TheImprovement ofTropical and Subtropical Rangelands

OVERVIEW 5
results, they must be supplemented by measures that bring immediate
benefits. For example, if a protected area or watershed forest is
threatened by wood-cutting for fuel, it will be necessary to provide
an alternative source of fuel that can be used immediately.
AN IGNORED RESOURCE
Dry grazing lands are largely ignored by governments and technical
assistance agencies. Very little agricultural research funding
goes to rangeland development. This stems partly from the limited
political power of pastoralists or typical rangeland populations, and
partly from the high cost of traditional land rehabilitation practices.
AB a consequence of this neglect, opportunities have been lost
to make vast marginal areas more productive for pastoral people
and other rural populations. Further, deteriorating rangelands contribute
to flooding; when precipitation interception and infiltration
are reduced, runoff correspondingly increases. The problem is compounded
by the downstream effects of flooding, variously including
damage to crope and settlements. Insufficient reeearch is aimed at
finding ways to protect existing rangeland or identifying appropriate
new crope that would complement livestock production. Agronomists
the world over are taught the principles of agricultural land management,
but are unfamiliar with special rangeland techniques. The
uninformed conversion of rangeland to cropland has helped destroy
rangelands. For example, the moldboard plow destroys the surface
vegetation and exposes thin, dry soil to erosion by wind and water.
Clearly, abuse ofrangelands has accelerated erosion, at times rapidly,
at times slowly. AB soil erodes, sediments enter water courses and
river bottoms, estuaries, and deltas, which have become the sink for
nutrient-laden sediments.
CAUSES 01 ENVm.ONMENTAL DEGRADATION
The causes ofland degradation must be understood in developing
a strategy for land rehabilitation. Before costly methods are applied
to promote range improvement, existing degradation forces should be
identified and countered. Although the role of specific social forces
is frequently unclear, devegetation-the progressive disappearance
of plants from the land-is generally the result of human activities:
overexploitation by man and his animals.
Degradation can begin with the depauperization of woodlands