Mung beans (Vigna radiata (L.) Wilczek) are only inoculated in some production systems, but there is a current lack of knowledge on the best inoculants to use for effective nitrogen fixation (nodulation) and plant yields. The objectives of the present study were to determine if the dual inoculation of Arbuscular Mycorrhizal Fungi (F) and Bradyrhizobium (R) provides greater (a) mung bean yield and quality (b) nitrogen fixation for mung bean and residual soil nitrogen for the following crop, and (c) determine if these effects are consistent across various environments. Field trials were conducted in Blacksburg, VA (sandy clay loam), and Eastern Shore, VA (sandy loam), over the summers of 2020 and 2021. There were 5 treatments replicated 5 times for each variety at each site; R, F, R + F, high nitrogen (N) (100 kg ha−1), and a control, for a total of 25 plots per site. Mung beans grown in Blacksburg in 2020 and 2021 averaged 53.8% more seeds per pod than mung beans grown at the Eastern Shore. Overall yield components (seeds per pod, pods per plant) are heavily influenced by soil type. Dual inoculation significantly increased grain yield (+33%) compared to a synthetic N fertilizer application, but did not significantly increase grain yield compared to the control (+22%). Dual inoculation may increase the grain yields of mung beans compared to synthetic fertilizer regime, but does not show evidence of improving N fixation.

As United States farmers adapt soybean (Glycine max) production methods from oilseed to vegetable (edamame), key management practices will need to be considered. The key objective of this study was to determine the optimal nitrogen (N) rate and N application timing for edamame in the mid-Atlantic coastal plain system. The study was conducted for three years in Painter, VA, USA on sandy loam soils. A factorial arrangement of four N rates was applied with two application timing strategies: at-planting, and split application. Leaf tissue samples were collected and analyzed at R1. At harvest, the Normalized Difference Vegetation Index (NDVI) was measured, whole pods were mechanically collected, and yield was recorded. Additionally, pod and bean physical and chemical quality were assessed. Nitrogen fertilization significantly increased pod yield in two out of three years. R1 leaf N and sulfur (S) concentrations correlated to the yield, and R1 leaf and R6 whole-plant N concentrations correlated to the total N uptake. None of the tested parameters indicated that N fertilizer decreased yield or quality. In conclusion, we found that N fertilizer applied at planting may aid edamame yield and profit for sandy loam soils in the mid-Atlantic, USA.