Planting depth and seed size affect edamame emergence individually

Abstract

Edamame growers currently rely heavily on planting depth recommendations for grain-type soybean, despite stark differences in seed characteristics between the two types of cultivars, most notably seed size. Therefore, the objective of the study was to determine the effects of planting depth and seed size on edamame emergence. A popular edamame cultivar used in commercial production was sorted into '‘small’' (23.7 g/100- seed) and '‘large’' (36.8 g/100-seed) seed-size classes, then planted at depths of 1.0, 2.0, 3.0, and 5.0 cm in field experiments. Experiments were conducted in four environments as a split-plot experimental design with four replications. Seed size did not influence total emergence; however, small seed emerged 10% faster than large seed. Although planting depth recommendations for grain-type soybean are 3.2 to 4.5 cm, our results showed edamame emerged more completely and quicker at the shallowest depths examined. The research could be expanded to capture greater diversity in growing environments and crop cultivars; however, the vegetable industry now has research-based information to guide preliminary recommendations regarding appropriate planting depth of edamame.