Abstract

A qualitative land suitability classification of wetlands of southeastern Nigeria, for azolla, a bio-N fertilizer was carried out. The results showed that soils associations represented by Itu Bridge, Oron, Atani, Igbo Beach and Umumbo-Adani are moderately suitable (S2) because of poor drainage, pH (H₂O) of 4.88 - 5.8 and >0.2 cmol (+) kg^-1 K. However, Atani, Igbo Beach and Umumbo-Adani soil associations require the application of phosphorus (P) fertilizers to boost their potentialities. Bonny-Brass and Opobo-Degema soil associations are marginally suitable (S3). They are prone to tidal waves, intermittent stratification and have pH of 4 - 4.6. Obiokpo-Orsu soil association is unsuitable (N) because of its sandiness, excessive drainage and deficiency in nitrogen (N) and potassium (K). It is concluded that biofertilization of wetlands of southeastern Nigeria with azolla is currently not feasible in Obiokpo-Orsu soil association.

Key words:  Land evaluation, azolla, wetland, Southeastern Nigeria.