Today @ Colorado State has been replaced by SOURCE. This site exists as an archive of Today @ Colorado State stories between January 1, 2009 and September 8, 2014.

Research / Discovery

Increasing water use efficiency for agriculture

February 26, 2010
By Joel Schneekloth

The combination of drought, groundwater depletion, and increasing urban competition for water has created water shortages for irrigated agriculture in Colorado and is driving the need to increase water use efficiency.

The Prarie Waters Project pipeline will deliver 3.3 billion gallons of water annually to the city of Aurora. Photo courtesy of Aurara Water and Colorado Water newsletter.

Urban competition for water

A statewide water supply survey predicts that 428,000 irrigated farm acres may be converted to dryland cropping or pasture within the next 15 years, mostly due to transfer of water from agricultural uses to meet the water needs associated with population growth.

Water conservation options other than complete land fallowing are desirable because of the potential economic and environmental concerns associated with conversion to dryland. One approach to reducing consumptive use of irrigation water is adoption of limited irrigation cropping systems, in which less water is applied than is required to meet the full evapotranspiration demand of the crop.

Hybrid of full irrigation

Crops managed with limited irrigation experience water stress and have reduced yields compared to full irrigation, but management is employed to maximize the efficient use of the limited irrigation water applied. These systems are a hybrid of full irrigation and dryland cropping systems and are currently of great interest to Colorado farmers. Successful limited irrigation systems are based on:

  • managing crop water stress
  • timing irrigation to correspond to critical growth stages for specific crops
  • maximizing water use efficiency by improving precipitation capture and irrigation efficiency
  • matching crop rotations with local patterns of precipitation and evaporative demand

Large-scale demonstration project in southeast Colo.

This image shows a strip of irrigated wheat that is phosphorous deficient. Photo courtesy of Joel Schneekloth and Colorado Water newsletter.

A large-scale demonstration site was developed in 2006 near Burlington, Colo., on a silt loam soil. This field is center pivot irrigated. Alternative water management strategies were studied at this site within a 4-year crop rotation of corn-sunflower-soybean and winter wheat.

The study looked at full irrigation management, an average allocation of 10 inches per year, and an intermediate irrigation management strategy that limits water applied between that of full irrigation and allocation management.

The primary goals of this project, which was funded by the Colorado NRCS Conservation Innovation Grant and the Republican River Water Conservation District, were to look at alternative water management strategies with cropping systems to decrease water use within the Republican Basin, due to compact-related issues with Kansas and Nebraska.

Irrigation water can be reduced and economical yields obtained

Limited irrigation of crops is management intensive and is potentially more risky than full irrigation management. However, research and demonstration projects in Colorado have successfully shown that irrigation water can be reduced and economical yields obtained.

Alternative crops such as sunflower and soybeans can reduce the amount of irrigation needed as compared to corn. Education and marketing will play an important factor in the acceptance of these crops for irrigation conservation.Keeping irrigated acres irrigated or transferring the saved water to higher income sources will increase the economic opportunity of limiting water.

Decling water resources and litigation may force changes

Under current water law and regulations, water management such as limited water is not practical in years other than water short years in ditch and reservoir systems. In groundwater management areas, declining water resources and compact litigation may force limited irrigation changes with less water in the future.

Excerpt from story originally published in the January/Febuary 2010 newsletter of the Water Center of Colorado State University Colorado Water. The author, Joel Schneekloth, is a CSU Extension Specialist.