Biomass yield, botanical fractions and quality of tagasaste, (Chamaecytisus palmensis) as affected by harvesting interval in the highlands of Ethiopia

Tagasaste, a hardy leguminous shrub has potential for wide utilization in the highlands of East Africa. Establishment and productivity of tagasaste at two, three, four, and six months harvesting intervals were evaluated from the first to the forth years of age (1991/1992-1994/1995) in the highlands of Ethiopia. Biomass yield, botanical fractions (Leaf, Edible branch and stem) and quality were assessed. Annual biomass production was substantially greater for six months interval than for the more frequent harvests in a range of 4.7 to 10.2 t ha(-1). Average biomass yield also increased as the plant got older. Leaf proportion of the biomass yield consistently decreased from 71.7 to 45.3% and the stem increased from 0.4 to 25.5% as the harvesting interval was prolonged from two to six months, respectively. However, the longest harvesting intervals were still the most productive of leaf DM from the increased biomass yield. The average crude protein (CP) content and in vitro dry organic matter digestibility (DOMD) of leaf were not significantly affected by harvesting interval. They ranged from 18.0-21.2% and 65.3-70.5%, respectively. Allowing tagasaste to grow during the wet season for four to six months and harvesting during the early dry season could improve the yield of high quality herbage, fuel wood and increase persistence in the highlands of Ethiopia. Tagasaste could be the best browse tree for the highlands of East Africa. It could alleviate problems of feed shortage, soil degradation, low soil fertility through mulching and nitrogen fixing ability, and fuel wood scarcity which are predominantly prevalent in these areas.