Temporal variation in aggregate stability on conventional and alternative farms

Temporal variations in aggregate stability were measured at three slope positions on soils from adjacent farms managed for many years using conventional vs. alternative tillage and crop rotations. Aggregate stability on both farms decreased significantly from October to March in response to precipitation and cycles of winter freezing and thawing. Significant increases in stability occurred from March to June on both farms; these were interpreted in terms of recovery of cohesion by aggregates following their disruption during the winter. Differences in stability resulting from management practices on the two farms were not significant, even though organic C contents on the alternative farm were significantly higher. -from Authors