Home Page
Newsletter
Topics
Webcasts
More...
All articles about:
Research Summaries
Manure Nutrients
Purpose
The purpose of this project is to improve phosphorus (P) cycling in livestock and crop-based managed ecosystems while reducing P delivery to surface waters. Methods will be developed to:
- remove P from distillers grains and corn gluten feed
- reduce the cost of transport for improved distribution of manure nutrients through alternative manure handling practices, such as composting;
- improve and target manure application practices to reduce risk of P runoff; and
- provide education to stakeholders on P related issues.
Current Activities
Experiments are underway for the removal of the degraded phytate phosphorous from beer bottom (BB) from the dry-milling and light steep water (LSW) from the wet-milling. Methodologies are being developed to degrade phytates.
Field work has been completed on: the effectiveness of setbacks to field application of manure; a comparison of composted vs. stockpiled manure; and on grass filter strips for reducing P runoff. Manuscripts are in preparation.
Watershed research using SWAT to target best management practices for reduced P in runoff continues. A decision tool, that considers N balance as well as costs and benefits, is being developed to aid beef cattle feeders in deciding if composting has value as a feedlot manure handling component.
Information concluded from completed research within the grant is used to educate producers and their advisors and attendees of various field days.
What We Have Learned
About 77 and 90% of the phytate phosphorous in the BB and LSW, respectively, were effectively degraded to phosphoric acid, suggesting an opportunity for significant P removal.
Setbacks were found to be ineffective in reducing runoff P while sediment loss may be increased with a 40 meter setback compared to no setback. Narrow and wide grass filter strips reduced runoff P by 52 and 78%, respectively, from sites with excessive surface soil P. One-time deep plowing reduced P runoff by 51% in cases of excessive surface soil P.
Total nitrogen recovery was 86 and 56 percent for stockpiled and composted feedlot manure, respectively. Based upon land application of composted and stockpiled manures under summer conditions, stockpiled manure will have greater nutrient value as compared to compost.
Why is This Important?
The economic benefit of feeding distillers grain makes this a very attractive feed product. However, this product adds significant additional P to a cattle feedlot. This work offers the potential for reducing P accumulation on feedlots and provides better alternatives for managing excess P from current and past feeding of distillers grains.
For More Information
Wortmann, C.S. and C.A. Shapiro. 2007. The effects of manure application on soil aggregation. J. Nutr. Cycling Agroecosystems. Published online: 21 Sep 2007.
Wortmann, C.S. and D.A. Walters. 2007. Residual effects of compost and plowing on phosphorus and sediment in runoff. J. Envir. Qual. 36:1521-1527.
Authors: Charles Wortmann <cwortmann2@unl.edu>, D. D Hutchens, and H. Noureddini, University of Nebraska
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.
