| Grazing and rangeland development for livestock production |
|Management of rangelands and other grazing lands of the tropics and subtropics for support of livestock production. Technical Series Bulletin No. 23|
|IV. The elements of productive grassland management.|
a. The motive for uncontrolled burning will largely be removed when management practices increase feed supply, and the stocking rate is adjusted to current feed supplies. Providing the necessary mineral supplement also is helpful.
b. Any burning to reduce invasions of the rangeland by woody shrubs and scrub trees, as well as reduction of other useless vegetation, should be done under carefully controlled conditions as noted in section III.7. Controlled burning also is a useful practice in preparation for introduction of promising new grasses and forage legumes.
c. Other methods of reducing the abundance of undesired vegetation may include tractor bulldozing or root plowing, hand grubbing of sparse stands of invading species, and the application of herbicide chemicals by ground applicators or by aerial application. Each of these methods is costly and should be undertaken only under recommendation by qualified specialists, and with close supervision by a qualified expert.
d. Before undertaking costly control methods, it would be prudent to make limited field trials of the proposed practices and materials, to determine their effectiveness as well as costs. It is clear that any costly practices should be limited to land areas having favorable soil conditions for growth of forage grasses and legumes. The benefits to be derived from controlled grazing to limit invasions of useless vegetation may be evaluated at low cost, and more expensive methods should be undertaken only as a supplement to controlled grazing.
e. Browse forage plants. It must not be assumed that palatable nutritious forage consists solely of grasses and herbaceous legumes, particularly in regions of limited rainfall. Browse plants include a wide variety of low-growing species with woody main stems, but which have palatable leaves and finer stem branches. Cattle make little use of such browse, but sheep, goats and camels may subsist quite well on palatable browse alone. There are marked differences between browse species, and the management practices should be designed to foster the better species.
Browse is important in desert ranges for feed production on land areas in runoff channels that are normally dry, but contain waterborne sediments (sand and silt). Where these alluvial sediments have appreciable depth, they act as reservoirs for runoff water, and browse plants make intermittent growth throughout the year, drawing on water stored in these sediments from occasional rains.
It is obvious that useful browse plants should not be regarded as undesirable woody vegetation in situations where grasses and forage legumes are not well adapted. Browse plants are usually native species, but there may be substantial opportunities for introducing superior species from other continents or regions, such as mesquite (Prosopis species) from North America, and reintroducing browse forage species that were once present but have been destroyed by overgrazing.