Environmental Impact of Bush Burning on the Physico-Chemistry of Mangrove Soil at Eagle Island, Niger Delta, Nigeria

Abstract

Wetland soils derive their chemical composition from the sedimentary rock underneath. Among the metals produced are trace and nutrient elements which facilitate plant growth. Bush burning near mangrove forest is a common practice that has not been given much attention despite its negative impact on the environment. We thus hypothesize that the application of fire on wetland soil will negatively impact the soil chemistry. We collected soil samples from burnt and unburnt soilsat different distances from the point of burning to compare the concentration of nutrient elements (Calcium (Ca2+), iron (Fe), Magnesium (Mg), Nitrate (), Phosphate ( ) and Potassium (K). The result revealed that there was significant difference between metals (P < 0.05). Iron had the highest overall concentration in burnt (10743.75 ± 1508.39 mg/kg) and unburnt (8854.02 ± 1734.86 mg/kg) soils. In contrast, there was no significant difference in the concentration of metals in burnt and unburnt soils (P = 0.07). The order of metal concentration in the burnt soil is Fe > Mg > > Ca2+ > K > while the order of metal concentration in the unburnt soil is Fe > Mg > Ca2+ > > K > . There was also no correlation between distance and soil metal concentration (r = −0.05; P > 0.05). The result showed that burning does not negatively impact the wetland soil, rather it causes an increase in soil metal concentration probably due to the addition of ash from the burning process, which fertilizes the soil.