Potential of magathyrsus maximum and pennisetum glaucum for sustainable soil restoration

Abstract

The Niger Delta is plagued with cases of soil contamination with crude oil. In order to source for locally available low cost materials to remediate such soils, some plant materials such as Magathyrsus maximum and Pennisetum glaucum were employed to determine their remediation potentials of three soil samples: B1, B2 and B3 with B1 as control, for a period of eighteen weeks. Soil were taken from Highcast demonstration farm, the soil were free from crude oil contamination. 400g of these soils were placed in a plastic container for stimulation. 70g of crude oil was mixed thoroughly with 4000g of loamy soil in plastic containers. This contamination procedure was done in plastic containers. Soil samples were collected with hand trowel and placed in a plastic container for analysis. At the end of the eighteen weeks of investigations, there was an increase in pH values for B2 from 5.750±0.034 to 6.990±0.041 while for B3, it increased to 6.780±0.041. EC values dropped from 427 dS/m to 261 dS/m and 269 dS/m for B2 and B3 respectively, MC values increased from 17.3 ± 0.016% to 26.3 ± 0.057 and 24.9 ± 0.054% for B2 and B3, Samples B2 and B3 exhibited decreases in bulk density, decreasing from 1.386 ± 0.004 g/cm³ to 1.349 ± 0.025 g/cm³ and 1.358 ± 0.082 g/cm³, TNC values for B2 and B3 decreased from 0.131 ± 0.316% to 0.101 ± 0.701% and 0.124 ± 0.105%. The AP values for samples B2 and B3 decreased from 11.610 ± 0.097 mg/kg to 4.000 ± 0.054 mg/kg and 4.420 ± 0.008 mg/kg. The TOC values for samples B2 and B3 decreased from 3.990 ± 0.082% to 1.920 ± 0.035% and 1.940 ± 0.081%. The TOM values for samples B2 and B3 increased from 1.101 ± 0.017% to 1.267 ± 0.048% and 1.195 ± 0.005%, THC values for samples B2 and B3 decreased from 89.280 ± 0.108 mg/kg to 7.900 ± 0.082 mg/kg and 11.780 ± 0.025 mg/kg, respectively. The TPC values for samples B2 and B3 increased from 0.36 ± 0.187 ppm to 0.86 ± 0.057 ppm and 0.79 ± 0.076 ppm, respectively. The results obtained from this investigation show that Magathyrsus maximum and Pennisetum glaucum has the potential for remediating crude oil contaminated soil.