Deer damage has become a national, natural hazard to crop producers. It has been estimated that a total of $100 million loss on agricultural crops is caused by deer annually in the United States (wvdnr.gov). Ober, et al. in 2014 reported that 9.6% of soybean acreage in North Florida was damaged by deer, causing estimated value of $1,458,959 loss. Mid-Atlantic farmers also complain about deer damage. Some fields cannot be used to grow soybean anymore because of recurring extensive deer damage.
Many states in the United States have published deer management programs on their government websites, and extension specialists at some universities have studied and suggested deer damage control strategies. Hunting, fencing and repellent are the three main management strategies; using the combination of two or more methods may be the most efficient to reduce deer damage. However, all of those strategies need investment of materials, labor and farmers’ time. The use of a biological fence with traits that appeal to deer is considered the most cost-effective solution to reduce deer damage on crops.
One example of this strategy is the soybean research field at Kentland Farm, VA. It has been protected by a soybean fence for the past two years. We observed that deer feed on these fencing plants, but no scientific study has been conducted to quantify the efficacy of the strategy. Our hypothesis is that deer-appealing soybean varieties should include, new growth, higher sugar, and exceptional biomass with transgenic traits for transgenic soybean fields. Once the hypothesis is confirmed, we will develop a producer-friendly protocol that employs protective rows around soybean fields such as number of rows. Our deer-appealing varieties should be the best solution to reduce deer damage with easy implementation and a low cost. It is expected that these varieties will benefit all soybean growers in the Mid-Atlantic area because the fencing is being employed simply as deer-food rows, so a particular maturity and yield are not as important.
“Soybean is the most popular item on a deer’s menu” - Deer readily and preferentially forage on soybeans because they can feed on plants showing the fourth trifoliate leaves until the late reproductive stages. For several months, soybean leaves and young stems are easy to digest, and soybean is an excellent source of protein (Loos, 2013). Maryland farmers suffered more than $7 million from deer damage in 2013 (wideopenspace.com), and this economic loss has not been reduced. 2016 was a drought or semi-drought year for many counties in Maryland, so the crop profit margin was tight, causing farmers’ less tolerance to deer damage. Joel Steinman in northern Dauphin County near Halifax estimated $20,000 loss by deer (ourdoornews.com). In order to reduce the crop damage, some farmers either become hunters themselves or become big fans of deer hunters (Blanton, 2007; Loos, 2013). Complications from hunting are apparent. For example, Glenn Miller, another farmer from northern Dauphin County who farms 1,000 acres, didn’t want to shoot deer eating soybeans in the middle of his soybean field because dragging dead deer out would cause even more damage (ourdoornews.com).
Hunting is not the only way to regulate deer - Hunting may be the most feasible and economic way to keep the deer population stable, but other control methods are also necessary to manage deer damage. Two popular ways to reduce deer damage are fencing and repellent. A single strand of electric fencing at 2 feet tall deer’s fear of electric shock or odor to reduce their access to fenced field, and an electric fence can be solar powered (Woods, 2015). However, deer often become adapted to the fence and develop fence tolerance, so crop damage continues (Dixon, 2002). Repellents have also been used to reduce deer browsing, but these have to be reapplied after rain (Pierce and Wiggers, 1997). Using integrated damage management, one or more methods together, may be the best way to control the damage. Thus, farmers need to learn management techniques such as fence installation and maintenance as well as incur the associated costs of damage control on their own fields.
Deer appealing vs. unappealing soybean varieties - There is no any published information about soybean varieties preferred by deer, but deer do choose varieties to browse according to breeders and growers’ field observation. For example; we grew two soybean varieties as a fence at the crossing block at Moore farm, Blacksburg Virginia in 2015. One variety was badly damaged by deer, but the other one was rarely touched. Deer also have their own paths to eat in the field. Bryan Taliaferro, Virginia soybean grower, claimed that deer browsed on one section of his field where the same variety that was browsed at the Moore Farm was grown. Acorn is also a favorite food of deer. Deer prefer white oak acorn more than red oak acorn because white oak acorn is less bitter than red ones (gundata.org). Therefore, soybeans with appealing leaf compounds might divert deer’s attention. Deer often show a preference for natural and agronomic forage type soybeans, hence we assume that continually growing, large leaf, and higher sugar content of soybean varieties would be browsed heavily, but we haven’t tested the sugar content in soybean leaves because we only test sugar content in seeds.