ASCE will be sunsetting the Civil Engineering Database (CEDB) in the coming months. We encourage you to start using the ASCE Library to perform content searches. In the ASCE Library, you can save your search results as well as receive email content alerts when new content relevant to your area of interest is published. Try it out today at https://ascelibrary.org.

 

Growing Season Evapotranspiration and Crop Coefficient

by Esmaiel Malek,
Gail E. Bingham,



Document Type: Proceeding Paper

Part of: Management of Irrigation and Drainage Systems: Integrated Perspectives

Abstract:

The Bowen ratio-energy balance (BREB) method was used to continuously estimate 20-minute actual evapotranspiration (ET_a) in the middle of a 36-ha well-watered alfalfa field from 10 April to 5 October, 1992. Daily totals of ET_a were compared with potential evapotranspiration (ET_p) estimated using the modified Penman method. About 90% net radiation (R_n) was utilized for ET_a, and the crop coefficient K_c = ET_a/ET_p was 79%. The crop coefficient occasionally was greater than unity. Regression analysis revealed that R_n = 0.560R_s - 1.317 with r = 0.933 and R_n = 0.556R_s - 0.830 with r = 0.959 for clear and clear-plus-cloudy sky conditions, respectively, during the season where solar radiation (R_s) and R_n are in MJ m^-2. This BREB method is a promising tool for automated irrigation systems in remote areas.

Subject Headings: Evapotranspiration | Crops | Solar radiation | Regression analysis | Irrigation systems | Vegetation | Seasonal variations

Services: Buy this book/Buy this article

 

Return to search