A 3-year study was established at Melfort in the Black soil zone and at Scott in the Dark Brown soil zone in 1993 to determine optimal rates of N fertilizer for maximum economic yield (M.E.Y.) of sunola under different tillage systems. Likely because of good soil moisture conditions during the growing season, there was no difference between conventional tillage and direct seeded plots in sunola yield response to N fertilization at either location. As expected, a higher rate of N fertilizer was required to attain M.E.Y. at Melfort than at Scott because of the greater yield potential in the Black soil zone.