Agricultural Water Conservation

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Agricultural Water Conservation is a subject often studied, with several possible methods explored. One way farmers can reduce water usage is by investing in more efficient irrigation methods. Another way is by using technology to check soil moisture before irrigating, so that irrigation is only done as needed. Studies also examine whether altering the price of irrigation water will reduce agricultural water use. Another potential way to reduce water use is called deficit irrigation, which is the irrigation of crops with less water than the crop's full need.[1]

In the 11 westernmost contiguous U.S. states, 84% of freshwater withdrawals are for irrigation.[2] Therefore, a small change in water use for irrigation will make a significant change in the amount of water available for other uses.[3] Irrigation also accounts for a large amount of pollution[4][5][6] and it contributes to salinity problems.[4]

Lack of Statistical Information on Irrigation

A 2012 study noted that:

"Despite the importance of irrigation management, federal agencies do not collect comprehensive, annual data about irrigator behavior. The US Geological Survey (USGS) has published Water Use in the United States at 5-year intervals. Data are published by state and county on area irrigated and water withdrawn by method (flood, sprinkler, or micro) and source (groundwater vs surface water). USGS reports these data with long time lags."[3]

The Census of Agriculture, published every five years, collects irrigation data. However, it is distributed in a form that makes multivariate statistical analysis impossible. Therefore, it is of limited usefulness in discovering national or local trends in irrigation.

When to Irrigate

Most farmers decide on irrigation timing either by the condition of the crop or the feel of the soil (i.e. if it felt moist). The next most common way to schedule irrigation is simply based on calendar scheduling.[3][7] Some farms use more precise methods to time irrigation, such as soil moisture testing or commercial services. A 2012 study of farmers in Arizona and New Mexico found that these methods were uncommon, but to the extent that they were used, they were more common among large farms than small farms.[3] The study reported, "Adoption rates of scientific irrigation scheduling methods, such as soil or plant moisture sensing devices, computer simulations, or reports of crop evapotranspiration (ET). Fewer than 5% of growers use these methods. About 5% of irrigators rely on government or private scheduling services, however. It is possible that these intermediaries use scientific scheduling methods.

Barriers to Water Conservation

A 2012 study found that the most significant constraints to conservation are economic. Often the cost of investing in more efficient irrigation technology outweighed the benefits and there was a lack of available financing. Additionally, some farmers did not expect to stay in farming long enough to make the investment pay off.[3]

Low water costs and prohibitions on water trading are barriers to water conservation. Water is frequently subsidized and cheap, and might even be sold at a fixed rate per hectare, so water conservation may not reduce costs to irrigators.[3] In one survey of New Mexico irrigators, irrigators reported the main reason they did not conserve water was lack of ability to sell the conserved water.[8]

Additionally, regulations over water rights can serve as a disincentive to conservation. Water rights some areas such as Arizona and New Mexico, follow the ‘prior appropriation’ doctrine in which users establish water rights by putting water to 'beneficial use' (i.e. agriculture and mining).[9][10] If those with water rights voluntarily reduce water use, they may lose the rights to that water in the future. This creates a disincentive to conserve.[11]

Can Water Conservation in Irrigation Lead to Increased Water Use

The notion that water conservation leads to increased water use bases its argument in part on the notion that irrigation water not lost through evapotranspiration (ET) returns to the water system from which it was taken.[12] Drip irrigation water is delivered directly to the plants' root zones, used, and lost through ET while increasing crop yield, but it does not percolate into the soil to recharge groundwater or run off to recharge surface water.

Articles and resources

Related SourceWatch articles


  1. Fereres, E., & Soriano, M. A. (2007). Deficit irrigation for reducing agricultural water use. Journal of Experimental Botany, 58(2), 147–159.
  2. Hutson S, Barber N, Kenny J, Linsey K, Lumia D, Maupin M. 2005. Estimated Use of Water in the United States in 2000. USGS Circular 1268. US Geological Survey: Reston, Va.
  3. 3.0 3.1 3.2 3.3 3.4 3.5 Frisvold, G. B., & Deva, S. (2012). Farm Size, Irrigation Practices, and Conservation Program Participation in the Us Southwest. Irrigation and Drainage, 61(5), 569–582.
  4. 4.0 4.1 Council for Agricultural Science and Technology (CAST). 1992. Water Quality: Agriculture’s Role. Task Force Report 120, Ames, Iowa.

  5. National Research Council (NRC). 1996. A New Era for Irrigation. National Academy Press: Washington, DC.
  6. US Environmental Protection Agency (EPA). 1998. National Water Quality Inventory: 1996 Report to Congress. EPA841-R-97-008. Office of Water: Washington, DC.
  7. Leib B, Hattendorf M, Elliott T, Matthews G. 2002. Adoption and adaptation of scientific irrigation scheduling: trends from Washington, USA as of 1998. Agricultural Water Management 55: 105–120.
  8. Ward FA, Michelsen AM, DeMouche L. 2007. Barriers to water conservation in the Rio Grande Basin. Journal of the American Water Resources Association 43: 237–253.
  9. Fleming WM, Hall GE. 2000. Water conservation incentives for New Mexico: policy and legislative alternatives. Natural Resources Journal 40: 69–91.

  10. Pearce MJ. 2006. Balancing competing interests: the history of state and federal water laws. In Arizona Water Policy: Management Innovations in an Urbanizing, Arid Region, Colby BG, Jacobs KL (eds). Resources for the Future Press: Washington, DC.
  11. Ward FA, Michelsen AM, DeMouche L. 2007. Barriers to water conservation in the Rio Grande Basin. Journal of the American Water Resources Association 43: 237–253.
  12. Ward, F. A., & Pulido-Velazquez, M. (2008). Water conservation in irrigation can increase water use. Proceedings of the National Academy of Sciences, 105(47), 18215–18220.

External resources

External articles




  • Nair, S., Johnson, J., & Wang, C. (2013). Efficiency of Irrigation Water Use: A Review from the Perspectives of Multiple Disciplines. Agronomy Journal, 105(2), 351–363.