Despite cultivar improvements, crop damage due to cold temperatures remains a concern. Frost, and near-freezing conditions in spring and fall can damage soybean. Early planting in cool and wet conditions can reduce germination, increase seedling disease and reduce plant stand, while late planting has been shown to reduce yield and quality. Potential may exist to reduce the risk associated with frost and/or near-freezing conditions through management: proper choice of planting date, and management of preceding crop residue, may also influence early-season temperatures and crop growth.
Two small-plot studies were initiated at each of Brandon, Carberry, Portage and Roblin, MB in 2014. Study 1 investigated the effect of soil temperature (cold, control, warm) at different planting dates (early, late) on soybean. Data collected included emergence date, plant density, crop growth stage periodically through the growing season, early-season biomass, seed yield, seed quality, and soil temperature and moisture content. Effects of soil temperature treatments on yield varied among sites, and did not appear to be consistently related to soil temperature at seeding. Study 2 investigated the effect of residue management on a subsequent soybean crop. Residue management influenced soil temperature at seeding at all sites in 2015. The average soil temperature of treatments where straw was retained on the soil surface was approximately 1 to 3 °C lower than those where straw was removed. Despite these early-season differences, residue management had limited effects on plant stand, soybean yield, and seed quality including test weight and seed weight in 2015.