Germination and seedling growth of Acacia Senegal (l.) Willd and Parkia Biglobosa (jacq.) as influenced by salinity in Sokoto State Nigeria

An investigation was carried out on the seed germination and seedling growth response of two indigenous savanna tree species (Acacia senegal and Parkia biglobosa) to salt (NaCl). Soil samples from two plots within Dabagi research farm of Usmanu Danfodiyo University Sokoto were used. These samples were taken from Dabagi Upland 2 (DUP2) and Dabagi Lowland (DLL) at the depth of 0-30cm. The seeds were sown in the soil samples of 0.0dSm-1, 2.2dSm-1and 2.8dSm-1 salt levels and observed until complete germination, and growth parameters (height and collar diameter) were measured fortnightly for 12 weeks. It was observed that salinity influenced the germination of seeds of the species with A. senegal (54%) showing a better germination at 2.2dSm-1 compared with P. biglobosa (44%). Secondly, the tree seedlings showed significant differences in their growth over the period of the study. It was observed that on the whole when compared, P. biglobosa showed a significant difference at (P<0.05) between 0.0dSm-1 and 2.8dSm-1. The result indicated that P. biglobosa though a savanna species, does not thrive well in high saline soils and should not be used in agro-forestry plot deep in the savanna where irrigation water may tend to increase soil salinity.