392 THE FUTURE OF ARID LANDS 
up here. Special stress will be laid on the problems. Most of these 
could not be seen at the start, and evolved only during the course 
of the work. Based on the experience gained during this work, it 
will be possible to evaluate more realistically the future possibili- 
ties of desert agriculture and its contribution to the solution of the 
human food problems. 
The first lesson to be learned—important in the past and even 
more so for future work—was that desert agriculture is possible 
only when preceded by planned, thorough, scientific fact finding 
about the area involved. Geological, pedological, biological (es- 
pecially phytogeographical, phytosociological, and plant physio- 
logical), meteorological, and archaeological surveys must be 
carried out. These surveys have to be done cooperatively. Vital 
meteorological data, for example, which could not, in our case, be 
based on decades of records, could be worked out only on the 
evaluation of ecological and phytosociological observations. For 
this purpose the method of “shifts in amplitude,” using the IE- 
amplitude of certain indicator plants (7-11) or the distribution 
and limits of distribution of certain plant associations (g-I1, 42, 
45, 46, 48) are very useful. We may point out here that ecology, 
phytogeography, and phytosociology are very important auxiliary 
disciplines for all surveys in general. Thus, for instance, no pedo- 
logical survey is complete without the donthrien map of the 
main plant associations (42, 48), and the most important demarca- 
tion of the borderlines of arable zones can be done only by ob- 
serving the yearly fluctuations of the annual vegetation (10, 47). 
These surveys should, therefore, never be an ad hoc compilation of 
facts but an integrated product of scientific teamwork, without 
emphasizing only immediate practical needs. 
10. The agricultural settlements of Sde Boker (in the Negev High- 
lands), Mashabei Sade, and Revivim (on the loess plains), Yotvata and 
Fin Yahav (in Nahal Arava). 
Special thanks are due to the Ford Foundation. A great part of the 
work reported here could be carried out only with the help of the generous 
grant given us by the Ford Foundation. By doing so the Ford Foundation 
tes greatly furthered our knowledge of desert agriculture with all the 
practical consequences thereof. 
