The effects of diverse cropping systems on aggregation of a Luvisolic soil in the Peace River region

Aggregate distribution and stability of surface soil were determined for different cropping systems of a Luvisolic soil in the Peace River region of Alberta. Gray Luvisolic soils have inherent problems that include weak platy structured surface horizons which are underlain by compact sub-soils. The cropping systems consisted of (i) continuous barley (CB) (Hordeum vulgare L.); (ii) barley/forage (BF), 3 yr of barley followed by 3 yr of forage (mixture of bromegrass [Bromus inermis Leyss] and red clover [Trifolium pratense L.]); (iii) continuous grass (CG) (bromegrass); and (iv) continuous legume (CL) (red clover). The barley/forage rotation consisted of two phases, the barley phase (BF) and forage phase (BF). Each phase was present every year. Aggregate separation by dry-sieving with a rotary sieve indicated that the CL cropping system had fewer large aggregates and more small aggregates than the other cropping systems. The CG, BF and CB cropping systems had more larger aggregates and were similar to each ...