IMPACT DAMAGE TO SOYBEAN SEED AS AFFECTED BY SURFACE HARDNESS AND SEED ORIENTATION
ABSTRACT Soybean seeds at four moistures were impacted using three impact surfaces, four impact velocities, and five seed orientations. A steel impact surface caused the most damage (41% germination, 54% cracks or splits) and a soft polyurethane surface caused the least (87% germination, no cracks or splits). Seed damage increased as impact velocity increased from 10 to 40 m/s. Damage decreased as seed moisture content increased from 7.2 to 16.2% when a steel impact surface was used, but increased with moisture when a polyurethane surface was used. Impacts to the side of the seed cotyledon produced the least damage (67% germination, 25% cracks or splits) while impacts to the back (opposite the hilum) of the seed produced the most damage (57% germination, 35% cracks or splits). Impacts to the hilum and hypocotyl resulted in tissue damage in the germinated seedling.