access to them may be steep and narrow (so it's hard to mechanize the work). In addition, the walls need constant maintenance, especially in rainy climates. However, terracing does allow steep mountainsides to be used to grow plants (although it may be more cost effective to use them only for animal pasturage). Rock is a naturally occurring aggregate of minerals and/or mineraloids. ... This article is about the construction material. ... This article is about structural, boundary and retaining walls. ...


Overhead (sprinkler) irrigation

Overhead irrigation of in
Overhead irrigation of blueberries in Plainville, New York

In overhead or sprinkler irrigation, water is piped to one or more central locations within the field and distributed by overhead high-pressure sprinklers or guns or by lower-pressure sprays. A system utilizing sprinklers, sprays, or guns mounted overhead on permanently installed risers is often referred to as a solid-set irrigation system. Some sprinklers can also be hidden below ground level, if aesthetics is a concern, and pop up in response to increased water pressure. This type of system is commonly used in lawns, golf courses, cemeteries, parks, and other turf areas. For other uses, see Blueberry (disambiguation). ...


Sprinklers that spray in a fixed pattern are generally called sprays or spray heads. Sprays are not usually designed to operate at pressures above 30 psi (200 kPa), due to misting problems that may develop, while higher pressure sprinklers that rotate are usually called rotors. Rotors are usually driven by a ball drive, gear drive, or impact mechanism. Rotors can be designed to rotate in a full or partial circle. Guns are similar to rotors, except that they generally operate at very high pressures of 40 to 130 psi (275 to 900 kPa) and flows of 50 to 1200 gal/min (3 to 76 L/s), usually with nozzle diameters in the range of 0.5 to 1.9 inches (10 to 50 mm). Guns are used not only for irrigation, but also for industrial applications such as dust suppression and logging. Psi (Ψ ψ) is a letter of the Greek alphabet. ... Psi (Ψ ψ) is a letter of the Greek alphabet. ... For another article about a different type of logging, see data logging. ...


Sprinklers may also be mounted on movable platforms connected to the water source by a hose. At the high-tech end, computerized, automatically moving wheeled systems may irrigate large areas unattended. At the low end, such as in a small greenhouse or landscape, a person may be watering each plant individually with a hose end sprinkler or even a watering can.


One drawback of overhead irrigation is that much water can be lost because of high winds or evaporation, and irrigating the entire field uniformly can be difficult or tedious if the system is not properly designed. Water remaining on plants' leaves may promote fungal and other diseases. If fertilizers are included in the irrigation water, plant leaves can be burned, especially on hot, sunny days.


Overhead irrigation is generally the best solution for watering lawns and golf courses, although drip irrigation is gaining in popularity in some lawn applications. (See also center pivot irrigation.) Drip irrigation is an irrigation method that applies water slowly to the roots of plants, by depositing the water either on the soil surface or directly to the root zone. ... Sahara Irrigation (in agriculture) is the replacement or supplementation of rainfall with water from another source in order to grow crops. ...


Manually assembled systems of piping that are broken down to permit tillage and harvesting are sometimes called "hand set" or "hand move pipe". These are also commonly used on athletic fields where permanently installed sprinklers or outlets are not desired or where lower initial costs are a factor. Tillage (American English), or cultivation (UK) is the agricultural preparation of the soil to receive seeds. ... This article is about gathering crops. ...

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The hub of a center-pivot irrigation system.

Center pivot irrigation

Center pivot irrigation is a form of overhead irrigation consisting of several segments of pipe (usually galvanized steel or aluminum) joined together and supported by trusses, mounted on wheeled towers with sprinklers positioned along its length. The system moves in a circular pattern and is fed with water from the pivot point at the center of the arc. These systems are common in parts of the United States where terrain is flat. Most center pivot systems now have drops hanging from a u-shaped pipe called a gooseneck attached at the top of the pipe with sprinkler heads that are positioned a few feet (at most) above the crop, thus limiting evaporative losses. Drops can also be used with drag hoses or bubblers that deposit the water directly on the ground between crops. The crops are planted in a circle to conform to the center pivot. This type of system is known as LEPA (Low Energy Precision Application). In medicine, a truss is a kind of surgical appliance, particularly one used for hernia patients. ...

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Pivot irrigation in progress

Originally, most center pivots were water powered. These were replaced by hydraulic systems (T-L) and electric motor driven systems (Lindsay, Reinke, Valley). Most systems today are driven by an electric motor mounted at each tower.


Center pivot equipment can also be configured to move in a straight line, where the water is pulled from a central ditch. In this scenario, the system is called a linear move irrigation system.


