Nitrous Oxide Emissions from Dairy Farm Fields

1. Nitrous Oxide Emissions from Dairy Farm Fields Brian Richards Marina Molodovskaya Olga Singurindy Tammo Steenhuis (Project Director) Department of Biological & Environmental Engineering Jon Warland University of Guelph

2. Acknowledgments • Funding: USDA NRI - Agricultural Air Quality Program • Todd Walter (BEE) • Curt Gooch (BEE/PRO-DAIRY) • Peter Wright (NRCS; co-PI) • Harlan Nafziger & Cornell ASTARC staff • Hardie Farms (Lansing NY) • Doug Caveney, Nate Richards (construction)

3. Project goal Measure nitrous oxide (N2O) emissions from NY dairy farm fields USDA agricultural air quality program concern: Accurately assess agricultural contributions Understand effects of management practices and potential BMPs No planned regulation of field emissions

4. EPA concern over N2O • catalyzes ozone destruction • ranked as #4 greenhouse gas RankConcentration CO2 370 ppm Methane 1750 ppb Water vapor ~0.2-3 % N2O 315 ppb

5. Nitrous oxide in the atmosphere • Increasing @ 0.25%/year = 3.9 Tg/year • Agriculture thought to contribute ~3.3 Tg/year • In US: 72% of human inputs due to • soil management • livestock

6. Agricultural Sources • nitrification • up to 3% of total oxidized NH4 to N2O • soil denitrification • a function of soil saturation • downstream denitrification • of leached nitrate

7. Why look at NY dairy farms? 1) Nutrient flows: N budgets • Substantial N2 fixation, feed importation and fertilizer imports make dairy fields a significant regional N factor

8. 2) Development pressure Many non-farm neighbors pressure for manure odor control practices may increase N2O potential Taxes & land cost Pressure to increase herd size relative to land base leads to high loadings Lancaster Co, PA

9. 3) Hydrology Soils prone to seasonal saturation or near-saturation, favoring denitrification

10. significant N importation • Nutrient flows • Development pressure • Hydrology high manure loadings; odor control practices soil saturation and near-saturation Combine for significant denitrification potential

11. Gaseous losses 50% ?? 35% soil denitrification 11% river denitrification 3% ammonia volatilization Riverine 20% Northeast N budget: storage and losses As % of input N: Storage* 18% Food/wood 11% Van Breemen et al. 2002

12. Measuring N2O Emissions Challengemicrobial processes → dependent on changing conditions (temperature, saturation, N forms present, substrate) Two approaches used • Micrometeorology sensors: field-scale determination of average field emissions • Small-scale chambers: effects of localized variability

13. Micrometeorological sensing • Eddy covariance: watching concentrations change as wind eddies roll across field: 10 measurements/second • measure multiple additional parameters to calibrate and confirm EC calculations: 3-D wind, CO2, water vapor, energy budget • Research Question: How will different agricultural practices combined with seasonal climate effects impact N2O fluxes throughout the year?

14. Micrometeorological field instrumentation Temperature probe Air sample intake Rain gauge CO2 Water vapor Sonic anemometer Radiometer Sensor processors Data logger Trace gas analyzer

15. Example of multi-parameter micrometeorological field data (May 20-24, 2006) data unfiltered

16. A C(C) C(A) Cornell Animal Science Teaching and Research Farm Harford, NY Corn(winter spreading) December 2006 -February 2008 Spring 2008: field split corn / alfalfa Alfalfa (summer speading) April-October 2006

17. Must run 24/365 to catch events ...

18. Field N2O flux example data (alfalfa, 2006) Rainfall Field N2O flux Manure application begins Temp

19. Manure application started Corn Field (prelim) Average N2O-N Flux 0.032 ug m-2 s-1 1.15 g ha-1 hr-1 Maximum (spring thaw): 0.14 ug m-2 s-1 5.04 g ha-1 hr-1

20. Ongoing micromet work • intensive data filtering, calculation and synthesis needed to quantify meaningful emission rates and to correlate with conditions & management • this cropping season: two treatments from same sampling point • determining when and where to look will simplify future field work

21. Chamber-scale studies • Use transects or grid arrays of chambers to study effects of soil moisture gradients or other features across fields • Intensive, short campaigns • Samples collected in field, analyzed in lab

22. Chamber study results (fall-spread manure): soil moisture effects on emissions

23. Soil temperature and tillage effects 15 0 -15 300 Soil Temp. (oC) N2O flux (ng m-2 s-1)

24. Combined effects of moisture and soil temperature 10 SoilTemp. (oC) N2O flux (ng m-2 s-1) 0 40 50 60 70 80 Soil Saturation (%)

25. Ongoing chamber-scale studies • Large transects being readied for installation • Integrating with micromet EC study to compare spot vs. field-integrated results • Integrating with push-pull N-isotope studies of denitrification in fields with shallow groundwater systems (Todd Walter, Todd Anderson) • Hydrology correlations

26. Ongoing tasks • integrating field- and chamber-scale measurements • calculation and synthesis needed to quantify meaningful N2O emission rates/ranges • need context of overall nutrient balance • balancing nutrient/manure BMPs: crop yields, N efficiency, water quality ... and air quality

27. Thank you!

29. Simplified system components & layout