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Nitrogen Contributions to the Greenhouse Gas Effect and Global Warming. C.S. Snyder, PhD, CCA Nitrogen Program Director. Acknowledgements. Dr. Tom Bruulsema Dr. Tom Jensen. Background. N is essential to the survival of all life
C.S. Snyder, PhD, CCA
Nitrogen Program Director
eutrophicationof coastal marine ecosystems, freshwater lakes
acid rain effects on freshwater and terrestrial ecosystems
loss of biodiversity: aquatic and terrestrial
ozone creation @ ground-level (leads to loss of agricultural and forest productivity)
ozone destructionin stratosphere (increased UV-B radiation on Earth)
Contribution toglobal warming(GHGs).
Increased health effects include:
asthma and respiratory malfunction,
pollen production, and increased allergies and asthma
risk of cancer and other chronic diseases from nitrate in drinking water
risk of a variety of pulmonary and cardiac diseases from production of fine particles in the atmosphere.
“Human activity has greatly increased the flux of nutrients through the landscape, roughly doubling the global flux of nitrogen and tripling the flux of phosphorus in the landscape over natural values.”
“half the synthetic nitrogen fertilizer ever used on Earth has been utilized since 1985.”
Millenium Ecosystems AssessmentNutrient Management (Ch.9)by Robert Howarth & others (2005)
GWP = Global Warming Potential
N2O x 296 = CO2 equivalent
CH4 x 21 = CO2 equivalent
Sources: EPA, IPCC
United Nations Educational, Scientific, and Cultural Organization
& Scientific Committee on Problems of the Environment
20% more people in ~ 20 years
Less Developed Regions
Food, fiber, and fuel demands will continue to increase
…… what will the environmental impact be?
More Developed Regions
Source: United Nations, World Population Prospects: The 2004 Revision (medium scenario), 2005.
CO2 emissions per capita, 2002
Global pressures on developed countries are increasing
Associated with Fertilizer Use
IPNI Review Paper (in press)
IPNI Better Crops article, Issue 4 of 2007
Greenhouse Gas Emissions from Cropping Systems and the Influence of Fertilizer Management
< 10% of total U.S. GHG
Recently published reports suggest terrestrial and aquatic N2O-N emissions may range from 2 to 5% of “new N”
SPARROW - Modeled Estimate of N and P Discharge in Watersheds of the Mississippi R. Basin
0.1 to 1
1 to 5
5 to 10
How much of the nitrate-N leached into shallow groundwater , or reaching surface water is subject to denitrification and N2O emission ?
Water Quality/Quantity Best Management Practices for Florida Vegetable and Agronomic Crops. (2005)
Improving Nitrogen Use Efficiency for Cereal Production
( 1999 Agronomy Journal 91:357-363)
Indices of Agronomic and Environmental Benefit
F-amt. nutrient applied, Y- yield of harvested portion with applied nutrient, Y0- yield of harvested portion with no applied nutrient, UH –nutrient content of harvested portion of crop, U –total nutrient uptake in aboveground biomass with nutrient applied, U0 –total nutrient uptake in aboveground biomass with no nutrient applied
“The Market” Nov.1, 2007
12% increase in N fertilizer use
Since 1975:Corn grain produced in the U.S. per unit of fertilizer N used, 1964 to 2005.
*Application rate for 2004 estimated as avg of 2003 & 2005.
Data sources: USDA Ag Chem Use Survey & Annual Crop Production.
225, 000 x 0.01= 2,250 tons N2O –N emitted
(assuming IPCC 1% factor)
N x 1.57 = 3,533 tons of N2O
N2O x 296 = 1.05 million tons GWP CO2 equivalent
All GHGs in FL in 2007 (Adams, FDEP) :
268 million tons CO2 equivalent
Portion of total that is “fertilizer N induced”
= (1.05/268) x 100 = 0.4% of all GHGs
Fertilizer N BMPs can help minimize potential for residual NO3-N accumulation & losses
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