Rotation ABC – Lethbridge, Alberta.

Rotation ABC was established in 1911 at the Lethbridge Research Centre. The rotation study has been and continues to be used to evaluate the long-term impacts of cropping systems on soil quality, productivity, and the broader environment. The non-replicated study includes three wheat-based rotations, rotations that were considered feasible in western Canada. The rotations were continuous wheat (A), fallow-wheat (B), and fallow-wheat-wheat (C). In 1967 and 1972 the plots were divided to impose four fertility treatments within each plot by applying all combinations of two rates of nitrogen and phosphorus fertilizer. In 2010, six plots of Rotation T, land adjoining Rotation ABC and in a fallow-wheat rotation since the 1950’s, were used to replicate Rotation ABC. Associated with the rotation are the Chemist plots. These were smaller plots with the same crop rotations and fertility treatments (fertility treatments delayed until 1992) as Rotation ABC. The Chemist plots were established for detailed soil analyses by the chemists located in Ottawa. Originally the Chemist plots also included rotations M, S and T but these three plots were allocated to other studies.