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ARS Home » Plains Area » Bushland, Texas » Conservation and Production Research Laboratory » Soil and Water Management Research » Research » Publications at this Location » Publication #176382
Title: DRIP AND EVAPORATION

Author
item Evett, Steven - Steve
item Colaizzi, Paul
item Howell, Terry

Submitted to: Proceedings of the Central Plains Irrigation Conference
Publication Type: Review Article
Publication Acceptance Date: 1/21/2005
Publication Date: 2/16/2005
Citation: Evett, S.R., Colaizzi, P.D., Howell, T.A. 2005. Drip and evaporation. In: Proceedings of the Central Plains Irrigation Conference, February 16-17, 2005, Sterling, Colorado. p. 33-39.

Interpretive Summary: Loss of water from the soil profile through evaporation from the soil surface causes inefficient use of water in irrigated crop production. Residue management systems may reduce this evaporative loss, but cannot be used in all cropping systems. Choice of the irrigation system and its management also can reduce evaporative loss. In particular, subsurface drip irrigation (SDI) limits soil surface wetting and can lead to an overall reduction in crop water use of as much as 10%. Under limited supplies of irrigation water, this water would be beneficially transpired by the crop, resulting in improved yields and water use efficiency. The example presented shows that most of the water savings occur early in the season when crop cover is not yet complete. Because evaporation from the soil surface has a cooling effect on the soil in the root zone, irrigation methods that limit evaporation will result in smaller fluctuations in soil temperature and warmer soil temperatures overall. For some crops such as cotton, this has beneficial effects that include earlier root growth, better plant development and larger yields. Economic pressure and limited irrigation supplies from the Ogallala aquifer are two reasons that cotton production is moving northward into the northern Texas Panhandle, Oklahoma and Kansas. The advantages of SDI may mean the difference between success and failure in these areas, where cotton is marginal due to shorter and cooler growing seasons.

Technical Abstract: Loss of water from the soil profile through evaporation from the soil surface is an important contributor to inefficiency in irrigated crop production. Residue management systems may reduce this evaporative loss, but cannot be used in all cropping systems. Choice of the irrigation system and its management also can reduce evaporative loss. In particular, subsurface drop irrigation (SDI) limits soil surface wetting and can lead to an overall reduction in evapotranspiration (crop water use) of as much as 10%. The example presented shows that most of the water savings occur early in the season when crop cover is not yet complete. When water supplies are limited so that irrigation does not meet the crop need for maximum irrigation, the savings with SDI are enough to increase yields substantially. Because evaporation from the soil surface has a cooling effect on the soil in the root zone, irrigation methods that limit evaporation will result in smaller fluctuations in soil temperature and warmer soil temperatures overall. For some crops such as cotton, this has beneficial effects that include earlier root growth, better plant development and larger yield.