INFLUENCE OF LAND USE TYPES ON SOIL MICROBIAL POPULATION AND FERTILITY IN AKURE, NIGERIA USING GEO-SPATIAL TECHNOLOGY

Abstract

The influence of land use types on soil microbial population was conducted at the Teaching and Research Farm of the Federal University of Technology Akure Nigeria, (7018’N, 507’E) in 2015. The aims of the study were to identify the effects of land use types on soil microbial population and fertility using geospatial technology. The experimental design used was a split plot with land use types as the main plots while soil depths formed the subplots. The land use types identified on the GeoEye-1 satellite image were oil palm, teak, uncleared forest, cassava, sugarcane and the three soil depths (0-15cm, 15-30cm and 30-75cm).The feature extraction technique in Arc GIS was used to group and delineate the land use types. Soil samples at seven locations were taken from each land use and analysed for pH, nitrogen, phosphorus, potassium, calcium, magnesium, sodium, cation exchange capacity, exchangeable acidic and organic matter. The spatial nutrient concentration across the land use types and the microbial population was generated using the GIS IDW technique of 3D Analyst/ Tools while the fertility map was generated using the overlay operations of 3D/Raster Math Tools in ArcMap. The fertility map generated indicated high fertility status in the uncleared forest and teak, while the oil palm land was of medium fertility and cassava and sugarcane land was of low soil fertility. The data on the colony forming unit (cfu) of the microbial population was subjected to the square root transformation in Statistical Package for the Social Sciences (SPSS) software. The mean values of the soil chemical and biological properties were subjected to analysis of variance (ANOVA) test and means compared using Duncan Multiple Range Test at 5 % level of probability. This study revealed that spatial distribution of Nitrogen concentration in surface and subsoil was high in teak plantation, sugarcane and cassava compared to other land use types while the phosphorus concentration, potassium concentration, calcium concentration in the surface and subsoil was high in uncleared forest, oil palm, teak plantation compared to other land use types. The magnesium concentration in surface and subsoil was high in oil palm, cassava and sugar farm, organic matter concentration in surface and subsoil was high in teak plantation while CEC concentration in surface and subsoil were high in oil palm, cassava, sugarcane and teak plantation.