Irrigation statistics

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This page shows statistical data on irrigation of agricultural lands worldwide.
Irrigation is the artificial abstraction of water from a source followed by the distribution of it at scheme level aiming at application at field level to enhance crop production when rainfall is scarce.

Contents

Irrigated area

The appended table gives an overview of irrigated areas in the world in 2003 [1]
Only the countries with more than 10 million ha of irrigated land are mentioned.

Area (106 ha)  
India57
China54
Pakistan 19
Asia (*)188
United States22
World 277

(*) Including India, China and Pakistan

There are 4 countries with 5 to 10 million ha irrigated land: Iran (7.7), Mexico (6.3), Turkey (5.1), and Thailand (5.0).

The 16 countries with 2 to 5 million ha irrigated land are: Bangladesh (4.7), Indonesia (4.5), Russia (4.5), Uzbekistan (4.3), Spain (3.8), Brazil (3.5), Iraq (3.5), Egypt (3.4), Romania (3.0), Vietnam (3.0), Italy (2.8), France (2.6), Japan (2.6), Australia (2.6), Ukraine (2.3), and Kazakhstan (2.1)

Area per application method at field level

94% of the application methods of irrigation water at field level is of the category surface irrigation, [1] whereby the water is spread over the field by gravity.

Of the remaining 6%, the majority is irrigated by methods requiring energy, expensive hydraulic pressure techniques and pipe systems like sprinkler irrigation and drip irrigation, for the major part in the USA. The source of irrigation water in these cases often is groundwater from aquifers. However, the exploitation of aquifers can also be combined with surface irrigation at field level.

Basin irrigation for a rice crop Campos de arroz en el Bajo Piura 1.jpg
Basin irrigation for a rice crop
Terraced rice fields in Yunnan province, China. Terrace field yunnan china denoised.jpg
Terraced rice fields in Yunnan province, China.
Furrow irrigation Riego por surcos.JPG
Furrow irrigation

In relatively small areas one applies subirrigation whereby the water infiltrates into the soil below the soil surface from pipes or ditches. This category includes tidal irrigation used in the lower part of rivers where the tidal influence is felt by permitting the river water to enter ditches at high tide and allowing it to infiltrate from there into the soil [2]

In relative rare cases one uses labor-intensive methods like irrigation with watering-cans and by filling dug-in porous pots (pitcher irrigation) from where the water enters the soil by capillary suction.

Surface irrigation can be divided into the following types, based on the method by which water is spread over the field after it has been admitted through the inlet: [3]

The first four forms of irrigation come in the category of flood-irrigation, because the entire surface of the cropped area is wetted, whereas with furrow irrigation, the surface of the ridges remain dry. The irrigation of sloping fields is called flow irrigation as the water on the surface does not come to a stand still and the stream entering the field has to be cut back before the wetting front reaches the end of the field to avoid runoff losses.

Areal growth

From 1955 to 1975 the annual growth of the irrigated area was almost 3%. [7] From 1970 to 1982 the growth rate was some 2% per year, and from 1983 to 1994 about 1.3% per year. The growth rate of irrigated area is decreasing.

The following table shows the irrigation development in the world between 1955 and 1983, distinguishing developed from developing countries: [8]

19551983Increase
  106 ha   % of WT  106 ha   % of WT  106 ha   % of 1955
Developed countries2823612933118
Developing countries9377152715963
World total (WT)1211002131009276
India+Pakistan332755262267
China312645211445

The developed countries witnessed a relatively greater increase than the developing nations.

Water use

Irrigation schemes in the world use about 3 500 km3 water per year, of which 74% is evaporated by the crops. [7] This is some 80% of all water used by mankind (4 400 km3 per year).
The water used for irrigation is roughly 25% of the annually available water resources (14 000 km3) and 9% of all annual river discharges in the hydrological cycle.
River discharges occur for the major part in regions with humid climates, far removed from the regions with (semi)arid climates, where irrigation water is most needed. Compared to the 8 600 km3 of annual river discharge in the drier climates only, the yearly water use for irrigation is 40%

irrigation
use		all usesusable
resources		total supply
Quantity of water in km3/year3 5004 40014 00040 000
Irrigation as a percentage (%)80100259

Of the total irrigated area worldwide 38% is equipped for irrigation with groundwater, especially in India (39 million ha), China (19 million ha) and the United States of America (17 million ha). [9] Total consumptive groundwater use for irrigation is estimated as 545 km3/year. Groundwater use in irrigation leads in places to exploitation of groundwater at rates above groundwater recharge and depletion of groundwater reservoirs.

