Bulk Density (Bd) (g/cm3)
The
soil bulk density ranged from 1.48 g/cm3 to 1.73 g/cm3. Sand and loam normally
indicate bulk density variation of 1.2 and 1.8gcm3, respectively as reported by
(Unger and Kasper, 1994). Considering the values obtained, it showed that the
soil can really support plant growth.
However,
results also showed that the contamination of engine oil and palm oil waste had
not negatively affected the soil bulk density. Therefore, the soil had the
ability to function for support, water, solute movement and soil erosion.
Total Porosity (TP) (%)
Statistical
results showed a variation in total porosity between treatments was significant
at 5% probability level...
Read Also: Effect of soil contaminated with different waste oil on the soil chemical properties.
Read Also: Effect of soil contaminated with different waste oil on the soil chemical properties.
However,
palm oil waste treated soil had the highest porosity level (44%), followed by
the mixture of engine oil and palm oil waste sample with the value of 41%.
The
engine oil contaminated soil had the least porosity level of 35%. The increase
in porosity level were in the order of T2 > T3 > T1.
Gravitational Moisture Content (GMC) (%)
Results
showed that there was a statistically significant change in gravitational
moisture content of the soils at 5% level when the studied samples were
compared with the control.
The
soil moisture values were 10% (control), 8% (engine oil, T1), 16% (palm oil
waste, T2) and 13% (mixture, T3). These implied that engine oil contaminated
had low moisture content compared to control and other samples.
However,
palm oil waste contaminated soil sample had the highest moisture content
compared to the control. The increase in gravitational moisture contents of the
samples was in the order of T2 > T3
> T1 (Table 3).
The
low moisture content of engine oil contaminated soil could be attributed to the
presence of hydrocarbons and polycyclic aromatic hydrocarbons which can cause
an increase in soil hydrophobicity, resulting to a decrease in the moisture
holding capacity of the soil and this was supported by the findings of Balks et
al., (2002).
Effects of Hydrocarbons Contaminants on Soil
Productivity
Maize
grain yield was low in engine oil treated soil and mixture of engine oil and
palm oil waste treated the soil with the yields of 1.89kg/ha and 2.01kg/ha,
respectively compared to control with the yield of 2.56kg/ha.
This
implied that the engine oil treated soil impacted negatively on soil
productivity because yield would be reduced due to the poor fertility of the
soil and growth performance of crops. However, palm oil waste contaminated soil
led to grain yields of 3.45kg/ha.
The
yield level in the palm oil waste treated soil implied that palm oil
waste/effluent could be used as a supplement for inorganic fertilizer in the
soil. These were supported by the findings of Ojeniyi, et al., (2010) Adekayode
and Olojugba, (2010) and Mbah et al., (2010) whose works reported an increase
in soil nutrient content and uptake of nutrients by maize during decomposition
of palm oil effluents and other waste from palm oil production.
There
was a significant improvement in the maize plant height and leaf length at 5%
probability level. Engine oil contaminated soil had stunted growth as
manifested in the maize plant height of 50cm and leave a length of 65cm
compared to control with 69cm and 78cm height and leaf length respectively.
However,
the palm oil waste treated soil recorded the highest maize plant height and
leave a length of 77cm and 82cm, respectively. The increase recorded would be
attributed to the release of nutrient to the soil by palm oil waste during
decomposition.
This is in consonance with the findings of Anike, (2000) who reported that palm oil effluent/waste during decomposition releases nutrients required by crop plant for growth and productivity
Tags
Agriculture