TheImprovement ofTropical and Subtropical Rangelands

REHABILITATION TEOHNIQUES 159
satisfactory procedures have been developed. Sites with the highest
potential should be chosenj otherwise adverse site conditions may
increase the risk of failure.
3. Can proven methods be used?
On many sites, the procedures are known for the general type
of processes but cannot be followed because excessive rocks, steep
slopes, or other factors prevent the use of appropriate equipment or
the application of established methods.
4. Can the area be given proper gruing management after seeding?
Seeding should not be started until proper grazing management
can be assured.
Preliminary Considerations
Plant Cover The usual goal of developing a useful stand of
desirable plants may be achieved by selective plant control or a
change in grazing management. Seeding is an expensive and risky
undertaking, and should be avoided if possible. ~ a general rule, at
least one shrub and 10 desirable herbaceous plants per 9 m 2 should
be present following revegetation.
Terrain and Soil Deep, fertile soils on level to gently sloping
land are preferred sites for seeding. Shallow or rocky soils seldom
have the potential tojustify expensive reclamation measures. Insome
areas, excessive amounts ofsoluble salts in the soil require additional
attention to ensure adequate plant establishment.
Precipitation In addition to being appropriate for the terrain
and soils of the area to be seeded, the species selected should be well
adapted to the precipitation regime ofthe area. Existing vegetation is
generally a good indicator ofavailable moisture. In &reas ofunreliable
precipitation, the germination, establishment, and survival of the
seeded species is better allured ifavailable precipitation is augmented
by additional water made available through precipitation harvesting
~ques.
Competition Meet plants used for revegetation are perennials.
Seedlings of these species are often slow-growing and compete poorly
at the seedling stage with existing, unwanted plants. A good seedbed
will provide the best poaible moisture conditions for germination and
plant growth (figure 7-6). This requires the control of meet existing
plants before seeding.