Economical significance

The irrigated area occupies worldwide about 16% of the total agricultural area, but the crop yield is roughly 40% of the total yield. [7] Hence, the productivity of irrigated land is 3.6 times that of unirrigated land. The monetary value of the yield of irrigated crops is some 6.6 times that of unirrigated crops. In irrigated land one grows crops with higher market values.

Related Research Articles

Irrigation Artificial application of water to land

Irrigation is the agricultural process of applying controlled amounts of water to land to assist in the production of crops, as well as to grow landscape plants and lawns, where it may be known as watering. Agriculture that does not use irrigation but instead relies only on direct rainfall is referred to as rain-fed. Irrigation has been a central feature of agriculture for over 5,000 years and has been developed independently by many cultures across the globe.

Aquifer Underground layer of water-bearing permeable rock

An aquifer is an underground layer of water-bearing permeable rock, rock fractures or unconsolidated materials.

Soil salinity Salt content in the soil

Soil salinity is the salt content in the soil; the process of increasing the salt content is known as salinization. Salts occur naturally within soils and water. Salination can be caused by natural processes such as mineral weathering or by the gradual withdrawal of an ocean. It can also come about through artificial processes such as irrigation and road salt.

Water table Top of a saturated aquifer, or where the water pressure head is equal to the atmospheric pressure

The water table is the upper surface of the zone of saturation. The zone of saturation is where the pores and fractures of the ground are saturated with water. It can also be simply explained as the depth below which the ground is saturated.

Punata Province Province in Cochabamba, Bolivia

Punata is a province almost in the middle of the Cochabamba Department, Bolivia, located about 45 km south of the city of Cochabamba. Its capital is Punata. The province is limited to the north by the Chapare Province, to the north-east by the Tiraque Province, to the east by the Arani Province, to the south-east by the Mizque Province, to the south by the Esteban Arze Province and to the west by the Germán Jordán Province.

Acid sulfate soils are naturally occurring soils, sediments or organic substrates that are formed under waterlogged conditions. These soils contain iron sulfide minerals or their oxidation products. In an undisturbed state below the water table, acid sulfate soils are benign. However, if the soils are drained, excavated or exposed to air by a lowering of the water table, the sulfides react with oxygen to form sulfuric acid.

Watertable control is the practice of controlling the height of the water table by drainage. Its main applications are in agricultural land and in cities to manage the extensive underground infrastructure that includes the foundations of large buildings, underground transit systems, and extensive utilities.

Soil salinity control

Soil salinity control relates to controlling the problem of soil salinity and reclaiming salinized agricultural land.

Well drainage means drainage of agricultural lands by wells. Agricultural land is drained by pumped wells to improve the soils by controlling water table levels and soil salinity.

Runoff model (reservoir)

A runoff model is a mathematical model describing the rainfall–runoff relations of a rainfall catchment area, drainage basin or watershed. More precisely, it produces a surface runoff hydrograph in response to a rainfall event, represented by and input as a hyetograph. In other words, the model calculates the conversion of rainfall into runoff.
A well known runoff model is the linear reservoir, but in practice it has limited applicability.
The runoff model with a non-linear reservoir is more universally applicable, but still it holds only for catchments whose surface area is limited by the condition that the rainfall can be considered more or less uniformly distributed over the area. The maximum size of the watershed then depends on the rainfall characteristics of the region. When the study area is too large, it can be divided into sub-catchments and the various runoff hydrographs may be combined using flood routing techniques.

Leaching (agriculture) Loss of water-soluble plant nutrients from soil due to rain and irrigation

In agriculture, leaching is the loss of water-soluble plant nutrients from the soil, due to rain and irrigation. Soil structure, crop planting, type and application rates of fertilizers, and other factors are taken into account to avoid excessive nutrient loss. Leaching may also refer to the practice of applying a small amount of excess irrigation where the water has a high salt content to avoid salts from building up in the soil. Where this is practiced, drainage must also usually be employed, to carry away the excess water.

