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Effectiveness of Trees against Poultry House Emissions

by 5m Editor
5 October 2009, at 12:00a.m.

New legislation and growing populations in rural areas are driving the need to reduce environmental 'nuisances' like odours, dust and ammonia associated with raising birds through the greater use of vegetative buffers, says the Poultry Science Association.

Recent studies at Penn State University have demonstrated that the use of vegetative buffers – single or multiple rows of shrubs and trees – can significantly reduce odors, dust and other factors impacting the immediate environment around poultry farms, according to the Poultry Science Association (PSA).

Dr Paul Patterson, a professor at Penn State's Department of Poultry Science, has been a leader in the effort to quantify the degree to which different types of vegetative buffers can help address a number of 'nuisance' factors that are a natural part of the poultry grow-out process, while at the same time improving farm aesthetics.

Dr Patterson said: "Investing in foliage and landscaping around poultry farms can pay multiple environmental dividends to growers.

"Certainly, they can help beautify the landscape by providing a visual barrier for operations, so neighbours don't have to be constantly exposed to routine activities like feed deliveries and the loading and unloading of birds.

"But at least equally important, vegetative buffers can also help address a number of issues relating to poultry farm operations that nearby residents, particularly those new to the rural areas where poultry farms tend to be located, sometimes complain about – and which some state legislatures have begun demanding that growers address."


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"Vegetative buffers can be effective in reducing infectious bronchitis (IBV) transmission via wind, between birds on the same or different farms."
Dr Paul Patterson

PSA president, Dr Sally Noll said: "Professor Patterson's work has broken new ground in demonstrating the variety and effectiveness of vegetative buffers as tools to help meet some of the challenges now facing the poultry industry when producing poultry in more populated areas. The work can be readily adapted by industry as needed."

Foliage Reduces Dust by Two-Thirds

In research at a Penn State hen farm, Dr Patterson's team measured a 67 per cent reduction in total levels of particulate matter (PM) at a distance of 20 feet downwind from a five-row vegetative buffer, with important differences in the types of plant species used. Particulate matter at 2.5 microns and 10 microns (PM2.5 and PM10, respectively) are EPA regulated emissions.

The team observed differences in the species of foliage used, with willow capturing more of the fine PM2.5 and less of the intermediate sized PM10 than juniper vegetation. Associated research showed that spruce and hybrid willow are effective traps for dust and its associated odours.

Odour Reduced by 50 Per Cent

In Pennsylvania, in order to reduce the potential for community conflict, new and expanding poultry and livestock farms are required by the state to develop an odor management plan and submit to an odor site index. Scoring high values on the index require farmers to implement specific, and often costly, Best Management Practices (BMPs) specified by the state. According to PSA, studies by Dr Patterson's team have shown that appropriate use of vegetative buffers can help reduce odours and associated index scores.

In a September 2008 study, Dr Patterson's team measured a 46 to 54 per cent reduction in odour levels as a result of the use of a vegetative buffer comprising 50 fir, juniper, willow, ornamental pear and birch trees, when compared to odours without trees present. (The study used a pot-in-pot system that allowed placement and removal of the trees; the odour levels were determined using St. Croix Sensory's AC'SENT olfactormetry software.)

Reducing Ammonia and Some Forms of Virus Transmission

According to PSA, Dr Patterson has also demonstrated that vegetation can help trap ammonia emissions emanating from poultry houses. The amount of foliage needed to 'scrub' emissions will depend on the size and type of facilities. The vegetation used by Dr Patterson in his ammonia studies included honey locust, hybrid poplar vegetation, reed canary grass and Norway spruce.

Dr Patterson has also shown that vegetative buffers can be effective in reducing infectious bronchitis (IBV) transmission via wind, between birds on the same or different farms.

Other Uses of Vegetative Buffers

Dr Patterson added: "In addition to improving farm aesthetics and lowering dust, odour and ammonia levels, shrubs and trees can also help hold down energy costs.

"Strategically placed, these buffers can act as snow fences, dropping snow in front of the buildings instead of on the roof or around access roads, feed bins or fans. Other vegetation can be planted to shade the radiant load of summer sun on the buildings to cool the air entering the inlets or curtains.

"So investment in appropriately selected and sited vegetation around poultry farms really can yield a surprising number of benefits," he said.

Dr Patterson's work was funded by grants from the USDA National Resources Conservation Service and the Pennsylvania Department of Agriculture.

October 2009