Strickland says deer represent an $860 million annual economic engine for Mississippi — hunting licenses, equipment, hunting leases, etc.

The Mississippi study, he says, is designed to estimate where in fields deer damage is occurring and how it changes over time.

“Soybean field size is a factor. If a field is large enough, deer damage is spread over more acres and is proportionally less than for a small field.

“Another consideration is, how many mouths are you feeding? In past studies of deer damage to soybeans, one thing that was never quantified is how many deer are causing the damage at the field level? They’ve tried to estimate populations from helicopter surveys, photo surveys, spotlight surveys, etc., but they were estimating the population over thousands of acres.

“We want to quantify the relationship between soybean damage and the number of deer eating beans in a particular field. Secondarily, we want to determine how the number of deer relate to the size of the field, how far into the field damage occurs, how much damage occurs at various spots, the impact of surrounding landscape characteristics, and whether we can use NDVI (normalized difference vegetation index) satellite imagery to help us make decisions rather than having to go out and make visual observations.”

What’s unique about this project, Strickland says, is that “We’re actually counting the number of deer browsing in each field, using infrared devices that detect the deer heat signature. Student technicians sit in the study fields from sundown until midnight, continually sweeping the fields with the infrared devices and counting the number of deer. The deer stand out like a sore thumb. It’s also easy to distinguish the difference between deer and feral pigs, which also cause significant soybean damage in many areas of the state — a pig never lifts its head up.”

The study also is examining how deer impact varies from the field border to the middle of the field. “We do this by establishing protected areas all the way from the edge of the field to the center, then comparing those with the unprotected areas, and correlating those data with how browsing levels vary through the field. We’re also looking at the impact of surrounding habitat on damage within the field.

“We’re measuring plant height, growth stage, and browse counts — number of plants, number browsed/not browsed, number of leaves, and other information. We’re doing this every week in early season and every two weeks later in the season. We also collect plant matter during the season and yield data at the end of the season. All this involves thousands of data points, and a tremendous amount of data to analyze.”

If deer eat small soybean plants, they usually don’t recover and that yield potential is lost, Strickland notes. In other cases, deer just crop the top of the plants. Even late in the growing season, deer damage to soybean plants was still being seen.

Research in Maryland, he says, showed that in a few situations, deer browsing actually improved soybean yields. “They were cropping just enough off the plants to cause more branching, in turn resulting in more beans produced. But I don’t think many farmers would want to count on that happening.”

Some pilot work is also being done on the effectiveness of Hinder repellent, he says, including the number of applications required for different deer densities.

“Sometimes repellents are effective, sometimes not — again it depends on the number of deer and field size.”

Depredation permits are another option for deer control, Strickland says. ‘In some cases, this is absolutely warranted; in other cases, it may not be worth it. It depends on the extent of the damage.”

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