Planting depth and seed size affect edamame emergence individually

Authors: CRAWFORD, LAURA - University Of Illinois; Williams, Martin

Submitted to: HortScience
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/31/2018
Publication Date: 1/1/2019
Citation: Crawford, L.E., Williams, M.M. II. 2019. Planting depth and seed size affect edamame emergence individually. HortScience. 54(1):92-94. https://doi.org/10.21273/HORTSCI13631-18.
DOI: https://doi.org/10.21273/HORTSCI13631-18

Interpretive Summary: Edamame is a specialty food-grade version of grain-type soybean which has larger seeds that are considerably more expensive than grain-type soybean. Growth in U.S. demand for edamame has increased domestic production of the crop; however, best agronomic practices for growing the crop are limited by lack of research-based information. For instance, an aspect as simple as optimal seeding depth in the soil is unknown for edamame. This research determined optimal seeding depth for multiple seed-size classes of edamame. Results show that all seed size classes of edamame should be planted more shallow than grain-type soybean. Growers and vegetable processors now have research-based guidelines to help determine edamame seeding depth. Such information will improve edamame emergence, a foundation for economically viable production of the crop.

Technical 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 four times 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. While 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. While the research could be expanded to capture greater diversity in growing environments and crop cultivars, the vegetable industry now has research-based information to guide preliminary recommendations regarding appropriate planting depth of edamame.