Present address: Research and Development of the Southern Jordan Valley, Bikat Hayarden Experimental Station, Israel.
Received for publication 27 July 1987. Contribution from the Agricultural Research Organization, Bet Dagan, Israel, no. 2094-E, 1987 series. This work was presented in partial fulfillment of the requirements for the PhD degree by G.N. We thank the Dan Sprinklers Co., A. Israeli, and the Southern Jordan Valley Experimental Station for their techical support. The cost of publishing this paper was defrayed in part by the payment of page charges. Under postal regulations, this paper therefore must be hereby marked advertisement solely to indicate this fact.