Estimation of Reference Crop Evapotranspiration for the Life Zones of Saudi Arabia.

Reference crop evapotranspiration (ETo) was estimated by FAO-modified Penman, Blaney-Criddle, Jensen-Haise and Hargreaves methods for the 14 life zones of Saudi Arabia. Linear regression relationships between (ETo) values estimated by the Jensen-Haise and other methods are presented. Comparison between ETr and actual evapotranspiration of lucerne grown at Hofuf indicated that the Jensen-Haise method is the most suited for prediction of ETo values in the subtropical per arid desert zone. Mean monthly ETr values estimated by the Penman method were recommended for two life zones, whereas those by Jensen-Haise method were recommended for the remaining 12