COMPARATIVE EFFECTIVENESS OF WATER, CALGON AND SODIUM HYDROXIDE IN SOIL DISPERSION UNDER TWO MECHANICAL AGITATION METHODS

Abstract

Distilled water, 5% calgon and sodium hydroxide were used as dispersion agents in the particle size analysis of surface and subsurface soils of five Nigerian soils. Sampling depths were 0 – 15, 15 – 30 and 30 – 45cm and concentrations of sodium hydroxide were 0.2N, 0.4N and 0.6N respectively. Agitation methods were high speed mechanical stirring for five minutes, and overnight shaking on a reciprocate shaker. Water was found to be least effective in soil dispersion, regardless of sampling depth or agitation method. There was no significant difference between the effectiveness of calgon and different concentrations of NaOH (p= 0.2866). There was also no significant difference between the two agitation methods within each soil depth. There was however highly significant interaction between soil depth and agitation method (p<0.01) and also between soil depth and dispersion agent (p< 0.05). Overnight shaking was more effective on soils of 0 –15 and 15 –30cm depth, but mechanical stirring for five minutes was more effective at 30 –45 cm depth. NaOH was as effective as calgon at 0 –15 and 15 – 30cm, but calgon was significantly more effective than NaOH at 30 – 45cm.



[Niger Agric. J. 34 (2003): 19-26]