Nitrous%20Oxide%20Emissions%20from%20Soils%20Receiving%20a%20Combination%20of%20Dairy%20Manure%20and%20Mineral%20Nitrogen%20Fertilizer

1
Nitrous Oxide Emissions from Soils Receiving a
Combination of Dairy Manure and Mineral Nitrogen
Fertilizer

• Curtis Dell
• USDA-ARS-PSWMRU
• University Park, PA

2
Nitrous Oxide (N2O)

• Approximately 300 times more effective than CO2
  as a greenhouse gas
• Agriculture is a significant contributor
• By-product of both nitrification (aerobic) and
  denitrification (anaerobic)
• Denitrification generally believed to be largest
  N2O source in soils, but rates vary greatly
  depending on soil aeration

3
Manure Management In NE US

• Large number of dairy, poultry, and swine
  facilities
• Limited land base for manure application
• Water quality problems resulting from excess P
  accumulations in soil
• Nutrient management planning required in several
  NE/Chesapeake Bay states

4
Nutrient Management In NE US

• Manure application in excess of plant P
  requirement discouraged/prohibited in many
  locations
• A larger land base for spreading or costly waste
  treatment required
• Combinations of manure and mineral N fertilizers
  used more frequently

5
Manure Applications and N2O Emissions

• Greater potential for N2O production when manure
  is fertilizer source because of addition of
  organic C
• Energy source for denitrifying bacteria
• Stimulates activity by general microbial
  population, depleting O2 supply
• Combinations of organic and mineral N fertilizers
  may have even greater potential for emissions
• Organic C from manure and readily available N
  from mineral fertilizer

6
Objectives

• Determine if N2O emissions from a corn field
  differ when N fertilizer is applied as NH4NO3,
  dairy manure,or a combination of the two.

7
Methods
8
N Source Treatments
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N Source Treatments

• All mineral fertilizer
• 75 kg ha-1 N as NH4NO3 preplant-incorporated
• 75 kg ha-1 N as NH4NO3 side dress, surface
• 60 kg ha-1 mineral P preplant, incorporated

10
N Source Treatments

• All mineral fertilizer
• 75 kg ha-1 N as NH4NO3 preplant-incorporated
• 75 kg ha-1 N as NH4NO3 side dress, surface
• 60 kg ha-1 mineral P preplant, incorporated
• P-based manure (31 Mg ha-1)
• 75 kg ha-1 N as manure preplant, incorporated
• 75 kg ha-1 N as NH4NO3 side dress, surface
• 60 kg ha-1 P as manure preplant, incorporated

11
N Source Treatments

• All mineral fertilizer
• 75 kg ha-1 N as NH4NO3 preplant-incorporated
• 75 kg ha-1 N as NH4NO3 side dress, surface
• 60 kg ha-1 mineral P preplant, incorporated
• P-based manure (31 Mg ha-1)
• 75 kg ha-1 N as manure preplant, incorporated
• 75 kg ha-1 N as NH4NO3 side dress, surface
• 60 kg ha-1 P as manure preplant, incorporated
• N-based manure (62 Mg ha-1)
• 150 kg ha-1 N as manure preplant, incorporated
• 120 kg ha-1 P as manure preplant, incorporated

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Vented chambers
13
Sampling and Analysis
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Additional Measurements

• Gravimetric soil water content
• Soil inorganic N (2004 only)

15
Results
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Rainfall
Source Penn State Univ. Dept. of Meteorology
17
Soil Water Content
18
Soil Nitrate 2004
19
N2O Emissions 2003
20
N2O Emissions 2004
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Estimated Seasonal N2O Emissions
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Conclusions

• N2O emissions are potentially greater when all or
  part of the N was supplied by manure
• Application of only manure or a combination of
  manure and mineral N resulted in similar emissions

23
Implications

• Utilization of manures as a fertilizer source
  must be a accounted for in the estimation of N2O
  emissions from cropping systems.
• Application of manure to a larger land base, even
  at lower rates, has the potential to increase
  overall annual N2O emissions.

24
Acknowledgements

• Bill Priddy, MaryKay Krasinski, Dianna Sturrock,
  and Jessica Agnew for all their efforts in the
  field and lab