IMPROVED PREDICTION OF WATER-RETENTION PROPERTIES OF CLAYEY SOILS BY PEDOLOGICAL STRATIFICATION

The water‐retention properties of clayey soils have been studied at −0.3 × 105 and −15 × 105 Pa matric potentials using three sets of clayey horizons differing in their pedological origin. Measurements were made on small clods collected in winter when swelling is at a maximum. The results are discussed in relation to variations in the clay content and clay fabric. The bulk volume, which appears to be closely related to both clay content and clay fabric, allows the variations in water retained to be explained better than with clay content alone. With clayey horizons originating from a single soil family, differences in water retained can be explained by variations in clay content alone because clay fabric does not change greatly. These results demonstrate the significance of pedological stratification in estimating the water‐retention properties when a single soil characteristic, such as clay content, is used. Copyright © 1990, Wiley Blackwell. All rights reserved