The efficacy of three wild-type legumes in the remediation of agricultural soils contaminated
with 1% (lightly impacted), 3% (moderately impacted), and 5% (heavily impacted) crude-oil was
assessed, using soil physicochemical and biological properties (soil quality indicators) as
evaluation criteria. Results after a 15-month remediation period showed that only Leucaena
leucocephala failed to germinate. The level of MC in the Peltophorum pterocarpum-remediated
soil samples was significantly (p>0.05) elevated to 87%, relative to the respective contaminated
samples, while those of THC (94%), THUB (824%), K+ (53%), Ca2+ (59%) and Mg2+ (58%)
were significantly (p>0.05) reduced; the pH was non-significantly (p<0.05) elevated to 14%,
whereas the Na+ (35%) and THB (5%) were non-significantly (p<0.05) reduced. The Crotalaria
retusa-remediated soils had the level of MC (48%) significantly (p>0.05) elevated, while those
THC (95%), THUB (712%), K+ (58%), Na+ (54%), Ca2+ (77%) and Mg2+ (52%) were
significantly (p>0.05) reduced; the pH was non-significantly (p<0.05) elevated to 12%, whereas
the THB was non-significantly (p<0.05) reduced by 12%. These results indicate that L.
leucocephala ‘may’ not be a good crude-oil remediating leguminous plant, while both P.
pterocarpum and C. retusa are efficient crude-oil remediating leguminous plants.
