Revised FAO Procedures for Calculating Evapotranspiration: Irrigation and Drainage Paper No. 56 with Testing in Idaho
Publication: Watershed Management and Operations Management 2000
Abstract
In 1998, the Food and Agriculture Organization of the United Nations (FAO) published FAO Irrigation and Drainage Paper No. 56, a revision of the earlier and widely used Paper No. 24 for calculating evapotranspiration (ET) and crop water requirements. The revision uses a single method, the FAO Penman-Monteith equation, for calculating reference evapotranspiration (ETo). In addition to the "mean" crop coefficient (Kc) values of FAO-24, FAO-56 provides tables of "basal" crop coefficients that represent ET under conditions having a dry soil surface. Associated equations for predicting evaporation from bare soil associated with crop transpiration are based on a water balance of the soil surface layer. Comparisons of daily ET from three agricultural crops are made between lysimeter measured ET and the basal Kc method of FAO-56 and the time-based basal Kc procedure of Wright (1982). Standard errors of estimate and accuracies were similar between the two methods and averaged about 0.77 mm/day or 15%.
Get full access to this article
View all available purchase options and get full access to this chapter.
Information & Authors
Information
Published In
Copyright
© 2000 American Society of Civil Engineering.
History
Published online: Apr 26, 2012
ASCE Technical Topics:
- Agriculture
- Business management
- Crops
- Drainage
- Evaporation
- Evapotranspiration
- Geomechanics
- Geotechnical engineering
- Hydrologic engineering
- Irrigation
- Irrigation engineering
- Irrigation water
- Management methods
- Organizations
- Practice and Profession
- Soil mechanics
- Soil properties
- Soil water
- Water (by type)
- Water and water resources
- Water management
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.