Study highlights extent of crop damage by deer Unique research into the damage caused by wild deer in high value root crops has shone a light on potential crop losses affecting growers in eastern England. Dominic Kilburn writes. Slugs, rabbits, flea beetle, viruscarrying aphids and potato cyst nematodes are, as well as many others, some of the key pests which arable farmers have to deal with each season in order to protect their crops from significant yield losses. Add to these some extremes of weather, poor establishment, a delayed harvest, a never-ending battle against black-grass and other grass and broad-leaved weeds, and you begin to see why farm margins are constantly under pressure and in need of protection. One threat which often seems to fall under the radar in agricultural pest control discussions is that of wild deer and the potential impact some of the six species found in the UK can have on crop yields. Perhaps this is because actual crop damage affects relatively few growers, while calculating the scale of yield loss from a resident or passing herd of fallow deer, for example, is simply too hard to fathom. Or maybe it’s because most wild deer are seen by many landowners as a thing of beauty and, rightly or wrongly in terms of farm margins, they are happy to see them run freely on their fields or reside in their woodland.
Sustainable management The perception following research in the early 1990s was that the country’s woodland was under significant threat from an expanding national deer herd. And so, to counter this, The Deer Initiative was established by the Forestry Commission in 1995 to specifically focus on woodland protection. The aim was to bring people and organisations together to plan for effective and sustainable management of wild deer in England and Wales. However, tackling deer-related vehicle collisions, reducing their impact on vulnerable habitats and supporting deer management under Environmental Stewardship and the
Woodland Grant Scheme, have also remained part of The Deer Initiative’s remit ever since. Deer impact specifically to agricultural crops is an area that has received little attention (or research) in the past 20 years, acknowledges the Initiative’s East of England liaison officer, David Hooton. “Crop losses to deer are generally considered as not being significant in the majority of areas but, where large numbers of fallow or red deer are present, impacts can be significant and often these areas are found on, or adjacent to, areas of non-management – where no deer control occurs, often where a landowner is happy to have deer present. “Past research has indicted that yield losses in cereals can be as much as 10 per cent and, more recently, a number of growers have reported losses totalling £100,000. However the idea is that if woodlands can be successfully managed where deer populations are concerned, then agricultural fields in the proximity will remain relatively undamaged too,” he adds. Most woodlands in the east of England are under pressure from deer numbers (from a number of species), suggests Mr Hooton, but large grazing herds of fallow and red deer are the primary culprits for crop damage across the arable landscape. “In north east Norfolk, for example, growers have, in the past, reported high yield losses in salad crops and peas, while some malting barley was rejected this summer due to contamination by deer faeces. “They also graze on winter cereals which itself isn’t so much of an issue during the winter months, but trampling during wet conditions can become a problem. “Where they graze oilseed rape the crop can be stunted and therefore flowers late, delaying pod emergence and yielding lower. “Pasture can also be affected,” he adds.
Deer tracking damage to winter wheat.
Landscape management is key, stresses Mr Hooton, who works closely with The Deer Initiative member organisations such as the NFU and CLA, as well as with individual landowners. “We advise on all aspects of sustainable deer management including protection of woodland, tree and hedgerow biodiversity, but it’s also important for landowners to think about cropping patterns too,” he points out. “We are seeing a changing landscape in the east with the expansion of crops such as maize grown for AD plants, as well as an acreage of miscanthus, and they are providing additional habit for deer. “They spend a lot of their time in these types of crops, sheltering and feeding,” points out Mr Hooton. He says that while it’s very hard to put an accurate figure on the overall deer population in the region, estimates suggest that numbers have
stabilised. Effective management of deer in a specific place will either remove deer altogether or keep numbers at a sustainable level, he highlights, but it also means they might be moved on to another location and interact with other large herds – an area The Deer Initiative is looking to investigate further.
Unique study Angus Hill is in his third year of a BSc degree in Geography at the University of East Anglia and part-way through a dissertation on the extent of fallow deer impact on lowland farming in his home county of Suffolk. Angus has based his extensive research on three neighbouring farming estates in the coastal region of the county where high value root crops including potatoes, carrots and onions are prominent in rotations. Interestingly, the mainly arable continued over...
Deer damage – key species Fallow – Large herds may be the result of high deer densities, continual disturbance, animals gathering on a food source or prolonged hard weather. The most significant impact is caused by grazing and browsing (in fields and woodland). In woodland grazing/browsing may adversely affect regeneration and damage commercial tree plantings. Also well known for making tracks through, and sitting in, standing cereal crops, which can open crops out to wind-blow. Red – At high densities red deer can be very damaging to habitats and crops. Red deer may cover very large distances in their daily or seasonal movements and co-operative management across boundaries is the best way to manage them. Primarily grazers, they often use open areas to graze but will spend long periods browsing in woodlands. They will also lay up in cereal crops. Source: The Deer Initiative
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