Agricultural BMPs to Reduce N Emissions

1. Agricultural BMPs to Reduce N Emissions Jessica G. Davis Colorado State University

2. Types of BMPs • Livestock Producers • Nutrition • Production site • Manure storage and treatment • Land application of manure • Crop Producers • Fertilizer management practices

3. BMPs: Nutrition—Basic Principles • Don’t overfeed protein • Analyze feeds regularly • Phase feeding • By growth stage • By sex • By productivity • PRECISION FEEDING

4. BMPs: Nutrition--swine 12.5% 55.4% Wendy Powers, Iowa State University

5. BMPs: Nutrition--Feedlot Cattle • Cole et al. (2005) found that increasing crude protein in feeder diets from 11.5 to 13.0% resulted in increases in NH3 loss from 60-200%

6. Feeding trial type Trial Slurry type components Fresh Stored % applied N lost as ammonia Crude Protein level 13.6% 31b 12b 19.4% 68a 29a BMPs: Nutrition—Dairy (NH3 loss from slurry applied to soil) Misselbrook et al., 2005 (lab study)

7. BMPs: Nutrition--layers • Diet acidification minimizes volatilization of ammonia by acidifying excreta 42% Wendy Powers, Iowa State University

8. BMPs: Livestock Production Site • Dust control • Frequent manure harvesting • Pen moisture management • Stocking density • Watering • Reduce surface pH

9. Manure Harvesting Manure not yet harvested, > 2” deep Wind Manure harvested within previous 3 days, < 1” deep

10. Pen Moisture Dust and odor events are driven principally by the effect of short-term weather patterns on the moisture content of the manure pack on the corral surface. 100 90 80 70 60 Dust/Odor Potential 50 40 Dust Odor 30 20 10 0 0 10 20 30 40 50 60 70 80 90 100 Moisture Content (%wb)

11. 1 2 3 4 Feed apron Moisture Dynamics Vary Within Corrals Water trough High activity; High moisture Low activity; Low moisture

14. BMPs: Livestock Production Site • Feedlot Surface • Application of a urease inhibitor onto the feedlot surface every 8 days reduced NH3 loss from 49-69% • Lab study by Parker et al. (2005)

15. Washing Wall • 33-50% reduction in NH3 loss

16. Biofilter • Reduces NH3 loss 50-60%

17. Alum in Broiler Litter

18. Bedding types--Dairy Annual loss of ammonia nitrogen 100 heifers using different beddings N loss (lbs) Composted manure solids Chopped newspaper Chopped straw Pine shavings Sand Chopped corn stalks Misselbrook and Powell (2005)

19. BMPs: Manure Storage and Treatment • Minimize storage time • Cover piles and lagoons • Divert rainfall and runoff from stockpiles • Aerobic lagoons reduce gaseous N loss and conserve N • Constructed wetlands increase N2O loss (denitrification) • Aerobic/anaerobic alternating lagoons increase N2O loss • Anaerobic digestors conserve N

21. Dairy Lagoons • A self-forming crust on dairy lagoons reduced NH3 loss by ~50% (Misselbrook et al., 2005) • Composting • Composting feedlot manure with different beddings • Straw bedding -- 42% N lost • Wood chip bedding—12% N lost • There was little difference in N2O loss; apparently, the difference was mainly in NH3 loss. • (Hao et al., 2004)

22. BMPs: Land Application of Manure • Incorporate immediately after application • Injection of slurries • Drop nozzles for sprinkler irrigation

24. BMPs: Fertilizer Management • Fertilizer Selection • In general, dry fertilizers have less NH3 loss. • In calcareous soils, ammonium nitrate has the lowest amounts of NH3 loss. • Ammonium sulfate has the highest loss. • Urea is moderate. • Application Method • Band N fertilizers to reduce NH3 loss. • Broadcasting increases N loss. • Fertilizer Application Rate • Higher rates result in higher N loss. • Use agronomic rates.

25. BMPs: Fertilizer Management • Timing • Synchronize application with crop demand. • Use slow-release fertilizers. • Soil Properties • NH3 loss is greatest in • Sandy, low organic matter soils • High temperatures • Moist soil conditions—Don’t over-irrigate! • Tillage Practices • No-till increases N loss due to reduction in both soil evaporation and infiltration of fertilizers.

26. Impact of improved management on reductions in ammonia emission from dairy farms Together these management practices can reduce ammonia N loss by 65-70%. Mark Powell, USDA-ARS, Madison, WI

27. Thorough literature review Cost of BMPs Effectiveness of BMPs BMP adoption rates Decision tree to help agricultural producers choose appropriate BMPs Future Needs