Kinetics of Competitive Fixation of Potassium and Ammonium Ions by Silt Component of Soils from Different Agro-Climatic Regions

ABSTRACT

Potassium (K⁺) and nitrogen [N, as the form of ammonium (NH₄⁺)] are major nutrients for plant growth. Although there have been a number of studies on the kinetic fixation of potassium and ammonium ions in soils and clays, however, investigations on the kinetics of competitive fixation of these ions have been few, if any, especially by taking into account silt component of the soils. In this study, the kinetics of potassium and ammonium fixation were examined in the silt components of several soil samples. The results revealed that considerable amounts of K⁺ and in lesser amounts, NH₄⁺ ions were fixed by silt components of the soils. Potassium fixation was strongly preferred over ammonium. To describe the fixation kinetics, seven mathematically models were evaluated. A comparison of the models showed that pseudo-second-order equation properly described the fixation of these ions by the silt components.

KEYWORDS:

• Ammonia volatilization
• mineralogy
• pseudo-second order