Air Quality and Shelterbelts

by 5m Editor
28 August 2006, at 12:00am

By John Tyndall and Joe Colletti, Forestry Department, Iowa State University - This literature review is focused on the potential for innovative use of trees and other vegetation to reduce the odor associated with livestock production.

The goal is to examine available evidence to assess if trees and shelterbelts may: 1) be able to help control odor through physical and biological means, and 2) be an economically feasible technology for livestock producers as well as surrounding communities.

The current stage in the evolution of livestock agriculture in the United States is toward increased industrialization and involves the infusion of multiple technologies, the concentration of production and processing facilities and the integration of inputs to production, processing, and marketing. This evolution is most easily identified by changes in the overall size of the facilities and in increases in the average number of animals per farm system. The increases in size is primarily due to perceptions that large operations benefit from economies of scale, particularly in terms of expenditures for labor, feed, and facilities, which have caused producers to try to capture those potential benefits (SOTF, 1995).

In terms of overall animal production in the U.S., the total number of animal units per farm operation increased considerably. For example, from 1978-1992 the average number of animal units per U.S. cattle operation increased by 56%, dairy by 93%, hogs by 134%, and layer poultry 176% (US EPA, 1999). However, during this same time period the overall number of livestock operations decreased considerably as well.

The number of cattle operations dropped by over 40%; dairy, hogs, and layer poultry by over 50% (US EPA, 1999). All of this indicating significant consolidation within the industries and greater production from fewer, larger production facilities, which are based on animal confinement systems

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March 2000