In the early seventies, scientists in Israel and The Netherlands started a cooperative project on actual and potential production under semi-arid conditions. In Israel research concentrated on primary production of natural pastures and small grain crops, and on the associated secondary production of small ruminants. Most of the experimental work was carried out at the Migda Experimental Farm in the semi-desert of the northern Negev where the long- term average annual rainfall is 250 mm. In The Netherlands existing facilities in Wageningen were used for measuring growth, photosynthesis and...