Edwin-Wosu N. L.
A comparative ecological study was conducted to ascertain the degree of utilization and restoration of nutrient element of crude oil polluted soil by two agro-forestry species (Luecaena leucocephala Lam. De wit. [Lead tree] and Bauhinia monandra Kurz). The study carried out in three phases involves the use of classical analytical methods of Nelson and Somners, Bray No. 1, Micro-Kjeldahl Stewarte methods and SAS statistical package. Result generally show that nitrogen and phosphorus were depleted in the post-pollution, though with the former significantly (p<0.05) lower than pre-pollution phase. The organic carbon and matter content had a significant (p<0.05) increase in post-pollution than pre-pollution. In phytoapplication process between the species treated soils L. leucocephala soil recorded significant (p<0.05) increase in nitrogen and concomitant increase in species content. Bauhinia monandra soil had non-significant (p<0.05) increase and decrease in species content than L. leucocephala soil and species respectively for phosphorus content. Carbon and organic matter content recorded reduction between soil and species content with significant (p<0.05) difference in L. leucocephala treatment. The trajectories in nitrogen, carbon, organic matter and phosphorus in L. leucocephala treated soil are indicative of their utilization in bioremediation process by L. leucocephala plant. It also shows its enhancing potential in environmental management. The unexpected ineffectivity of B. monandra is attributed to its peculiar non-symbiotic characteristics and the inadequacy of nodulation and low utilization of the nutrient for bioremediation. Based on this L. leucocephala has proved more suitable for bioremediation practice in a polluted terrestrial habitat.
