The study investigated the potential for nutrients in headland stacked poultry manure to impact surface or groundwater quality. Researchers found that the nutrient content of different types of poultry manure were generally consistent, allowing the use of average nutrient values. Poultry manure was also found to have excellent water holding capacity, absorbing about 37% of its weight in water. Infiltration tests found water moved through stacked poultry litter at a rate of 11.46 seconds per inch under extreme pressure conditions, though actual field conditions would result in a slower rate. Overall, the study concluded headland stacking of poultry manure has very limited potential to pollute surface or groundwater due to the material's ability

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

2. Goal of the study Investigate the potential for nutrients to move from headland stacked poultry manure into waters of the state (surface or groundwater).

3. Headland Stacks Headland stacks are manure piles stored on bare soil at the edge of crop fields until the field is ready for application. Stacks are normally applied to fields within three months, but may remain in place for up to one year.

4. Stacking Pad

5. Study design To better understand the potential water quality challenges from headland stacks of poultry manure, the study was divided into three phases: Nutrient content variations in different turkey manure “types” Headland stacking effects on surface water Headland stacking effects on groundwater

6. Study parameters Nutrient concentrations Percent dry matter Water holding capacity Infiltration rate

7. Nutrient content variations Nutrient content and variations in different turkey manure “types”. Breeder First skim, second skim, third skim Total cleanout Pad 600 manure sample analysis reports were reviewed.

8. Nutrient content variations Several years of manure analysis data was compiled and evaluated. Averages were compared to WI book values to determine if they adequately estimate the nutrient availability for turkey manure.

9. Manure nutrient content variations 600 manure analysis reports were reviewed. Variations in the nutrient content of different manure types (1st skim, 2nd skim, 3rd skim, total cleanout, breeder barn, brooder barn, stacking pad) were not significant.

10. Nutrient content variations In general, poultry manure is much more consistent in terms of nutrient concentrations than other species of livestock manure. With few exceptions, most of the analyses of nutrient concentrations for turkey manure were very similar.

11. Manure nutrient content variations A single N-P-K analysis could be used. Turkey manure 1st yr. avail. (N-P-K): 30-25-25(inc.) 38% moisture Solid dairy manure 1st yr. avail. (N-P-K): 4-3-7(inc.)

12. Nutrient content variations Producers and agency personnel that pay close attention to application rates and timing can feel confident that book value nutrient credits are correct.

13. Nutrient content variations In reviewing the 600 manure samples, season had little effect on nutrient content of manure. Diet, bedding characteristics, and type of birds played a larger role in varying manure nutrient concentrations.

14. Water holding capacity

15. Water holding capacity This part of the study evaluated the ability of poultry manure to absorb and hold water. The manure chosen for this experiment had been stacked on an impervious asphalt pad for a minimum of six months.

16. Water holding capacity Pad manure was chosen for the water holding capacity and infiltration rate exercise because of its advanced decomposition which would minimize the water holding capacity and therefore, represents the lowest capacity of all forms.

17. Water holding capacity Water holding capacity was calculated by passing water through a series of four inch wide PVC columns packed with poultry litter.

18. Water holding capacity Four feet of poultry manure was placed on top of the filter system. Six liters of water were forced through the columns, while maintaining one foot of head pressure.

19. Water holding capacity The columns were left until all water had dripped from each column. To determine the water holding capacity, the manure was weighed before and after saturation.

20. Water holding capacity Manure saturation was verified visually and by adding additional water to the column. Column 4 had an additional 1,000 milliliters (ml) of water added to the system, and virtually all the additional water passed through the collection container

21. Water holding capacity

22. Water holding capacity Based on these results, poultry manure has excellent water holding capacity. One pound of dry poultry manure can hold approximately 230 ml of water. Estimated that a ton of dry poultry manure can hold approximately 730 pounds of water.

23. Rate of infiltration

24. Water infiltration rate The final objective was to determine the infiltration rate of water running through a stack. How fast water moves through is important in determining the potential for nutrients to leach through a stack on bare soil.

25. Water infiltration rate Water flowed through the manure columns at an average rate of 11.46 seconds per inch of manure. One must take into consideration that in order to achieve these flow rates, one foot of head pressure was maintained.

26. Water infiltration rate This type of pressure would not exist under field conditions. It would take approximately a 36 inch rainfall event to provide the amount of “rain equivalent water” as was used in this study.

28. Conclusions for Phase 1 Poultry manure has much less variation in nutrient concentration than most other types of livestock manure and appears to be more predictable than either dairy or swine manure.

29. Conclusions for Phase 1 Season has little effect on nutrient content for manure coming out of poultry barns.

30. Conclusions for Phase 1 Poultry manure holds tremendous amounts of water. Based on the data collected, poultry manure can hold 37% of its weight as water. Therefore, most rainfall events would be absorbed by a headland stack and not run off the pile.

31. Conclusions for Phase 1 Infiltration of water into dry poultry litter is moderately rapid. The rate under extreme conditions averaged 11.46 seconds/ inch. However, these conditions are not likely under field conditions, so the infiltration rate into a headland stack should be much less.

32. Conclusions for Phase 1 The tendency for poultry litter with similar levels of dry matter and organic matter to hold large amounts of water suggests that headland stacking of this material has very limited surface water and groundwater pollution potential.

33. 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 second in a five part series on headland stacking of poultry manure

34. 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.edu or drframe@wisc.edu