Evaluation of potassium release and fixation behaviour of some Nigerian soils

Abstract

In this study, K fixation and release parameters estimated for 25 Nigerian soils both by the conventional fixation methods and the electro-ultrafiltration (EUF) technique were related to some soil physico-chemical properties. This was to ascertain the suitability of the EUF to comprehensively characterize K dynamics in the experimental soils. Potassium fixation was higher and varied more under “wet”-condition (12.28-28.14 cmol kg^-1) than under “wet-and-dry”-condition (5.63-14.33 cmol kg^-1), representing 24.60-56.28% and 11.26-28.66% of fertilizer-K added. The fixation data obtained under “wet-and-dry”-condition, however, reflected K dynamics is the soils better than that of the “wet”-condition. Potassium desorption by EUF technique after 10 and 35 minutes, representing the intensity and quantity factors, ranged between 0.1 – 0.28 and 0.08 – 0.91 cmol kg^-1, respectively with mean values of 0.08 and 0.20 cmol kg^-1. The superiority of the EUF technique to provide the needed information on soil K dynamics better than the methods normally employed in fixation studies was demonstrated in this study.

Nigerian Journal of Soil Science Vol. 15 2005: 47-53