Treatment 1 reflected common farmer practice. Subsoiling (treatment 3) was introduced
in the hope that it might increase infiltration, so reducing runoff and soil erosion. It was
carried out each year after the soil had been softened by pre-planting rains. Depth of
subsoiling was 0.5 m. Whilst not currently a common practice, treatment 4 of no tillage
(other than the minimum required for planting) was introduced because of its soil conservation
potential.