Approximately 5% of the overall acreage has been planted. Once fields dry planting will start in earnest. There is no reason to wait at this date even if soil temperatures are cool. The yield benefit of early planting generally outweighs the risk of planting into cold soils. Seeding rate recommendations are significantly lower in some US states. Keep in mind that many of these are based on using a planter and those regions have more heat units than Ontario. Soybean seeding rates for Ontario were updated a few years ago based on 45 replicated field trials. The most economic seeding rates forOntariobased on experimental data from 2005-2007 are: 194 000 seeds/acre in 7.5” rows. 177 000 seeds/acre in 15” rows seeded with a drill and 165 000 seeds/acre in 15” rows planted with row unit planter. It is possible to achieve high yields with lower seeding rates but plants must be evenly distributed and field conditions ideal. In dry years when plants are short very low plant stands can significantly reduce yields.
Written by Horst Bohner
Areas of Focus • Soybean production techniques including variety, tillage, disease and fertility management • Collaborate on applied research and demonstration projects to improve soybean production in Ontario