Grass composition and rangeland condition of the major grazing areas in the mid Rift Valley, Ethiopia
AbstractA range inventory and condition study was conducted in three altitude zones: lowland (1 500–1 700m), medium altitude (1 700–2 000m), and highland (2 000–2 500m). Each altitude zone was stratified into four or five important grazing areas. One area represented lightly grazed government ranches or parks which were used as benchmarks, another area represented the seasonal grazing areas with an intermediate grazing pressure and the remaining were the heavily grazed roadsides, lakeshores and other communal grazing lands. The range condition assessment was based on the composition of the herbaceous layer, basal cover, litter cover, relative number of seedlings, age distribution of grasses, soil erosion and soil compaction. Dry matter was sampled in the mid-wet season to assess the relationship between available dry matter and range condition. A total of 36 grass species, 3 legume species, 2 sedge species, 15 other herbs and 31 species of trees were identified. The palatable Cenchrus ciliaris was dominant in the benchmarks and seasonally grazed areas of the lowland while Hyparrhenia spp. dominated in the same areas of the medium altitude. Cynodon dactylon, and the non-palatable Eleusine floccifolia and Pennisetum schimperi were dominant on heavily grazed areas of the lowland, medium altitude and highland, respectively. The total score for range condition of the benchmarks (34 out of 50 points), was significantly higher than that of the seasonally grazed areas (26), the heavily grazed communal grazing areas (19), roadsides (16) and lakeshores (17) (P<0.05). The highlands showed a higher score for benchmarks and seasonally grazed areas only. There was a significant linear relationship between available dry matter of grasses and range condition (excluding unpalatable pioneer grasses, r2 = 0.56, P<0.01). Seasonally grazed areas were identified as key sites for pasture improvement since these are privately owned and managed. Pasture improvement will reduce the grazing pressure on the heavily grazed roadsides, lakeshores and other communally grazed areas.
Keywords: basal cover, above-ground available phytomass, herbaceous species, soil erosion
African Journal of Range & Forage Science 2002, 19(3): 161-166