Planting progress has been slow over the last week although a few areas did make headway. Less than 10% of the crop has been planted to date. Soil potassium levels have slipped in Ontario with estimates that up to 20% of Ontario fields may be below ideal levels for soybeans. Applying potassium in the spring before planting is an acceptable practice for fields with low soil test levels. Any field with less than 10 ppm K in soil test results may suffer significant yield losses, especially in dry years. A 50 bu/ac crop removes about 70 lbs/acre of potassium. Glyphosate burndowns should be applied 5-7 days before planting to ensure adequate translocation into perennial weeds. If perennial weeds are getting large (12.5 cm (5″) or taller), increase the rate of glyphosate. If annual weeds are the target, a 3 day pre-plant interval is adequate.
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