ROW SPACING AND SEEDING RATE EFFECTS IN WHEAT AND BARLEY UNDER A CONVENTIONAL FALLOW MANAGEMENT-SYSTEM

Varying seed row spacing had no effect on the yield of spring wheat (T riticum aestivum L.) or barley (Hordeum vulgare L.) when grown under a conventional-tillage fallow-management system. Grain yields were impr oved with increased seeding rates by 14% in wheat and 32% in barley. T he absence of a row-spacing-by-seeding-rate interaction suggests that adjustments in seeding rates are not required with changes in row spac ing. The presence of surface residues and standing stubble cannot expl ain the lack of a row-spacing effect when using a zero-tillage stubble -cropping system, since similar results were obtained with a conventio nal-tillage fallow management system in this study.