This study investigated the potential for nutrients from a headland-stacked poultry manure pile to move into groundwater at two sites. At one site with shallower groundwater, increased nitrate levels were detected after a large storm event, while no increase was found at the deeper site. The results suggest current regulations for siting manure piles are effective in preventing groundwater impacts, but unusually large storms could pose a risk, especially at locations with shallow groundwater.

1. Water Quality Impacts of Poultry Manure Headland Stacks Impact on Groundwater Study Paul T. Kivlin Dennis R. Frame Nutrient Management Specialist Director – Professor Nutrient and Pest Mgmt. Program UW - Discovery Farms University of Wisconsin – Extension

3. Goal of the study Investigate the potential for nutrients to move from headland stacked poultry manure into groundwater.

4. Study design Approximately one hundred tons of poultry litter (manure and bedding) were piled and shaped in a manner that resembled a “typical” headland stack and left in place for one year.

5. Study design To evaluate this objective, two sites that comply with the WDNR requirements for soil type, soil particle size distribution, and depth to groundwater were selected (RM and MM).

6. Study design Both study sites were located on Rosholt silt loam soils. It is also the most susceptible soil to leaching among those used for stacking.

7. Two sites in Barron County were chosen that represented the “risky” soil characteristics allowed by the WDNR for headland stack siting. MM Site: Rosholt soil 12 ft. to groundwater RM Site: Rosholt soil 24 ft. to groundwater Rosholt soil: 18 to 24 inches of silt loam leading to sand and gravel.

8. Study design and protocols The design for this groundwater monitoring study utilized an array of six well nests at each location

9. Study design and protocols Monitoring Well Nest Well Placement (one shallow well, one deep well) Well Nest Soil surface Manure Pile 100 ft Groundwater level 10 ft Groundwater flow direction

10. Study design and protocols The manure stack was positioned perpendicular to the direction of groundwater flow (determined by drilling additional water table wells).

11. Study design and protocols The three nests “up gradient” of the manure pile represent water samples not influenced by the stack, while the three nests “down gradient” represent wells that may be influenced by the headland stack.

12. Study design and protocols Wells were sampled weekly for three weeks before the manure was put in place. Wells were sampled monthly for one year after the stack was removed, then quarterly for another year (two years total).

13. Constituents Tested: Nitrate / Nitrite Chloride Conductivity Total Dissolved Solids Total Kjeldahl Nitrogen Ammonium Organic Nitrogen pH

15. The manure stack was in place for one year. Wells were sampled monthly for three years.

16. Included a 10.5 inch storm 25 yr/24 hr storm = 4.6 inches 100 yr/24 hr storm = 5.8 inches 25% of ’07 precip.

17. Averages: Beginning 10/04 = 8.6 ppm Ending 12/07 = 5.9 ppm Averages: Beginning 10/04 = 12.9 ppm Ending 12/07 = 18.7 ppm

18. Included a 4.2 inch storm

19. Averages: Beginning 10/04 = 13.9 ppm Ending 12/07 = 15.9 ppm Averages: Beginning 10/04 = 13.3 ppm Ending 12/07 = 14.7 ppm

20. Conclusions: The poultry manure stack caused increased nitrate levels at the MM site. This site received an atypical 10.5 inch / 24 hour storm event.

21. Conclusions: The poultry manure stack did not appear to cause increased nitrate levels at the RM site. This site received a 4.2 inch / 24 hour storm event.

22. Conclusions: Current design specs for a 25 year /24 hour event (4.6 inch event) appear to be effective.

23. Conclusions: The difference in results between the sites seems to be attributable to the abnormally large, 10.5 inch storm event. Other factors could include: depth to groundwater, soil profile variations, or groundwater flow rates (MM – 0.72 ft/day, RM – 1.53 ft/day), etc.

24. Information Available Briefs / Articles –summarization of factsheets Factsheets - six page factsheets that provide much of the information and data gathered through each phase of the study. Presentations – this is the fifth in a five part series on headland stacking of poultry manure

25. For Additional Information http://www.uwdiscoveryfarms.org/ UW Discovery Farms 40195 Winsand Drive PO Box 429 Pigeon Falls, WI 54760 1-715-983-5668 jgoplin@wisc.eduor drframe@wisc.edu