Effects of irrigation frequency on germination and on root and shoot yields of Acacia species

Maximum germination response and root + shoot yields of Acacias were obtained at daily irrigation. Any deviation from daily irrigation resulted in variations of performance (germination and growth yield) between the six Acacia species studied. Species of relatively dry habits e.g. A. nubica and A. seyal were more sensitive to water supply compared with those of relatively wet habitats e.g. A. nilotica and A. albida. This was reflected at the establishment phase by the greater production of root + shoot yields of species of drier zones than by those of wetter ones. It is concluded that variations in water supply may account for species adaptation and distribution in semi-arid zones.