Lateral move (Side roll, Wheel line) irrigation

A series of pipes, each with a wheel of about 1.5 m diameter permanently affixed to its midpoint and sprinklers along its length, are coupled together at one edge of a field. Water is supplied at one end using a large hose. After sufficient water has been applied, the hose is removed and the remaining assembly rotated either by hand or with a purpose-built mechanism, so that the sprinklers move 10m across the field. The hose is reconnected. The process is repeated until the opposite edge of the field is reached.


This system is less expensive to install than a center pivot, but much more labor intensive to operate, and it is limited in the amount of water it can carry. Most systems utilize 4 or 5 inch diameter aluminum pipe. One feature of a lateral move system is that it consists of sections that can be easily disconnected. They are most often used for small or oddly-shaped fields, such as those found in hilly or mountainous regions, or in regions where labor is inexpensive.


Drip, or trickle, irrigation

See main article at drip irrigation

Water is delivered at or near the root zone of plants, drop by drop. This type of system can be the most water-efficient method of irrigation, if managed properly, since evaporation and runoff are minimized. In modern agriculture, drip irrigation is often combined with plastic mulch, further reducing evaporation, and being also the means of delivery of fertilizer. The process is known as fertigation. Drip irrigation is an irrigation method that applies water slowly to the roots of plants, by depositing the water either on the soil surface or directly to the root zone. ... For other meanings of root, see Root (disambiguation). ... Plastic mulch is a product used to suppress weeds and conserve water in crop production and landscaping. ...


Deep percolation, where water moves below the root zone, can occur if a drip system is operated for too long of a duration. Drip irrigation methods range from very high-tech and computerized to low-tech and relatively labor-intensive. Lower water pressures are usually needed than for most other types of systems, with the exception of low energy center pivot systems and surface irrigation systems, and the distribution can be adjusted for uniformity throughout a field or for precise water delivery to individual plants in a landscape containing a mix of plant species. Although it is difficult to regulate pressure on steep slopes, the field does not have to be level. High-tech solutions involve precisely calibrated emitters located along lines of tubing that extend from a computerized set of valves. Both pressure regulation and filtration to remove particles are important. The tubes are usually black (or buried under soil or mulch) to prevent the growth of algae. But drip irrigation can also be as low-tech as a porous clay vessel sunk into the soil and occasionally filled from a hose or bucket. Subsurface drip irrigation has been used successfully on lawns, but it is more expensive than a more traditional sprinkler system. Surface drip systems are not cost-effective (or esthetically pleasing) for lawns and golf courses. A valve is a mechanical device that regulates the flow of fluids (either gases, fluidised solids, slurries or liquids) by opening, closing, or partially obstructing various passageways. ... For the town in the United States, see Clay, New York. ... Drip irrigation is an irrigation method that applies water slowly to the roots of plants, by depositing the water either on the soil surface or directly to the root zone. ... This article is about the sport of golf. ...


Subirrigation

Used in commercial greenhouse production, usually for potted plants, water is delivered from below, absorbed upwards, and the excess collected for recycling. Typically, a solution of water and nutrients floods a container or flows through a trough for a short period of time, 10-20 minutes, and is then pumped back into a holding tank for reuse. Subirrigation requires fairly sophisticated, expensive equipment and management. Advantages are water and nutrient conservation, and labor-saving through lowered system maintenance and automation. It is similar in principle and action to subsurface drip irrigation. The same concept of subsurface flooding and drainage is also being experimented with as an outdoor subirrigation method. This article needs cleanup. ... A greenhouse in Saint Paul, Minnesota. ... In agriculture, subirrigation is a method of irrigation used in commercial greenhouse operations. ... Automation (ancient Greek: = self dictated) or Industrial Automation is the use of computers to control industrial machinery and processes, replacing human operators. ...


History of irrigation

Evidence exists of irrigation in Mesopotamia and Egypt as far back as the 6th millennium BC. Mesopotamia ( Greek: Μεσοποταμία, translated from Old Persian Miyanrudan the Land between the Rivers or the Aramaic name Beth-Nahrin two rivers) is a region of Southwest Asia. ... The Arab Republic of Egypt, commonly known as Egypt, (in Arabic: مصر, romanized Mişr or Maşr, in Egyptian dialect) is a republic mostly located in northeastern Africa. ... (7th millennium BC – 6th millennium BC – 5th millennium BC – other millennia) Events c. ...


