Evaluating soils phosphorus forms and distribution under different land use types

Abstract. Following nitrogen (N), phosphorus (P) is the second most important macronutrient for plant and microorganism development. Phosphorus is found in nucleic acids, phospholipids, and ATP and is required for energy transmission and cell structure. Phosphorus is also essential for biomass accumulation and primary productivity. However, it is often present in low availability forms in the extensively worn soils of tropical and subtropical regions, which has been considered one of the key limiting factors for agricultural output. Hence, the reason for this research being carried out. A total of 24 soil samples were collected from four different land uses at depths 0-15 cm and 15-30 cm, respectively, within the Kogi State University area of Anyigba with the aim of evaluating the effects of land on forms and distributions of phosphorus. The study was a 4 × 3 × 2 factorial experiment laid out in a Randomized Complete Block Design. Available P, total organic P, total inorganic P, inorganic P fractions (Fe-P, Ca-P, Al-P, Red-P and Occ/Fe-Al-P) analyses were carried out using standard procedures. The data from the laboratory analyses were subjected to three-way analysis of variance, and the means between treatments were separated using Tukey's test with a 5 % probability. The results revealed that the soils contained low levels of available P. The soil beneath forest land had the highest available P concentration (10.92 mg/kg), whereas the lowest was found in cultivated land (8.97 mg/kg). The P forms declined with depths. According to the findings, Fe-P had the highest amounts of inorganic P fractions in the research area. Lower P concentrations in cultivated land were related to lower organic matter content caused by continuous crops cultivation on the soil. Phosphorus fractions investigations are thus advised in cultivated soils to provide an adequate understanding of P status in the soil and fertilizer recommendations to boost productivity.