BETTER ADAPTATION OF PLANTS 359 
Annual legumes are perhaps the most promising species for im- 
proving and increasing returns per acre in arid areas. They are 
more nutritious than annual grasses, whether green or mature, and 
they provide more flexibility to the year-long livestock operation. 
In some instances seed can even be broadcast into resident sod 
without seedbed preparation (69). 
Seeding of long-lived species. Begin tests on arable land, if at 
all possible, and use the best agronomic methods to establish a 
stand (42, 43). We have found that a summer crop such as sudan- 
erass (Sorghum vulgare var. sudanenstis) 1s ideal preparation for a 
dryland pasture seeding. The sudan provides some summer feed, 
and the grass and legume seeds can be planted directly into sudan 
stubble without further seedbed preparation. Actual seedling 
counts at the University of California’s Hopland Field Station 
indicated that 19 times as many seedlings of Phalaris tuberosa var. 
stenoptera were established following sudan as following wheat. 
This is primarily due to the reduction in competition of resident 
species by the sudan crop. 
Adapted perennial grasses are worth striving for since they 
have a much longer season of use than annual forage (33, 34, 38, 
40, $1). Again, fertilization together with judicious grazing in- 
creases yields of perennials. In an experiment at the University 
of California’s Hopland Range Field Station 400 pounds per 
acre of ammonium-phosphate-sulfate fertilizer increased peren- 
nial forage production four times over the 200 pounds per acre 
application. Fertilization the second year after seeding yielded 
two-tenths pound per day of sheep weight gains compared with 
one-tenth pound unimproved, unfertilized range at the Station. 
Fertilization, combined with controlled grazing, not only 
increases forage production but may also improve its quality by 
creating a more favorable environment for the desirable species. 
Many of the species on lands of low fertility are “invaders” 
which by their very nature are the least desirable plants from the 
standpoint of livestock production. They may be highly desirable 
from the standpoint of soil conservation, but man cannot afford 
to wait for the successional trends that over the centuries will 
result in an improved cover. 
A rotational system of grazing should be designed to harvest 
