TheImprovement ofTropical and Subtropical Rangelands

REHABHJTATION TECHNIQUES 165
FIGURE 7·8
A preu drill. (A,riellltllral Raean:h Service)
in some way if it is to germinate and become established. This can
variously be done by dragging a chain or branches over the seeded
area, raking with a hand implement, or driving a vehicle or livestock
over the area after scattering seed. Seed size and the condition of
the leedbed are important influences on the extent to which seed is
covered with soil. A seedbed that is 5-8 cm of loose soil generally
sloughs sufficiently to cover the seed. Covering the seed with a mulch
is better than no coverage at all, but mulch coverage is inferior to
soil coverage. If mulches are used in conjunction with leeding, best
results are obtained by broadcasting the seed, covering it with soil,
and then applying mulch.
Limitations to broadcast leeding are:
• Large quantities of seed are required (approximately double
the amount used in drill seeding).
• Distribution of seed is often poor.
• Covering of seed is poor compared with drilling.
• Seed loss to birds and rodents can be great.
• Establishment is generally slower.