BIOMASS PRODUCTION AND TRANSPIRATION EFFICIENCIES OF EUCALYPTS IN THE NEGEV DESERT

The above-ground productivity and summer water-use patterns of five species of Western- and central-Australian eucalypts were examined in irrigated plantations in the northern Negev Desert of Israel. Biomass production was evaluated by whole-tree harvesting. Leaf transpiration rates were measured using a steady-state porometer. Eucalyptus salubris was considered the most efficient in its water use because it had the highest productivity (1169 kg ha-1 year-1) and the lowest transpiration rates. Eucalyptus torquata was only slightly less efficient than E. salubris. Eucalyptus woodwardii was comparable in terms of productivity but it transpired at much higher rates. Eucalyptus socialis and E. grossa were the least efficient in their water use because of their significantly lower productivity (<660 kg ha-1 year-1. Of these five species, E. salubris and E. torquata appear to have the most potential for afforestation under conditions comparable to the northern Negev, where the potential evaporation rate is 2140 mm year-1, the soil is a calcareous loam, the mean annual rainfall is about 100 mm, and trickle irrigation provides a supplement of 150 mm year-1. © 1990.