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STAR Grant R833423: Effects of Cattle Manure Handling and Management Strategies on Fate and Transport of Hormones in the Feedlot and the Field 2007 - 2010

Project Purpose:
This study aims to determine the occurrence, fate, and transport of natural (endogenous) and synthetic (exogenous) hormones at four CAFOs during the application of cattle manure to crops and conservation buffers.

Project Description(s):

The proposed research focuses on the occurrence, fate and transport of exogenous and endogenous hormones during management of cattle manure produced at four concentrated animal feeding operations through its application to crop land and conservation buffers. The objectives of this research project are to (1) quantify hormones in various stages of the manure pathway in cattle feedlots, (2) determine the effects of different handling practices of cattle feedlot wastes on the stability and availability of hormones, (3) determine the effects of different land application strategies on the fate and transport of hormones used in beef cattle production, and (4) determine if grasses from conservation buffers assimilate hormones. The central hypothesis is that hormones in cattle manure will persist and accumulate in soil, but the fate and transport of hormones will be affected by the waste management and handling strategies utilized.

Five research tasks will address the objectives of this study. These tasks are: (1) to sample and survey four existing feedlots in Nebraska to determine the occurrence of hormones in the manure handling pathway over a climatic gradient; (2) to quantify fate of hormones as influenced by manure handling practices such as stockpiling, composting, and runoff retention basins; (3) to determine the effect of manure application strategies on hormone losses in runoff and erosion through the use of rainfall simulators; (4) to quantify hormones in select grass species in buffer strips fertilized by manure; and (5) to determine hormone fate and transport within irrigated soil systems.

Project Outcomes:
It is expected that endogenous and exogenous hormones and their transformation products will occur in cattle manure, will remain for extended periods of time in soil receiving cattle manure, and will under certain conditions be found in runoff from feedlots and fertilized soil. Specific management strategies such as composting will likely increase the degradation rate of hormones compared to stockpiling and help to minimize impacts to the environment. Analysis of soil leachate collected in lysimeters beneath irrigated crops will demonstrate if some vertical movement can occur in soils. Measurement of hormones in grasses growing in buffer strips fertilized with manure will indicate whether plant uptake of hormones can occur. The results of the project will serve as a research base to enable the scientific and regulatory communities to better understand how waste management practices influence the fate of hormones introduced into the environment from animal manures. The data from this project will provide valuable information to both regulators and farm operators to promote and balance agricultural production and environmental protection.

More Information
NCER STAR Grant site: Effects of Cattle Manure Handling and Management Strategies on Fate and Transport of Hormones in the Feedlot and the Field

Susan Laessig at laessig.susan@epa.gov

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