Properties of rainfall induced crusts in alluvial soils and their effect on modulus of rupture

Abstract

Crust and bulk soil samples, collected from a semi-arid region, were analysed for different properties. Crust samples had higher clay, silt, water dispersible silt plus clay, bulk density and cation exchange capacity (CEC) than the soil below the crust. Modulus of rupture (MOR) as determined on distributed crust material, showed better correlations with textural parameters viz. clay (r = 0.70), silt (r = 0.68), silt + clay (r = 0.82) and fine sand (r = -0.81) than with other parameters like CEC (r = 0.53), ESP (r = 0.55), exchangeable magnesium percentage (r = 0.46) and exchangeable calcium percentage (r = -0.44). Multiple linear regressions between MOR and different crust parameters showed that clay, silt and ESP accounted for 84.1% variation in MOR in these soils.