2019 ASHS Annual Conference

Consumer demand for edamame, the vegetable version of soybean, has grown the last decade in North America. Domestic production of edamame is on the rise; however, research to guide fundamental crop production practices is lacking, including knowledge useful for developing appropriate recommendations for crop seeding rate. Field experiments near Urbana, Illinois were used to quantify edamame response to plant density and determine the economically optimum plant density (EOPD) of machine-harvested edamame. Crop growth and yield responses to a range of plant densities (24,700 to 395,100 plants/ha) were quantified in four edamame cultivars (AGS 292, BeSweet 292, Gardensoy 42, and Midori Giant) across two years. Plots were harvested with the Oxbo BH100, a fresh market bean and pea harvester. Assumptions for the economic analysis included a seed cost of $38/kg and wholesale price of frozen podded edamame of $6.60/kg. In general as plant density increased, branching and the ratio of pod mass to vegetative mass decreased, while plant height and leaf area index increased. Recovery, the percent of marketable pods in the machine-harvested sample, varied among cultivars from 86 to 95%. Initial findings identified the EOPD for machine-harvested edamame averaged 88,000 plants/ha, resulting in an average maximum marketable pod yield of 5.2 Mt/ha. When considering seed costs, marketable pod yield, and recovery, edamame EOPDs are considerably lower than recommended seeding rates of up to 344,200 seed/ha observed in some recent publications.