Fractionation of Inorganic Phosphorus in Nitisols of Welmera District, Ethiopia

Abstract

The phosphorus fractionation process has been commonly used to investigate soil forms of inorganic P (Pi) and transformation of applied P chemical fertilizers, which is important for agronomic management of phosphorus and water quality related issues. In an attempt to understand phosphorus forms in soils, an experiment was carried out in 2018 to measure the amount of Pi contained in acidic Nitisols in various forms. Surface agricultural field soils (0 - 0.20 m depth) were sampled with at least 5 auger samples composited to one and bulked to form one composite per location from four representative acidic soils. The soils are sandy clay loam with a low to medium organic carbon content and a very strongly to extremely acidic soil reaction. According to the soil Pi fractionation results, the Al-p, Fe-P content exceeds the easily soluble P with high exchangeable acidity, whereas the Ca-P level is zero. The low avaible P supply creates the limitation of crop production. To bring these soil in good condition, integrated application of aglime with organic materials is required to release P from various pools, that results the beneficial changes for most of the soil chemical properties.