1. Water Quality Impacts of Poultry Manure Headland Stacks Surface Water 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 surface water.
3. Goal of the study Evaluate the potential for nutrients (nitrogen and phosphorus) to run off a headland stack of poultry manure and enter surface waters.
4. Goal of the study Evaluate why crops do not grow for a period of time after removing a pile of manure. This objective was studied in this phase of the project, but the information is provided in a separate presentation.
5. Study design To evaluate these objectives, a site that met WDNR requirements regarding soil type, slope, soil test levels and location for headland stacked poultry manure was selected.
6. Surface water study Phase One provided valuable insights on how much rainfall could be absorbed by a headland stack. Hypothesized that a typical stack of poultry manure would absorb most of the rain that fell on it during the crop season.
7. Surface water study Hypothesized that the greatest potential for runoff would occur under extreme rainfall conditions (25 year, 24 hour storm events), where portions of the stack become saturated.
8. Surface water study Hypothesized that the greatest risk for runoff events were from those portions of the stack with minimal manure depth (at the edges of the pile).
9. Potential surface water impact Headland stacking effects on surface water. Using “pad manure”, the water holding capacity of turkey manure is about 40% by weight.
10. Potential surface water impact Headland stacking effects on surface water. Measure manure stack runoff for one year from a site that is approved by the DNR.
20. Explanations for lack of runoff Poultry manure has an extremely high water holding capacity. Visual observations of the manure stack during intense rainfall events also revealed that the water appeared to absorb into, and not shed from, the stack itself.
21. Explanations for lack of runoff Moisture levels in the manure pile indicate that the moisture was highest close to the surface of the stack and becomes drier deeper into the pile.
22.
23. Explanations for lack of runoff The reason for lower moisture content within the center and bottom of the headland stack is that substantial heat is generated within the pile because of composting.
24. Explanations for lack of runoff The heat generation evaporates moisture from the pile and, to some degree, offsets moisture added during rainfall events.
25. Vegetation around stack A thick mat of vegetation, primarily common lambsquarter, redroot pigweed, giant ragweed, and giant foxtail grew around the edge of the pile.
26. Vegetation around stack This vegetation further facilitated the infiltration of rain into the soil immediately surrounding the manure stack and decreased the possibility of runoff leaving the site.
28. Results of soil sampling Soil samples were taken prior to stacking. Soil samples were taken immediately after stack was removed. Samples were taken in the center and on the edge of the stack.
30. Results of soil sampling Soil analyzed from underneath the direct center of the stack detected relatively high levels of ammonium.
31. Results of soil sampling Soil analyzed from underneath the direct center of the stack detected lower levels of nitrate.
32. Results of soil sampling Phosphorus movement into the top foot of the soil was apparent.
33.
34.
35.
36. 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
