Seasonal Variation of Soil Resistivity and Soil Temperature in Bayelsa State

Problem statement: Due to the climatic variation for the year and it's sever harmattan during the month of December to March with the high keraunic level (80-90) in the areas, it was necessary to know the seasonal variation of soil resistivity. The seasonal variation and the nature of soil have considerable influence on electrical characteristics and therefore affect the earthling system performance. Approach: Eighteen sites were chosen from three main soil divisions. The soil resistivity was taken in each of the site at depths of 0.5, 0.8 and 1.2 m using the four point test instrument (Wenner Method). From the selected sites in the three soil divisions the temperature was also taken at depths of 0.2, 0.5, 0.8 and 1.0 m. Results: The coefficient of seasonal variation at the depth of 0.5 m was high and reduced drastically at a depth of 1.2 m. The soil temperature was higher than the ambient temperature at the depth of 0.2 m during the months of December to March. From 0.8 m depth and below the temperature reduced even during the dry seasons. Conclusion: The coefficient of seasonal variation of soil at the depth of 0.8 and 1.2 m was small (1.8-3.0) throughout the year in all soil types. That indicates the high water level and or the permanent moisture table which gives an advantage to low soil resistivity for buried conductors and electrodes in the area.