THE EFFECTS OF ADDITIONS OF CaCO3 AND P ON THE SOIL SOLUTION CHEMISTRY OF A PODZOLIC SOIL

Abstract

The surface horizon from a Humo-Ferric Podzol was amended with both CaCO3, and P to investigate the changes in the ionic composition of the soil solution and the charge characteristics of the horizon. Addition of CaCO3 increased the concentrations of Ca and [Formula: see text] and decreased the total concentrations of Mg, Na, K, Al, Zn, Mn, Si and [Formula: see text] in the soil solutions. In addition, the pH of the soil solutions, the content of negatively charged sites on the soil surfaces, the relative proportion of Mn2+ and Zn2+ of sulfate ion pairs were raised. In contrast, the concentrations of exchangeable Zn and Mn, the amount of positively charged sites and the proportion of metals linked with the "modelled" fulvate ligands were reduced. The addition of increasing rates of P reduced the total concentrations of Mg, K, Al, Si, and the concentrations of [Formula: see text] and [Formula: see text] in solution but did not affect the pH or the CEC of the soils appreciably. The concentrations of Si, phosphate-P, [Formula: see text] and of the sulfate ion pairs in solution were increased by increasing P additions to the soil. Key words: Liming, phosphorus fertilization, soil solution, GEOCHEM, ion speciation