SPATIAL VARIABILITY OF SOIL ORGANIC CARBON, TOTAL NITROGEN AND SOIL pH IN SOILS OF WUKARI LOCAL GOVERNMENT AREA TARABA STATE, NIGERIA

This study was conducted in Wukari Local Government Area to examine spatial variability of Soil organic carbon (SOC), total nitrogen (TN) and pH using Geographic Information System (GIS) technique and ordinary Kriging interpolation method. A coordinated data collection scheme was designed using global positioning system (GPS) in such a way that the entire area was divided into grids of 155 blocks out of which a total of 108 augured samples were collected at the depth of 0-20cm. All samples collected were analyzed following standard analytical procedures. ArcGIS Desktop 10.5 Geostatistical wizard was used in the creation of the models. The data were processed with Normal QQ plot and Global trend analysis to provide an acceptable data for ordinary kriging modeling, semivariogram analysis fitted into Gaussian model was used to test the spatial dependence of the Soil organic carbon (SOC), total nitrogen (TN) and pH. Spatial distribution maps and soil fertility maps showing areas of low, medium, and high concentration were developed. The QQ plot showed normal distribution for SOC and TN while pH was transformed using log transformation, global trend was observed in all the parameters and trend remover was applied. The fitted semivariogram showed strong spatial dependence for SOC (0) and moderate for TN (0.51175) and pH (0.463919). The interpolated maps show low to medium content of SOC and TN while, the pH was moderately acidic to slightly acidic.