Comparison of Adsorption Models for Determining Potassium Behavior of Some Selected Soil Series

  • Nabeel Rizwan
  • Qudrat Ullah Khan Department of Soil and Environmental Science

Abstract

Potassium (K) availability to plants varies with the adsorption characteristics of soil, to evaluate
the adsorption capacity, five soil series of different characteristics were used. K adsorption
isotherms were performed by equilibrating 2.5 g soil samples with 10 levels of K (30-300 mg kg-1)
as KCl in 0.01 CaCl2 solutions and shaken for 24 h at 25oC. The amount of K adsorbed ranged
from 33.2 to 94.9% of added K. Freundlich model explained K adsorption behavior better than the
other two equations. Higher coefficient of regression values 0.99, 0.97 and 0.96 were recorded in
Sultanpur (Silt loam), Naivela (Fine sandy loam) and Bhutesar (Clay loam), respectively. The
highest 1/n value 1.54 kg mg-1 and kf value 31.47 mg kg-1 of Freundlich isotherm were observed
in Sultanpur (silt loam) due to high pH, high OM and high clay contents, lowest values of
constants were observed in Wajan (loamy sand) with 1/n value 0.44 kg mg-1 and kf value 0.28 mg
kg-1 might be due to high EC, high CaCO3 and sand contents. The K adsorption of soil varied with
physico – chemical characteristics of soil, especially clay content, alkaline pH and organic matter
content.

How to Cite
RIZWAN, Nabeel; KHAN, Qudrat Ullah. Comparison of Adsorption Models for Determining Potassium Behavior of Some Selected Soil Series. Pakistan Journal of Analytical & Environmental Chemistry, [S.l.], v. 22, n. 1, p. 74-83, june 2021. ISSN 2221-5255. Available at: <http://pjaec.pk/index.php/pjaec/article/view/653>. Date accessed: 29 july 2021. doi: http://dx.doi.org/10.21743/pjaec/2021.06.09.