Geostatistical investigation and GIS-based spatial distribution of some micronutrients in Wukari soils, Taraba State, Nigeria

Mapping soil fertility is important for site-specific nutrient management, it gives an insight into soil nutrient content, which is crucial for land use planning, fertilizer recommendations, and sustainable management of soil resources. Micronutrient deficiency in the soil is a serious limitation for crop production. Evaluation and mapping the soil micronutrients of a particular area can be a possible solution to mitigating its deficiencies, as they will serve as a guide for nutrient management. A study was conducted in Wukari to quantify and visualize the distribution of pH, manganese, iron, and zinc within the study area. Soil samples were collected from 98 locations. The samples were analyzed for soil reaction (pH), manganese (Mn), iron (Fe), and zinc (Zn). A spatial map for pH, Mn, Fe, and Zn was developed through geostatistical analysis using an ordinary Kriging interpolator. The soil pH is slightly acidic to slightly alkaline (5.3 to 7.6), available manganese (0.01 to 13.97 mg/kg) with mean value of (3.00 mg/kg), available iron (0.43 to 21.20 mg/kg), with a mean value of 11.15 mg/kg, and available zinc content (0.04 to 15.27 mg kg1) has an average of 1.96 mg/kg. Based on the soil test results, the spatial variation of pH, Mn, Fe, and Zn was prepared. The spatial correlations (ranges) of soil properties varied from 8933.50 m for zinc to 16349.81 m for iron. The nugget/sill ratio of the semi-variogram model showed moderate spatial dependence for pH, manganese, and zinc (0.51, 0.59, 0.47), and weak spatial dependence for iron (0.85).