Optimal management practices of grain corn production under rainfed conditions in southern Alberta

Short-season corn (Zea mays L.) hybrids have expanded grain corn production in the Canadian Prairies, but information on management practices is limited. We conducted four separate experiments, collecting 6-9 site-years of data per experiment across seven locations in southern Alberta between 2015 and 2022, to determine productivity and optimal agronomic management for grain corn production under rainfed conditions. During this period precipitation was generally below average (-40% to +20%). Corn planted at narrow-row spacing (51 cm apart) showed better emergence (+12%) and yield (+15%) compared to wider-row spacing (76 cm apart). Increasing plant population density resulted in increased grain yield (up to +28%) in site years with normal to high precipitation. However, seeding rate had no significant effect on grain yield under low precipitation conditions. Similarly, nitrogen fertilization rate and application timing had marginal effects on corn yield, with reduced seedling emergence and development, and grain yield (up to -6%) at fertilizer rates exceeding 113 kg N ha-1, which is likely related to the predominately low moisture conditions during the study. Zero-till practice led to a reduction in plant establishment (up to -25%), but yielded similarly to conventional tillage. Earlier seeding did not impact grain filling or yield. The late maturing corn variety was taller (+10cm) and took 6 days longer to reach tassel and silking stage, but these traits had no impact on grain yield. This study indicates that high seeding rates (above 60,000 seeds ha-1) can lead to high grain yields (over 4.24 Mg ha-1) with fertilization between 113 kg N ha-1 and 169 kg N ha-1.