Field performance of tagasaste (<i>Chamaecytisus Palmensis</i>) under different harvesting management in a tropical highland area of Ethiopia

Abstract

Tagasaste (Chamaecytisus palmensis) is one of productive multipurpose tree species grown in the tropical highlands of Ethiopia. Despite its potential role as a source of forage and natural resource conservation, adequate studies were not made on agronomic practices such as establishment, harvesting managements and utilization. The objectives of this study were to investigate the effect of establishment and subsequent harvesting managements on biomass (BM) yield, crude protein (CP) content, botanical fractions of total biomass and persistency of tagasaste. Establishment of tagasaste was undertaken for three consecutive years at Holeta Research Center (HRC) in the highlands of Ethiopia. The two harvesting management trials, harvesting stage and growing season were arranged separately in a randomized complete block design with three replications. In harvesting stage study, four treatments of harvesting stage including HS1 (3 harvests per year at 4 months interval), HS2 (2 harvests per year at 6 months interval), HS3 (one harvest at 8 months and the 2nd harvest after 4 months) and HS4 (one harvest at 10 months and the 2nd harvest after 2 months) were compared annually. In the growing season study, tagasaste was allowed to regrow for 6 months so that exposed to the main rain, dry and short rainy seasons of the area. Planting and harvesting year had a significant (P<0.01) effect on BM yield during establishment and subsequent years. Mean annual dry BM yield was 7.3, 9.5 and 11.3 t ha-1, out of which about 55% was edible forage during the establishment, second and third year, respectively. Tagasaste produced 7.7, 11.8, 9.9 and 12.2 t ha-1 dry BM and 0.72, 0.97, 0.83 and 1.12 t ha-1 CP from edible forage when harvested at HS1, HS2, HS3 and HS4, respectively. Tagasaste regrowth during the main rainy season, dry season and short rainy season produced 6.7, 1.7 and 5.8 t ha-1 dry BM per 6 months, respectively. From this study it is concluded that harvesting management could substantially improve performance and annual yield of tagasaste. Harvesting either at HS2 or HS4 improved BM, edible forage and CP yields of tagasaste. Therefore, these agronomic management practices has vital role to increase the productivity of tagasate in the central highlands of Ethiopia.

Keywords: tagasaste, harvesting management, season, biomass, crude protein, tropical highlands