Ecological factors affecting the early development of seedlings of three Acacia species from Ethiopia

Abstract

Three Acacia species from Ethiopia, namely Acacia nubica, A. seyal and A. horrida, were tested for growth and resistance to drought during the establishment phase in glasshouse and laboratory conditions. The experiments showed that each species has different preferences for particular environmental conditions. Temperature, water availability and depth of sowing were the most important factors affecting the growth of these plants. Soil type had a similar effect on all of them, sandy and loamy conditions being preferred to clay. Acacia nubica and A. horrida proved to respond positively to hot environments, although the first species requires a good water supply and the second is capable of growing under water shortages. Acacia seyal seems better adapted to sub-humid climate types. A high resistance to drought conditions was a common characteristic of all three species: survival after 24 days without any water under high evaporation conditions proves that these Acacia species, particularly A. horrida, are well adapted to cope with harsh droughts.