Effects of amendments and bioaugumentation of soil polluted with crude oil, automotive gasoline oil, and spent engine oil on the growth of cowpea (Vigna ungiculata L. Walp)

Abstract

The effects of sawdust and waste cotton as soil amendment and bioaugumentation withPleurotus pulmonarius (pp) on soil polluted with crude oil (COIL), automotive gasoline oil (AGO), and spent engine oil (SEO) on the growth of cowpea (Vigna ungiculata L. Walp) was investigated. There was a significant improvement (P = 0.05) on the growth of cowpea when polluted soil was amended and bioaugmented with P. pulmonarius (pp) after one month of incubation when compared with the result of planting on polluted soil with no amendments and bioaugumentation. Addition of waste cotton as an amendment and P. pulmonarius as bioaugumentation agents to crude oil polluted soil significantly reduced time of seed germination from 8 to 3 days, increased seed germination from 60 to 96%, plant height from 10.3 to 22 cm, leaf number from 3 to 5 and biomass from 0.5 to1.5 g dry wt. Similar reductions in time of germination, increases in percentage germination, plant height, leaf number and total biomass in cowpea plants grown in automotive gasoline oil and spent engine oil polluted soils, amended with waste cotton or saw dust and bioaugumented with P. pulmonarius were observed in this study. Key words: Amendments, bioaugumentation, Pleurotus pulmonarius, Vigna and growth.