Surface irrigation

Surface irrigation is 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.

An agricultural drainage system is a system by which water is drained on or in the soil to enhance agricultural production of crops. It may involve any combination of stormwater control, erosion control, and watertable control.

Environmental effects of irrigation

The environmental effects of irrigation relate to the changes in quantity and quality of soil and water as a result of irrigation and the subsequent effects on natural and social conditions in river basins and downstream of an irrigation scheme. The effects stem from the altered hydrological conditions caused by the installation and operation of the irrigation scheme.

A leaching model is a hydrological model by which the leaching with irrigation water of dissolved substances, notably salt, in the soil is described depending on the hydrological regime and the soil's properties.
The model may describe the process (1) in time and (2) as a function of amount of water applied.
Leaching is often done to reclaim saline soil or to conserve a favorable salt content of the soil of irrigated land as all irrigation water contains salts.

Irrigation is the artificial exploitation and distribution of water at project level aiming at application of water at field level to agricultural crops in dry areas or in periods of scarce rainfall to assure or improve crop production.
This article discusses organizational forms and means of management of irrigation water at project (system) level.

Drainage equation

A drainage equation is an equation describing the relation between depth and spacing of parallel subsurface drains, depth of the watertable, depth and hydraulic conductivity of the soils. It is used in drainage design.

Irrigation in Iran covers 89,930 km2 making it the fifth ranked country in terms of irrigated area.

Salt tolerance of crops

Salt tolerance of crops is the maximum salt level a crop tolerates without losing its productivity while it is affected negatively at higher levels. The salt level is often taken as the soil salinity or the salinity of the irrigation water.

Water use in alluvial fans refers to irrigation systems using the water resources in alluvial fans, mainly river floods and groundwater recharged by infiltration of rain or river water, to enhance the production of agricultural crops.

References

  1. 1 2 International Commission on Irrigation and Drainage (ICID). Download PDF file : http://www.icid.org/imp_data.pdf
  2. ↑ Improvement of tidal irrigation, drainage and reclamation of salinized land under date palms in Abadan Island, Iran. 20 pp. Consultancy report. Download from web page : , or directly as PDF :
  3. ↑ Wynn R. Walker, 2007. Irrigation: Surface. In: Stanley W. Trimble (Ed.), Encyclopedia of Water Science, Vol I, p. 678-683. On line:
  4. ↑ "Library on spate irrigation". Archived from the original on 2009-12-15. Retrieved 2010-08-21.
  5. ↑ ILRI, 1982. Modern interferences in traditional water resources in Baluchistan. In: Annual Report 1982, pp. 23-34. ILRI, Wageningen, The Netherlands. Reprinted in Water International 9 (1984), pp. 106- 111. Elsevier Sequoia, Amsterdam. Also reprinted in Water Research Journal (1983) 139, pp. 53-60. Download from : , under nr. 10, or directly as PDF :
  6. ↑ R.J. Oosterbaan, L.F. Kortenhorst, and L.H.Sprey, 1987. Flood-recession cropping in the molapo's of the Okavango Inland Delta, Botswana. Published in Annual Report 1986, p. 8 – 19. International Institute for Land Reclamation and Improvement (ILRI), Wageningen, The Netherlands. On line:
  7. 1 2 3 Bruce Sundquist, 2007. Chapter 1- Irrigation overview. In: The earth's carrying capacity, Some related reviews and analysis. On line : "Archived copy". Archived from the original on 2012-02-17. Retrieved 2012-02-17.{{cite web}}: CS1 maint: archived copy as title (link)
  8. ↑ Effectiveness and Social/Environmental Impacts of Irrigation Projects: a Review. In: Annual Report 1988, International Institute for Land Reclamation and Improvement (ILRI), Wageningen, The Netherlands, pp. 18 - 34 . Download from web page : , under nr 10, or from : , under nr. 6, or directly as PDF :
  9. ↑ S. Siebert, J. Burke, J. M. Faures, K. Frenken, J. Hoogeveen, P. Döll, and F. T. Portmann (2010). Groundwater use for irrigation – a global inventory. In: Hydrology and Earth System Sciences. See also the PDF file :
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