Extension Communications
3614 Administrative Services Building
Ames, Iowa 50011-3614
(515) 294-9915
12/26/00
- Contacts:
Jeff Lorimor, Agriculture and Biosystems Engineering, (515) 294-9806, jclorimo@iastate.edu - John Lawrence, Iowa Beef Center, (515) 294-6290, jdlaw@iastate.edu
- Wendy Miller, Iowa Beef Center, (515) 294-9124, wmiller@iastate.edu
Feedlot Runoff Target of New Iowa-Based Study
AMES, Iowa -- In the early 1970s, Americans made huge strides toward protecting the quality of the nation's water supply. Scientists began to study the impacts of animal feedlot runoff on the surrounding environment, and EPA's Clean Water Act was implemented.
Today, the United States is still acutely aware of water quality issues. Farmers who raise livestock are taking more care than ever to be responsible stewards of the land. However, much of the information on open lots available today is that same research material garnered nearly 30 years ago.
The Iowa Beef Center at Iowa State University recently designated a one-year grant to again study the impacts of cattle feedlot runoff in a modern setting.
"Not only are feed rations completely different today, but cattle genetics are vastly improved over what they were 30 years ago," said Jeff Lorimor an assistant professor in the ISU Agriculture and Biosystems Engineering Department who will head up the new study. "This project is aimed at determining the nutrients in the solids coming off of Iowa feedlots rather than specifically focusing on liquids as in prior studies."
John Lawrence, director of the Iowa Beef Center, said Lorimor's study was the unanimous choice for the grant. "This study will help Iowa producers better understand the nutrient values of the manure in their lots. With this information in hand, they can decide how to best use these nutrients on agricultural lands and develop effective nutrient management plans."
Feedlot solids come from two main sources: scrapings and settling basins. Feeders who house animals in concrete lots normally scrape the lots clean once a week; those with earthen lots may only scrape annually. Therefore, nutrient concentrations will vary considerably depending upon facility type and scraping frequency.
Settling basins are required by federal law. By slowing the runoff, basins allow solids to settle and effluent to travel into a filtering system. Producers must clear basins regularly to keep them working properly, and then disperse the manure solids on cropland.
"By studying the nutrient concentrations in solid manure, we can help producers determine the best application rates for crop ground," Lorimor said. "This can improve Iowa's water quality in two ways. One, it has the potential to keep producers from over-applying manure and two, by learning appropriate rates we can replace some commercial fertilizers with manure-only applications."
In addition to ISU research facilities, five to six privately owned feedlots statewide, both concrete and earthen, will be studied. ISU Extension field specialists will work with selected producers to measure volumes and collect samples each time a lot or settling basin is cleaned.
"Iowa producers simply cannot make informed decisions about nutrient management without modern data," Lawrence said. "We hope this study will help make Iowa one of the premier states in both cattle feeding and water quality."
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