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Shafiqur Rahman
Assistant Professor
Department of Soil Science, University of Dhaka, Bangladesh.

Abstract/ Executive Summary:

Effect of Na, Ca and Mg concentration on soil permeability was studied under laboratory conditions. Two size fractions <0.5 mm and <0.25 mrn) of the soil were used. Chloride solutions of Na, Ca and Mg were used as saturating and also as diluting electrolytes. Soil permeability was measured as an index of effect of electrolyte concentration. Na was found to be most and Ca to be least effective in reducing permeability. The effect of Mg was found to be in between Na and Ca <0.25 mm soil fraction was found to be more sensitive to a decrease in electrolyte concentration than the <0.5 mm soil.

Keywords: Soil, Fertilizer, Na, Ca and Mg

Location: Department of Soil Science, University of Dhaka, Bangladesh.

Start Date:

End Date:

Program Area: Crop-Soil-Water Management

Commodity: Soil fertility

Objectives:

To investigate the effects of Na, Ca and Mg concentration on soil permeability and to compare the effect of Mg to that of Na and Ca.

Methodology:

The soil used in this study was collected from the B horizon of the Sonning series from the Reading University farm, England. A typical soil of the Sonning series is non-calcareous, sandy loam, freely drained and brown to greyish brown in colour. A mineralogical analysis of the <1. 4 mm size fraction separated by sedimentation showed the presence of llite (75- 80%), Kaolinite (10-15%), Montmorrilonite (5%) and Goethite.

The experiment was carried out almost in an identical way as described by quirk and Schofield (1955) with slight changes. A cylindrical perspex permeameter with an 80 mesh copper gauze at the base was used. 20 g of 0.5-1 mm sand were poured into the solution in the permeameter followed by 60 g soil. The soil was uniformly settled by tapping the permeameter. The soil was then covered with a disc of whatman NO.1 filter paper on top of that to avoid disturbance when solutions were being added to the permeameter. The leaching of the soil was started by inverting a flask filled with a saturating solution carefully on top of the soil bed. The soil was allowed to leach overnight with the concentrated solution at a flow rate as minimum as possible. On the following morning leaching was continued with the same saturating solution. This time the pressure head was adjusted to give a flow rate of about 4.2 ml/minute. Flow rates were measured at 30 minute intervals. Leaching was continued in this way for 2 hours. More dilute solutions were then used and flow rates were measured at 30 minute intervals as before and it was continued for another 5 hours.

Source of Information: Bangladesh Journal of Agriculture,Vol-3, No-1, Pag: 308-312, June-1978

Article Link (Online Journal):

Funding Source:

Total Budget (Tk.) :

Achievement/Findings:

Na was found to be most and Ca to be least effective in reducing permeability. The effect of Mg was found to be in between Na and Ca <0.25 mm soil fraction was found to be more sensitive to a decrease in electrolyte concentration than the <0.5 mm soil.

Knowledge Management: Journal