Iron deficiency chlorosis risk. Recent research studies have confirmed the value of very high seeding rates in reducing chlorosis symptoms.
Tillage / residue cover / seedbed condition. No-till systems provide a less hospitable environment for soybean emergence due to colder soils, more residue, and possible seed placement / soil contact challenges. Cloddy soils may also reduce seed-soil contact.
Seedling disease risk. Some regions have higher seedling disease risk due to soil types, weather patterns, and pathogen race shifts. Higher seeding rates are needed to establish target stands in areas or fields with a history of higher disease risk.
Soil type. Soils with high clay content are much more likely to crust and restrict soybean emergence, and also promote seedling diseases in wet springs.
White mold risk. In fields with a historically high risk of white mold, very high seeding rates are not recommended.