Desorption of phosphate(V) ions from brown soil

Abstract

The objective of the study was to determine, under laboratory conditions, the rate of phosphate (V) ions leaching down brown soil horizons under the influence of redistilled water of pH 6.2. Laboratory tests were conducted to determine the effect of mineral and organic fertilization on phosphate (V) ion concentrations in brown soil horizons before and after extraction with water. The content of desorbed PO4 3– ions was determined in percolating water samples. The results indicate that the quantity of desorbed phosphate (V) ions was affected by the type and rate of fertilization as well as by the dose of the applied solvent. The highest desorption of phosphate (V) ions from the brown soil profile was reported in the treatment fertilized with manure + PK, while the lowest desorption was observed in the plot fertilized with NPK. The maximum desorption of phosphate (V) ions was noted in soil layers at the depths of 0-25 cm and 26-50 cm. In all filtrate samples, PO 4 3– values significantly exceeded the minimum quantity required to initiate eutrophication. The highest content of phosphate (V) ions, at 64.8 mg PO 4 3–⋅kg–1 soil, was determined in percolating water from the treatment fertilized with slurry rate II (123.8 t⋅ha –1 ). Percolating water samples collected in the non-fertilized (control) plot were least abundant in phosphate (V) ions (21.7 mg PO4 3– ⋅kg –1 soil).