Shrinkage characteristics of soil clods from a grey clay under intensive cultivation

Abstract

Structural degradation in a grey clay under intensive cropping was investigated by studying the shrinkage characteristics of soil clods collected from the field. Soil clods with different cropping histories differed in the amount of structural shrinkage relative to normal shrinkage. Soil clods (c. 50 cm3) from the irrigated site were found to have a smaller degree of structural shrinkage than those from the dryland wheat site, resulting in higher bulk density and lower air-filled porosity. The 'degraded' soil clods remained almost saturated with water over the available moisture range.