A comparison of soil aggregate stability tests using soils with contrasting cultivation histories

Abstract

Abstract A turbidimetric test and two wet sieving tests were used to measure aggregate stabilities of soils from five neighbouring fields with different cropping histories. Turbidimetry more clearly reflected differences in cropping history than either wet sieving procedure, and was also more rapid and reproducible. Wet sieving with slow wetting was a more sensitive indicator of small differences in stability of unstable soils than sieving after rapid wetting. The tests involving rapid wetting revealed differences among fields related to cropping history and organic carbon content. The small differences in clay and plastic limit moisture contents of the fields were not clearly reflected by the results of all the tests. Clay content correlated significantly only with the slow wetting test, moisture content at the plastic limit only with turbidimetry, although this latter relationship is probably not causal, but may reflect control of both variables by organic carbon.