ARS | Publication request: Determination of Crop Coefficients and Water Use of Corn, Spinach and Onion

Submitted to: Asa-Cssa-Sssa Proceedings
Publication Acceptance Date: May 3, 2004
Publication Date: October 5, 2004
Citation: Piccinni, G., Kolenda, K.A., Marek, T.H., Dusek, D.A., Howell, T.A., Leskovar, D.I. 2004. Determination Of Crop Coefficients And Water Use Of Corn, Spinach And Onion. [cd-Rom]. Asa-Cssa-Sssa, Seattle, Wa. Annual Meeting Abstracts 2004.

Technical Abstract: Lysimeters are used to measure real time water use during the growing season. By relating the water use of a specific crop to a well-watered reference crop such as alfalfa or grass (ETo), crop coefficients(Kc) can be developed to assist in predicting accurate crop needs using available meteorological data. Reference evapotranspiration can be obtained from several weather networks, however without crop coefficients for specific crops, this information is only useful for grass. Three weighing lysimeters, consisting of undisturbed 1.5 m x 2.0 m area by 2.2 m depth cores of soil, comprise the Texas A&M; Research and Extension Center - Uvalde lysimeter facility. Two lysimeters, weighing around 15,000 kg, have been placed beneath a linear LEPA irrigation system and used in field production. A third lysimeter measures reference ET values (ETo) and is located in a grassed area near the field lysimeters irrigated by subsurface drip irrigation system. Corn followed by spinach was grown in one of the two crop lysimeters while an onion crop was grown in the second lysimeter. Daily water use was measured on a 5-minute interval. Preliminary results show the possibility of saving approximately 61 to 74 million m3 of water per year in the irrigated farms of the Edwards aquifer region if the newly developed crop coefficients are implemented in conjunction with proper irrigation management techniques. Crop water requirements and Kc determination will be discussed.