Agronomy and forage quality of Albizia lebbek in the semi-arid tropics.
The tree legume, A. lebbek, although known elsewhere as a useful forage tree and planted for shade in Queensland, has never been grown for feed in N. Australia. Measurements from trees in the Townsville area showed that mature trees in open woodland could make substantial edible DM available without cutting or browsing through the natural seasonal fall of leaves (approx. 60 kg/tree), flowers (30 kg/tree), and pods (30 kg/tree). The existence of a significant feed resource in the fallen inflorescence was unexpected and previously unreported. In addition the tree canopy had a positive effect on grass DM production. The tree products were each fed as the sole diet to sheep for determination of DM intake, DM digestibility, and N digestibility. Green leaf was markedly more digestible (64%) in Nov., shortly after leaf change, than in May (49%). Fallen leaf (9.5% protein) collected from the seasonal leaf change was readily eaten by sheep (1130 g/day) although digestibility was rather low (44%). The fallen flowers were also readily eaten (23% protein; intake 958 g/d; digestibility 57%). Pods were a rich protein source (19%) and were available over a longer period than leaves or flowers.