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PRESENTER NOTES
Discussion Question:
1.What are the five pathways by which manure contaminants can reach water?
Key Discussion Topics
1.Runoff.  Runoff from open lots, land application sites, and manure and feed storage represents a common pathway for contaminant transport.  All contaminants in manure will travel with surface water runoff and soil erosion.  Problems associated with phosphorus, pathogens, ammonia, and organic matter are most commonly associated with runoff or erosion.
2. Leaching.  Dissolved contaminants such as nitrate nitrogen will leach through the soil when the soil moisture exceeds its water holding capacity.  Most contaminants in manure and other byproducts (e.g., organic matter, pathogens, and typically phosphorus) are filtered by soil and will NOT leach to groundwater.  Soil structure, chemical reactions with soil minerals, and negatively charged soil particles typically restricts the movement of many contaminants.  However, soluble contaminants such as nitrate-nitrogen, may move beyond a crop’s root zone and contaminate ground water.
3. Movement down a well casing:  Wells located in close proximity to a manure storage or outdoor lot can be at risk to nutrient and pathogen contamination.
4. Ammonia Volatilization and Deposition.  Ammonia-nitrogen volatizes from manure storages, lagoons, and open lots.  Once volatilized, most ammonia is re-deposited with rainfall or through dry deposition.  It can be transported over long distances.  Many areas of the world profit from this nutrient deposition.  However, some areas of the world are experiencing high enough deposition that threatens vitality and growth in local ecosystems.  In the United States, coastal areas are often adversely affected by ammonia deposition.  Nitrogen availability rather than phosphorus typically limit eutrophication in coastal waters.
5. Macropore Flow.  Most contaminants in manure can travel through soil to shallow groundwater tables or tile drains. Macropore pathways (root holes, wormholes, cracks due to soil drying) can provide pathways for contaminant movement that bypasses the filtering capability of soils.
Discussion Question:
References
LPES Lesson 1:  pages 16-17
PRESENTER NOTES
Key Discussion Topics
1. Ammonia volatilization and deposition provides an additional pathway by which ammonia can move to surface water.
2. In addition, all contaminants can be transported with runoff down poorly designed well casings and through the soil by macropore flow to shallow ground water or tile drains.
Discussion Question:
References
LPES Lesson 32:  pages 3-4.
PRESENTER NOTES
Key Discussion Topics
1. Manures contribution to improved soil structure results in improved water infiltration and greater water-holding capacity, benefiting crop water stress, soil erosion. 
2. An extensive review of the literature and historical soil conservation experiment station data (Risse and Gilley, 2000) at selected locations around the U.S. suggested that manure produced substantial reductions in soil erosion (13%-77%) and runoff (1%-68%).
3.  Increased manure application rate produced greater reductions in soil erosion and runoff. 
4. A residual benefit of past manure application was noted during years when manure was not applied.
Discussion Question:
References
LPES Lesson 1:  pages 9-10
PRESENTER NOTES
Broadcasting manure is faster than injecting.  Incorporation after manure is broadcast helps, but does not eliminate or reduce odors as well as injection.
PRESENTER NOTES
One way to minimize odor during the spray irrigation of manure is to dilute it considerably with fresh water.  The thicker it is the more concentrated the odors will be.
PRESENTER NOTES
Some knife-type injectors probably reduce odor and gaseous emissions the most and will also leave good residue cover.  They may be limited on the volume of manure they can apply per acre and still achieve complete coverage.
PRESENTER NOTES
Key Discussion Topics
1.Example 1: a Nebraska 11,000 head feedlot.  Additional examples are attached at the end of the power point presentation.  Pick the example most appropriate for you audience.
2. For this feedlot, 1080 tons of nitrogen and 240 tons of phosphorus are brought onto the farm annually.  Most inputs are as purchased feeds and purchased animals.
3.For this feedlot, 430 tons of nitrogen and 120 tons of phosphorus leave the farm as managed outputs annually.  All outputs are as cattle sold for slaughter.
4.For this feedlot, the nitrogen imbalance is 650 tons annually.  Most of this nitrogen is lost as ammonia volatilization into the atmosphere.  Some excess nitrogen is added to the soil as organic and ammonium-N.   This nitrogen is in excess of what can be used by the cropping program and it is likely to transform to nitrate-N and move towards groundwater. 
References
   Lesson 2:   pages 11