Shade Tolerance Of Some Tree Legumes

The shade tolerance of some commonly used tree legume species was compared in a glasshouse experiment at the University of Queensland in 1988. The treatments were 100, 70, 50, 30, and 20% of photosynthetically active radiation effected using shade cloth in a glasshouse. Shade tolerance was assessed by comparing yield at low light levels with that obtained at high light. Using this criteria, shade tolerance was assessed in the descending order Gliricidia sepium > Calliandra calothyrsus > Leucaena leucocephala > Sesbania grandiflora > Acacia villosa > Albizia chinensis. PRODUCTIVE high quality forage species, adapted to shade environments, are required to improve the animal production of ruminants integrated into plantations crops. Most species that have been used for this purpose are herbaceous (Gutteridge and Whiteman 1978, Shelton et al. 1987). Shade-adapted legumes, in particular, are sought for inclusion in pastures because of their superior quality and their ability to contribute biologically fixed nitrogen to the plantation crop. Several studies have reported the shade tolerance of herbaceous legume genotypes which may be suitable for use in plantation environments (Eriksen and Whitney 1982, Wong et al. 1985). However, very little attention has been directed to understanding the shade response of tree legumes, which may also be planted under perennial tree crops to provide additional shade or fodder for ruminants. One exception is the study of Egara and Jones (1977), who showed Leucaena leucocephala to have limited shade tolerance. This study was initiated to provide information on the comparative response to shade of some commonly used fodder tree legumes.