EFFECT OF LIQUID ANIMAL MANURE APPLICATION ON THE SOLUBILIZATION OF HEAVY-METALS FROM SOIL

The effect of liquid animal manure on heavy metal solubilization in soil has been studied in the laboratory; three different types of experiments were carried out: 1) aerobic and anaerobic incubation of soil/manure mixtures 2) desorption of heavy metals from soil, as affected by manure liquid fraction 3) gel permeation chromatography of soil/manure aqueous extracts to identify components responsible for heavy metal solubilization. All three different approaches showed that complexation involving high molecular weight dissolved organic matter from the soil/manure matrix is (together with pH) the most important driving force for heavy metal solubilization. As a consequence, chemical and microbial processes (e.g. nitrification) that influence dissolved organic matter concentrations in the soil solution, determine the degree of heavy metal solubilization in manured soil. © 1992, Taylor & Francis Group, LLC. All rights reserved.