Primarily, two treatments will be conducted: no fence in a traditional RR soybean grown for grain as positive control, and a "biological fence" using forage type soybean with RR trait that could be used for RR soybean growers. Three replications of each treatment will be applied on each field. The RR soybean for grain will be harvested when mature. The yield of each plot will be recorded to compare the effect of biological fence. Our hypothesis for objective 1 is that plot yield with biological fencing is significantly higher than the plots without fencing. Our hypothesis for objective 2 is that concentrations of sucrose, glucose, and/or fructose will be higher in the foliage of forage soybeans compared to soybeans grown primarily for grain.

Updated November 23, 2020:

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Forage soybean yield on farms - Complete crop loss of the forage soybean due to deer overgrazing was observed on several of the fields in 2019. Project PI’s were disappointed with results in reducing deer damage in 2019 compared to 2018. Because we felt that we did not have enough deer pressure in 2018, we intentionally put the trials in areas of known high deer populations, leading to grazing of the forage soybeans at or near emergence, inhibiting the plant’s ability to establish itself. This is demonstrated in Figure 1, showing the extremely low yields in the areas of this field near treeline border. A possible factor in the difference between 2018 and 2019 is that all of the trials in 2019 were planted earlier then in 2018.

Because of the disappointing results in 2019, investigators at University of Delaware are conducting a demonstration project on double crop beans using deer repellant to provide the forage soybeans a chance to emerge and establish themselves prior to heavy grazing by deer. It may have been beneficial to apply deer repellent on sprayed our forage beans with deer repellant to buy them time.

Variety Yield, bu ac-1 (mean ± standard error)
73P93R 34 ± 3 a
7447XTS 26 ± 3 bc
AG48X9 31 ± 4 ab
BigFellow 14 ± 2 d
S53-F7X 25 ± 3 c
V12-4590 17 ± 1 d

Soybean yield at Beltsville REC – Six varieties, including one forage soybean variety (BigFellow) were evaluated for yield and sugar content in 2019. Yield measurements below demonstrate the low yield observed in the BigFellow forage soybean variety compared to the rest of the agricultural soybean varieties. The BigFellow performed similarly to V12-4590 variety, however this variety was planted extremely late and its yield potential was likely limited due to this.

Foliar sugar content – Compared to last year, the foliar sugar content data was not as straightforward. The forage soybean did not have increased total sugar content at any sampling time period compared to agricultural soybeans, nor did it have increased content of the different sugar forms (fructose, glucose, or sucrose). The V12-4590 variety that was planted quite late had higher fructose concentration at the third sampling time period than any other variety evaluated. Further research should identify which sugar type is most attractive to deer and if a later planting date might increase that sugar content enough to divert deer from commodity soybeans.