Functional Effect of Wood Ash on Soil Quality

The functional effect of wood ash (WA) on soil was investigated to ascertain the effect on soil quality. Soil samples treated with 5% and 10% WA were set-up against the untreated control and analyzed to evaluate the status of their physicochemical parameters, heavy metals, microbiological, and enzyme activity. The analyses were carried out immediately after the treatment and after the soil mineralization. The results observed revealed a shift in the pH of the treated soil samples against the control, before and after mineralization. Electrical conductivity (EC) ranged from 220.48±0.14 to 240.82±0.14 µs/cm before mineralization and 194.40±7.07 to 229.20±14.14 µs/cm after mineralization. The soil samples treated with 5% and 10 % WA had significantly (p<0.05) increased EC when compared to the control before and in the soil treated with 10% WA after mineralization but EC decreased significantly (p<0.05) in the soil treated with 5 % WA after mineralization. The %Nitrogen reduced significantly (p<0.05) in the treated soil samples when compared to the control both before and after mineralization. The soil sample treated with 10% WA had significantly (p<0.05) reduced copper before and after mineralization unlike the soil sample treated with 5% WA which had significantly (p<0.05) reduced copper before mineralization and significantly (p<0.05) increased after mineralization. The soil samples treated with WA had profound microbial load reduction when compared to the control. Before and after mineralization, soil alkaline phosphatase reduced significantly (p<0.05) in the treated samples against the control while acid phosphatase increased significantly (p<0.05) in the treated soil samples when compared to the control. These observations could be linked to the presence of WA in the treated soil samples before and after mineralization. In conclusion, WA treatment increased electrical conductivity, reduced copper and nitrogen concentrations, reduced microbial load and increased some enzyme activities.