Evaluation of Soybean (Glycine max) Yield and Quality Following Delayed Harvest Conditions.

Soybean growers in the mid-southern U.S. face many challenges throughout the growing season. One example is a decrease in seed/grain quality due to delayed harvest that may develop following adverse weather conditions. During these events, the environment becomes conducive for moisture to enter the pod or for pathogens to spread, both of which may contribute to decreased quality of seed/grain. The objective of this research is to evaluate seed/grain quality as it relates to delayed harvest conditions for soybean treated with fungicide to mitigate spread of pathogens or harvest aids to facilitate more efficient harvest.

Experiments were conducted in 2019 at the R.R. Foil Plant Science Research Center (Starkville, MS) and the Delta Research and Extension Center (Stoneville, MS). Soybean was planted at two planting dates and treated with either fungicide (Quadris Top SBX, Miravis Top, or a tankmix of Priaxor plus Domark) or harvest aids (Gramoxone SL 2.0, Defol 5, or a tankmix of Gramoxone SL 2.0 plus Defol 5). Fungicides were applied at the R4 growth stage while harvest aids were applied at the R7 growth stage. An untreated check was included with each fungicide and harvest delay or harvest aid and harvest delay combination. Harvest commenced on time and occurred 2, 4 and 6 weeks later for each treatment combination.

Preliminary results indicate that soybean yield, regardless of planting date, was not impacted by fungicide or harvest aid treatment, but rather by harvest delay. As harvest was delayed beyond the appropriate harvest time, a yield decrease was observed. Preliminary results also suggest that harvest delay is linked to a decrease in seed quality as observed through germination tests. Future research should be conducted in order to fully determine the influence of management practices such as fungicide or harvest aid application on seed/grain quality following delayed harvest conditions.