There is also evidence of ancient Egyptian pharaohs of the twelfth dynasty using the natural Lake of the Fayûm as a reservoir to store surpluses of water for use during the dry seasons, as the lake swelled annually as caused by the annual flooding of the Nile. Ancient visitors reported the appearance of "an artificial excavation, as reported by classic geographers and travellers" (CATHOLIC ENCYCLOPEDIA: Egypt: I. GENERAL DESCRIPTION: Flora and Agriculture (http://www.newadvent.org/cathen/05329b.htm)). Map of Ancient Egypt Ancient Egypt was the civilization of the Nile Valley between about 3000 BC and the conquest of Egypt by Alexander the Great in 332 BC. As a civilization based on irrigation it is the quintessential example of an hydraulic empire. ... This article refers to the historical Pharaoh. ... The chronology of the Twelfth dynasty is the most stable of any period before the New Kingdom. ... There is also Nile, a death metal band from South Carolina, USA. The Nile in Egypt Length 6 695 km Elevation of the source 1 134 m Average discharge 2 830 m³/s Area watershed 3 400 000 km² Origin Africa Mouth the Mediterranean Basin countries Uganda - Sudan - Egypt The... A geographer is a scientist whose area of study is geography, the study of the physical environment and human habitat. ... A traveller (American English traveler) is a person or an object travelling between two or more locations. ...


By the middle of the 20th century, the advent of diesel and electric motors led for the first time to systems that could pump groundwater out of major aquifers faster than it was recharged. This can lead to permanent loss of aquifer capacity, decreased water quality, ground subsidence, and other problems. The future of food production in such areas as the North China Plain, the Punjab, and the Great Plains of the US is threatened. (19th century - 20th century - 21st century - more centuries) Decades: 1900s 1910s 1920s 1930s 1940s 1950s 1960s 1970s 1980s 1990s As a means of recording the passage of time, the 20th century was that century which lasted from 1901–2000 in the sense of the Gregorian calendar (1900–1999 in the... Groundwater is any water found below the land surface. ... An aquifer is an underground layer of water-bearing permeable rock, or permeable mixtures of unconsolidated materials ( gravel, sand, silt, or clay) (see also groundwater). ... The North China Plain (华北平原 Hua2bei3 Ping2yuan2) also called the Middle Plain (中原 Zhong1yuan2), is made of the deposits of the Huang He (Yellow River) and is the largest alluvial plain of eastern Asia. ... Punjab, 1903 Punjab Province, 1909 The Punjab (sometimes spelt Panjab) is a region straddling the border between India and Pakistan. ... The Great Plains states. ...


Problems in irrigation

  • Competition for surface water rights.
  • Depletion of underground aquifers.
  • Ground subsidence (e.g. New Orleans, Louisiana)
  • Buildup of toxic salts on soil surface in areas of high evaporation.

New Orleans (French: Nouvelle-Orléans) is the largest city in the state of Louisiana, United States of America. ...

Related topics

An aquifer is an underground layer of water-bearing permeable rock, or permeable mixtures of unconsolidated materials ( gravel, sand, silt, or clay) (see also groundwater). ... Evapotranspiration (ET) is the sum of evaporation and plant transpiration. ... Hydrogeology (hydro- meaning water, and -geology meaning the study of rocks) is the part of hydrology that deals with the distribution and movement of groundwater in the soil and rocks of the Earths crust (commonly in Aquifers). ... Groundwater is any water found below the land surface. ... A rice paddy in Japan A paddy field is a flooded parcel of farmland for growing rice (from the Malaysian word padi, a noun meaning growing rice). Paddy fields are a typical feature of rice-growing countries of East and Southeast Asia, such as China, Thailand, Korea, Japan, Vietnam, Indonesia... A qanat, also known as karez, is a farming technology known to have developed in ancient Persia, and then spread to other cultures, especially along the Silk Road. ...

External links


  Results from FactBites:
 
Using Satellite Imagery to Map Irrigated Lands (4025 words)
Additionally, a comparison was made between the amount and location of irrigated land determined in the early 1980's (Thelin and Heimes, 1987) with estimates made from the 1992 data to determine changes in the amount and location of irrigated land.
The minimum and maximum DN values of the irrigated pixels and those of the nonirrigated pixels were used in a conditional statement model to threshold all the irrigated agriculture into one class and all other nonirrigated agriculture into a separate class.
The total amount of irrigated land calculated from the 1980 RASA data was 13.7 million acres compared to the 13 million acres calculated from the 1992 imagery, a decrease of approximately 5 percent.
Department of Revenue - State of Montana (1628 words)
All agricultural land, including grazing land, in a specified irrigation district where the land is designated as irrigable, with shares of water appurtenant to such land, shall be classified as irrigated, regardless of whether the water is actually applied or not applied to the land.
Land that is irrigated only during high water may be classified according to use, but it should carry a higher grade to reflect the occasional extra water and increased production.
Lands on which the native vegetation, non-irrigated alfalfa or other domestic varieties are cut for hay yearly or a majority of the time over a period of years.
  More results at FactBites »

 
 

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