TheImprovement ofTropical and Subtropical Rangelands
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TheImprovement ofTropical and Subtropical Rangelands

TheImprovement ofTropical and Subtropical Rangelands TheImprovement ofTropical and Subtropical Rangelands

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132 IMPROVEMENT OF TROPIOAL AND SUBTROPIOAL RANGELANDS FIGURE 6-10 Water, 10 esHntial for livestock production, is a ~ource that often p~entl design and manapment problems IUch that rangeland degradation is the ~uh. (J. O'Rourke) [ 1.)ltIZ ,d byCoogIe

GRAZING MANAGEMENT 133 The success of year-long continuous grazing in perennial plant communities is further enhanced because grazing is light during the growing season, and lighter stocking per unit area means leIS soil compaction by livestock when the soil is wet. Some of these same reasons could also be attributed to rotational schemes. Under rotation systeIl18 of grazing on perennial rangelands, units have sustained increased numbers of livestock and have shown greater improvements in range condition than have units grazed continuously on a year-long basis at various stocking rates. An advantage of deferred rotation is the infrequency of livestock movement required. Under the system, livestock must adjust to the new forage of each grazing unit only once every grazing season. A rotation system using as many as 16 units, each grazed 2 weeks or less by 1 or 2 herds, has been studied in South Africa and Zimbabwe. Livestock are not moved at any set time, nor are the units necessarily stocked in sequence. When plants are growing rapidly, the livestock are moved frequently, perhaps as often as every 5 days, to prevent injury to plants. When the plants are dormant, livestock movement is determined by the nutritional requirements of the animals. An evaluation of grazing systeIl18 in southem Africa concluded that the following principles are important: • Slow rotation systeIl18 do not eliminate selective grazing. • In a 16-unit, high-intensity, low-frequency system, 12 units are grued once for about a 2-week period every 6 months, and the 4 other units can be used as reBerve grazing in dry years or given a full year's rest in years of average precipitation. • High-intensity, low-frequency grazing is designed primarily to combine sufficient reet with efficient use to permit rapid restoration of denuded rangelands. There is less advantage to using this system on rangelands in good condition. • Range restoration may be retarded and greater abuse may occur if stocking increases more rapidly than indicated by herbage production. • With variable precipitation, no system can eliminate Belective gruing if Bet gruing periods and stocking rates are maintained, but high-intensity, low-frequency grazing reduces selective grazing. • High-intensity, low-frequency grazing, becauBe it is an intensive system, may require more labor, fencing, and water development, [ 1.)ltIZ ,d byCoogIe

132 IMPROVEMENT OF TROPIOAL AND SUBTROPIOAL RANGELANDS<br />

FIGURE 6-10 Water, 10 esHntial for livestock production, is a ~ource that<br />

often p~entl design <strong>and</strong> manapment problems IUch that rangel<strong>and</strong> degradation<br />

is the ~uh. (J. O'Rourke)<br />

[ 1.)ltIZ ,d byCoogIe

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