Stability and Settling of Soil Aggregates Treated with Polymers under Different Degrees of Disruptive Forces

The degree of stability of a sandy loam soil treated with different organic polymers was evaluated by dry and wet sieving and wet shaking techniques. In general, all conditioners improved aggregation. Polyvinyl alcohol (75,000 mol. wt) and bitumen emulsion treatments imparted a high degree of stability to the aggregates under wetting, whereas the improvement was only moderate with polyacrylamide and polyvinyl acetate. Under wet shaking conditions, the geometric mean weight diameter decreased in the order, non-ionic polymers, ionic polymers and emulsion treatments.

Use of polyvinyl alcohol and polyacrylamide (anionic) resulted in little settling of aggregate (1–2 mm) columns and high saturated hydraulic conductivity. Higher column height with uniformly smaller aggregate size under untreated and gypsum treatments did not show higher hydraulic conductivity values. Treatment with polyacrylamide (cationic and non-ionic) and polyvinyl acetate emulsion resulted in high settling and moderate degree of conductivity.