1
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- Curtis Dell
- USDA-ARS-PSWMRU
- University Park, PA
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2
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- 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
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3
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- 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
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4
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- 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
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5
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- 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
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6
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- Determine if N2O emissions from a corn field differ when N
fertilizer is applied as NH4NO3,
dairy manure,or a combination of the two.
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7
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8
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9
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- 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
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10
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- 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
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11
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- 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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12
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13
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14
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- Gravimetric soil water content
- Soil inorganic N (2004 only)
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15
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16
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17
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18
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19
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20
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21
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22
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- 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
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23
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- 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.
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24
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- Bill Priddy, MaryKay Krasinski, Dianna Sturrock, and Jessica Agnew for
all their efforts in the field and lab
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