362 THE FUTURE OF ARID LANDS 
tion of economic returns resulting from fertilization of unimproved 
ranges. 
What Are the Possibilities of Maintaining Larger Human Popula- 
tions in Arid Areas? 
The answer to this question seems to follow directly from the 
preceding discussion. It has been shown that arid lands in a 
Mediterranean type climate can be made from two to ten times 
more productive by improved agricultural practices. This makes 
the livestock economy a more efficient one, and if one acre can 
be made to produce what now takes two to ten acres, a larger 
human population can be supported. 
It was pointed out, above, that one of the difficult problems 
confronting the range manager is efficient harvesting of the forage 
crop. Because animals are “selective’’ in their grazing habits, that 
is, when they have a choice they will first graze the most palatable 
plants. On a so-called overgrazed range, reducing livestock 
numbers for the season 1s of little avail since the animals can still 
select the most palatable plants first. Such a policy will result only 
in continuing the trend of range depletion. 
A three-field, three-year rotation grazing plan for California 
foothill ranges has been described earlier in this paper. 
The California Forest and Range Experiment Station con- 
ducted five years of research on a five-field, five-year rotation 
grazing plan at their Burgess Spring Experimental Range on the 
Lassen National Forest in Northeastern California (A. L. Hor- 
may, unpublished). This is in the Great Basin zone where the 
grazing season is June 1 to September 30. 
The California Region, V, of the U. S. Forest Service has put 
this plan into operation on a 32,352-acre allotment, of which 20, 
645 acres are usable as range. The allotment is fenced into five 
fields of approximately equal carrying capacity. During the §-year 
period each of the range units receives a different grazing treat- 
ment. The timing of heavy grazing and resting is based on the 
growth requirements of Festuca idahoensis (Idaho fescue)—the 
key species in this allotment. This plan has been put into effect 
with no reduction in livestock numbers, and it is confidently 
expected that grazing capacity will be increased in later years. 
