Effects of Land Use on Forms of Phosphorus in Coastal Plain Sands of Nigeria

This research studied the effect of land uses changes on the forms of phosphorus within the coastal plain sands landscape of southeastern Nigeria. Satellite imageries and soil data including phosphorus fractions were used for the study. Spatial coverage of forest and agricultural (fallow and farmland) land uses, accompanying soil properties and forms of phosphorus were estimated. There was progressive increase in the agricultural land use over the years to as much as 85.7% of the study area. The agricultural land use continually undergoes circles of crop-fallow with accompanying influence on nutrient cycling and pedogenesis. Land uses studied influenced available, organic, total, bound, iron and occluded iron and aluminium forms of phosphorus whereas topography influenced iron forms. Particle size distribution influenced available, organic, total, bound iron and occluded forms of phosphorus. Soil pH influenced available and iron forms of phosphorus whereas organic matter is a major determinant in the distribution and variability of iron, occluded, occluded iron and aluminium, calcium and residual forms. Progressive increases in the spatial coverage of agricultural land use under the present production system results to preponderance of recalcitrant phosphorus in larger portion of the study area to the detriment of available forms, crop growth and yield.