Effects of Concentration of Sodium Hexametaphosphate and Dispersion Period on the Dispersability of Three Alfisols at Samaru, Northern Nigeria.

Abstract

Strongly aggregated Soils are not readily dispersed with the standard 5% Calgon (sodium hexametaphoshate (SHMP) solution, under the 5- minute shaking or 1- minute stirring (dispersion) periods. The feasibility of better dispersion at higher SHMP concentrations and/ or longer dispersion periods was, therefore, explored on three Alfisols with differing drainage classes, namely, a well drained Oxic Haplustalf, a moderately well drained Typic Plinthastalf ,and a poorly drained Aquatic Haplustaff. To concurrently determine both the most effective SHMP concentration and a dispersion periods, graded concentrations of SHMP, viz: 5%, 7.5%, 10%, and 12.5%, and five dispersion periods of 5 minutes, 30 minutes, 1 hour, 2 hours and 3 hours were applied. The results showed that the 5- minute dispersion period remains ideal for the three Alfisols. However, the effect of SHMP concentration varied; the well drained Oxic Haplustaff required double the standard concentration from 5% to 10%, the moderately well drained Typic Plinthustalf, a 50% increase to 7.5%, while the poorly drained Aquatic Haplustaff, just the standard (5%) SHMP concentration for effective dispersion.

Nigerian Journal of Soil Science Vol. 17 2007: pp. 1-9