Cohen, Y., Dept. of Environ. Phys. and Irrigat., Agricultural Research Organization, Volcani Center, P.O.B. 6, Bet Dagan 50250, Israel, Institute of Soils and Water, P.O.Box 6, Bet Dagan 50250, Israel
Adar, E., Jacob Blaustein Inst. Desert Res., Department of Geology and Mineralogy, Ben-Gurion University of the Negev, Sede Boqer Campus 84990, Israel
Dody, A., Jacob Blaustein Inst. Desert Res., Department of Geology and Mineralogy, Ben-Gurion University of the Negev, Sede Boqer Campus 84990, Israel
Schiller, G., Department of Natural Resources, Agricultural Research Organization, Volcani Center, P.O.B. 6, Bet Dagan 50250, Israel

Expanding the area of tree plantations in the Negev desert of Israel requires prior quantification of the water resources in small watersheds. Combined hydrological and physiological measurements were used to study a 'liman' (floodwater irrigated plot) in the Negev highlands, where Eucalyptus and other tree species are grown successfully. The amount of water flowing into the liman, surplus wilier flowing out of the liman, temporal soil moisture distribution, and water uptake by the trees were determined. Depending on rainfall intensity and distribution during the season, the liman received 2-3 times the total seasonal rainfall. Although the study was conducted during a year with a negligible amount of rainfall, the transpiration rate was closely correlated with potential transpiration throughout the year. The amount of water extracted from the soil was less than the time-integrated transpiration rate from the trees, suggesting that a water source other than soil water storage was available to the trees. We suggest that the trees extracted water from the rock fractures and/or utilized the lateral flows over the rock/soil interface.