Laboratory investigations were conducted to determine effects of liming materials and inorganic phosphatic fertilisers on some indices of soil fertility. Results showed that soil bulk density decreased with increasing additions of liming materials and that interaction effects of dolomitic limestone and mineral fertiliser P increased soil pH from 4.4 for the unlimed top-soils to 6.3 after 3 t ha‒1 of dolomitic limestone and 300 kg ha‒1 Super D (a compound fertiliser) were added. Inverse statistically significant relationships were observed between exchangeable Al and lime (P £ 0.01); exchangeable Al and pH (P £ 0.01); and exchangeable Al and extractable P (P £ 0.01). About 98% of the total variation in exchangeable Al was accounted for by the applied dolomitic limestone. The present investigations have demonstrated that the observed low fertility of the acidic soils may be attributed to its association with low P availability; reduced nutrients such as K, Mg and Ca; and adverse effects of exchangeable aluminium.
Key words: Liming effects, exchangeable aluminium, indices of soil fertility.