An Approach to Minimize Al Toxicity in Ultisols through Organic Matter Additions

Abstract

Exploratory studies were conducted to determine the mode of action of organic matter on the immobilization of Al in an acid Ultisol. Ground coffee leaves and pangola grass were evaluated against various rates of Ca(OH)₂. Regression analyses showed correlation coefficients of over 0.91 when Ca(OH)₂, was the independent variable and exchangeable Al, pH and dry matter production were the dependent variables. An overall examination of the data reveals that acid Ultisols high in exchangeable Al inhibit plant growth and limit yields. The addition of coffee leaves decreased soil acidity and soil exchangeable Al. Coffee leaves were apparently more effective than pangola grass in inhibiting Al toxicity.