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

Abstract

Tagasaste, a hardy leguminous shrub has potential for wide utilizationin the highlands of East Africa. Establishment and productivity oftagasaste at two, three, four, and six months harvesting intervals wereevaluated 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 wereassessed. Annual biomass production was substantially greater for sixmonths interval than for the more frequent harvests in a range of 4.7 to10.2 t ha–1. Average biomass yield also increased as theplant got older. Leaf proportion of the biomass yield consistentlydecreased from 71.7 to 45.3% and the stem increased from 0.4 to25.5% as the harvesting interval was prolonged from two to sixmonths, respectively. However, the longest harvesting intervals were stillthe most productive of leaf DM from the increased biomass yield. Theaverage crude protein (CP) content and in vitro dry organic matter digestibility (DOMD) of leaf were not significantly affected by harvestinginterval. They ranged from 18.0–21.2% and65.3–70.5%, respectively. Allowing tagasaste to grow duringthe wet season for four to six months and harvesting during the early dryseason could improve the yield of high quality herbage, fuel wood andincrease persistence in the highlands of Ethiopia. Tagasaste could be thebest browse tree for the highlands of East Africa. It could alleviateproblems of feed shortage, soil degradation, low soil fertility throughmulching and nitrogen fixing ability, and fuel wood scarcity which arepredominantly prevalent in these areas.