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Research Summaries

Research Purpose

The objective of this research is to evaluate the bio-physical, economic and social efficacy of the use of Vegetative Environmental Buffers (VEBs) - purposefully planted linear arrangements of trees and shrubs - to incrementally mitigate livestock and poultry odor. Our research has demonstrated that tree barriers can help impede, alter, absorb, and/or dissipate livestock odor plumes and other emissions prior to contact with people. As air moves across vegetative surfaces, leaves and other aerial plant surfaces remove some of the dust, gas, and microbial constituents of airstreams. Trees and other woody vegetation also enhance localized air dispersion by increasing mechanical turbulence. Our research program into the efficacy of VEBs involves a multi-disciplinary, multi-species and multi-analytic perspective.

Activities

The efficacy of VEBs in mitigating livestock and poultry odor is being examined from a three- pronged perspective measuring efficacy in:

1. field measured bio-physical terms (e.g. physical reductions in downwind movement of particulates, odor and ammonia and long-term tree health)
2. financial feasibility terms at the farm-level (e.g. total costs of VEB establishment and maintenance vs. producer willingness to pay), and
3. in terms of social approval of the use of VEBs (e.g. evaluation of the impact of VEBs on production site aesthetics and consumer willingness to pay for environmentally friendly meat products).

The quantification of physical odor mitigation via the use of VEBs is approached with field trials using full size VEB systems (multiple rows of trees) at working poultry and swine facilities as well as using scale models of these facilities for wind tunnel examinations and advanced computer simulation.

Custom rate financial data has been collected and applied to a range of livestock facilities (e.g. differing VEB designs, production scale, etc.) to calculate typical upfront and long-term costs. Producer willingness to pay has been determined via multi-state producer surveys. Social opinion data was collected via multi-state consumer focus groups (utilizing photo elicitation techniques) and a series of integrated social surveys.

What We Have Learned

Baseline physical data suggests that VEBs can contribute up to a 10% reduction in the movement of odor downwind. The technology broadly applied at the farm level seems to be financially feasible to most swine producers – with total costs ranging from $0.01 to $0.33 per pig produced; these costs by and large being well below maximum producer willingness to pay for the use of VEBs. And social surveys in IA and NC show strong social support and appreciation of the use of trees for air quality purposes with strong social agreement that VEBs improve the aesthetics of confinement production.

Why is This Important?

Affordable, tertiary odor mitigation technology with the added benefit of being socially acceptable is a strong compliment to any comprehensive manure management program at production sites .

For More Information

Author: John Tyndall, Iowa State University

Visit the Iowa State University vegetative environmental buffers website.

Read the following article: Tyndall, J.C. and J.P. Colletti. 2007. Mitigating Swine Odor with Strategically Designed Shelterbelt Systems: A Review. Agroforestry Systems. Volume 69, Number 1/January, 2007.

This report was prepared for the 2008 annual meeting of the regional research committee, S-1032 "Animal Manure and Waste Utilization, Treatment and Nuisance Avoidance for a Sustainable Agriculture". This report is not peer-reviewed and the author has sole responsibility for the content.