On-farm productivity of <i>Acacia angustissima</i>, <i>Calliandra calothyrsus</i> and <i>Leucaena leucocephala</i> in a subhumid area in Zimbabwe

Abstract

Smallholder dairy farmers in Natural Region II, especially in Chikwaka Communal Area, adopted Acacia angustissima, Calliandra calothyrsus and Leucaena leucocephala in the 1995/96 season as alternatives for supplementing expensive commercial dairy feeds. Although several on-station trials have been done in the subhumid region of Zimbabwe,  there have been no studies assessing on-farm yields of the introduced fodder species. This study evaluated productivity in a communal area under varying soil (pH, nitrogen, phosphorus and potassium) and  management conditions (protection and tree density). Leaf  productivity was high on farms with relatively higher soil P. Leaf yields  ranged from 0.4–3.3 t DM ha^–1 for A. angustissima, 0.8–5.6 t DM ha^–1 for C. calothyrsus and 0.2–0.7 t DM ha^–1 for L. leucocephala Acacia angustissima, Calliandra calothyrsus and Leucaena leucocephala in the 1995/96 season as alternatives for supplementing expensive commercial dairy feeds. Although several on-station trials have been done in the subhumid region of Zimbabwe,  there have been no studies assessing on-farm yields of the introduced fodder species. This study evaluated productivity in a communal area under varying soil (pH, nitrogen, phosphorus and potassium) and  management conditions (protection and tree density). Leaf  productivity was high on farms with relatively higher soil P. Leaf yields  ranged from 0.4–3.3 t DM ha^–1 for A. angustissima, 0.8–5.6 t DM ha^–1  for C. calothyrsus and 0.2–0.7 t DM ha^–1 for L. leucocephala Acacia angustissima, Calliandra calothyrsus  and Leucaena leucocephala in the 1995/96 season as alternatives for supplementing expensive commercial dairy feeds. Although several on-station trials have been done in the subhumid region of Zimbabwe,  there have been no studies assessing on-farm yields of the introduced fodder species. This study evaluated productivity in a communal area under varying soil (pH, nitrogen, phosphorus and potassium) and  management conditions (protection and tree density). Leaf  productivity was high on farms with relatively higher soil P. Leaf yields  ranged from 0.4–3.3 t DM ha^–1 for A. angustissima, 0.8–5.6 t DM ha^–1 for C. calothyrsus and 0.2–0.7 t DM ha^–1 for L. leucocephalawith mean values of 2.2, 2.6 and 0.4 t DM ha^–1, respectively. The low yields  of L. leucocephala were associated with psyllid (Heteropsylla cubana) infestation. Decrease in tree density (low population) resulted in reduced yield. Poor performance was also attributed to uncontrolled browsing. Influence of soil characteristics could not be confirmed, but  there were indications that low soil phosphorus may have adversely affected tree growth. The yields were generally lower than on-station, which implies that there is room for improving fodder tree yields in this subhumid region, through improving the availability of P, planting a high density of trees, and protecting them from uncontrolled browsing.

African Journal of Range & Forage Science 2009, 26(2): 75–80