338 THE FUTURE OF ARID LANDS 
interpretation of air photos was found to be of great value to the 
program. 
2. Study of the human factor in relation to land use and land 
tenure as well as to livestock numbers in all phases of the program. 
Unless the recommended practices are acceptable to the people 
and in harmony with their customs and way of life, the whole 
program of improvement is bound to fail. The extensive damage 
that has been done in most of the desert and semi-desert areas 
resulted from factors beyond the control of the people who are 
always held to blame. The instability of life and lack of property 
rights are the real causes of over-grazing and nomadism. Nomadic 
life is a forced way of living and will be dropped when a good 
alternative is available. 
2. Species adaptability tests, including methods of establishing 
plant species by reseeding and their response to grazing, is ihe 
means of pointing the way for large-scale reseeding. We have 
tested almost 300 species of native and introduced plants. Only a 
few proved to be of some use such as Phalaris tuberosa, Ehrharta 
calycina, Agropyron desertorum, Medicago sativa, Melilotus species, 
Sanguisorba minor, Atriplex species, Kochia indica and Prosopis 
juliflora. Many natives hold much promise once seed supply is 
developed; the following are examples: Dactylis glomerata var. 
hispanica, Stipa lagascae, Oryzopsis miliaceae, Cynodon dactylon, 
Potertum varicosum, Plantago albicans, Moricandta nitens, Poly- 
gonum spp., and Lotus creticus. 
It is worth while to mention that it was comparatively easier at 
the beginning to obtain foreign seed and information from already 
established stations abroad than to collect our own. 
From observations of how many species failed to establish 
themselves against how much less succeeded, one may very soon 
observe and recognize the better adaptation of the native species. 
Selection of sites needs careful study. In our case, one screening 
nursery and twelve outplanting plots have been established along 
a 300-mile strip of land. 
4. Study of soil and water conservation methods and applica- 
tion of certain practices, including water spreading systems. 
5. Natural recovery through protection and management. 
