C.S. Snyder, PhD, CCA

Nitrogen Program Director

Nitrogen Contributions to the Greenhouse Gas Effect and

Global Warming

Acknowledgements

• Dr. Tom Bruulsema

• Dr. Tom Jensen

Background

• N is essential to the survival of all life

• Over 40% of the people on Earth owe their existence to the food production made possible by N fertilizers

• “Human alterations of the N cycle have caused a variety of environmental and human health problems ranging from too little to too much reactive N in the environment.” (Woods Hole Research Center)

http://www.whrc.org/policy/global_nitrogen.htm

Millenium Ecosystems Assessment

• N- ecological & environmental effects• eutrophication of 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 destruction in stratosphere (increased

UV-B radiation on Earth) • Contribution to global warming (GHGs). • Increased health effects include:

– asthma and respiratory malfunction, – pollen production, and increased allergies and

asthma– bluebaby syndrome – 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.”

Nutrient Management (Ch.9)by Robert Howarth & others (2005)

Greenhouse Gases (GHGs)and their sources

• Carbon Dioxide (CO2): fossil fuels (oil, natural gas, and coal), solid waste, trees and wood products, and also as a result of other chemical reactions (e.g., manufacture of cement).

• Methane (CH4): production and transport of coal, natural gas, and oil; livestock and other agricultural practices and by the decay of organic waste in municipal solid waste landfills.

• Nitrous Oxide (N2O): agricultural and industrial activities, as well as during combustion of fossil fuels and solid waste.

• Fluorinated Gases: (Hydrofluorocarbons, perfluorocarbons, and sulfur hexafluoride): synthetic, powerful greenhouse gases from a variety of industrial processes. – Sometimes used as substitutes for ozone-depleting substances

(i.e., CFCs, HCFCs, and halons). Typically emitted in smaller quantities, but because they are potent GHGs, they are sometimes referred to as High Global Warming Potential gases (“High GWP gases”).

GWP = Global Warming PotentialN2O x 296 = CO2 equivalentCH4 x 21 = CO2 equivalent

Sources: EPA, IPCC

United Nations Educational, Scientific, and Cultural Organization & Scientific Committee on Problems of the Environmenthttp://www.icsu-scope.org/unesco/070424%20(w)%20USPB04%20En.pdf

Public Perception ….. Ag is Bad Actor ….. Affecting Air Quality and Water Quality

Billions

0

1

2

3

4

5

6

7

8

9

10

1950 1970 1990 2010 2030 2050

Less Developed Regions

More Developed Regions

Source: United Nations, World Population Prospects: The 2004 Revision (medium scenario), 2005.

World Population Growth in More and Less Developed Countries

http://www.prb.org/Publications/GraphicsBank/PopulationTrends.aspx

20% more people in ~ 20 years

Food, fiber, and fuel demands will continue to increase

…… what will the environmental impact be?

Consumption of N Sources

Gap Between CO2 Emissions of Developed and Developing Regions (FAO)

CO2 emissions per capita, 2002

Global pressures on developed countries are increasing

http://www.ipni.net/ppiweb/bcrops.nsf/$webindex/6F2F57CBF1C5209685257394001B2DD0/$file/07-4p16.pdf

IPNI Better Crops article, Issue 4 of 2007

Best Management Practices to Minimize Greenhouse Gas Emissions

Associated with Fertilizer Use

IPNI Review Paper (in press)

Greenhouse Gas Emissions from Cropping Systems and the Influence of Fertilizer Management

Agriculture’s Share of GHG Emissions is Not Increasing

Agriculture< 10% of total U.S. GHG

Distribution of GHG Emissions

Estimates of N2O Emissions from Cropland in 1995 (adapted from IFA/FAO, 2001)

Region Area

(million ha)

Fertilizer N Applied

Animal Manure N Applied

N2O-N emitted

total Fertilizer-induced 1

million tonnes % of total

Canada 46 1.58 0.21 0.067 0.016 24

U.S. 190 11.15 1.58 0.316 0.112 35

World 1,436 73.48 20.66 3.150 0.735 231 Estimated using IPCC emission factor of 1%Recently published reports suggest terrestrial and aquatic N2O-N emissions may range from 2 to 5% of “new N”

Food Yield/Net GWP.01

.09

.02

.02

.02

.02

.01

.01

Range of N2O Emission Among N Sources can Vary Greatly

• Report 1 (Stehfast & Bouwman, 2006)

– 0 to 46% of applied N

• Report 2 (Granli & Bockman, 1994)

– 0 to 7% of applied N

• Report 3 (Eichner, 1990)

– 0 to 7% of applied N

• Report 1– Median among N

sources ranged from: 0.26 to 1.56 kg of N/ha

N Rates Above Agronomic Optimum Can Increase Risk of N2O

Emission

Loss of NO3 - N to Water Resources May Also Impact N2O Emissions

Kg/ha.01 .01- 0.10.1 to 11 to 55 to 10>10

SPARROW - Modeled Estimate of N and P Discharge in Watersheds of the Mississippi R. Basin

Water Quality/Quantity Best Management Practices for Florida Vegetable and Agronomic Crops. (2005)

How much of the nitrate-N leached into shallow groundwater , or reaching surface water is subject to denitrification and N2O emission ?

Nitrogen Use Efficiency

• “…… estimated NUE for cereal production ranges from 30 to 35%.” 

Improving Nitrogen Use Efficiency for Cereal Production ( 1999 Agronomy Journal 91:357-363)

N Recovery and NUE are Affected by Other Essential Nutrients

N Loss Consequences Requiring Management Attention

• Decreased crop production and profitability – Inefficient land use, reduced performance of other

crop inputs, reduced water use efficiency

• Water resource contamination– eutrophication: lakes, streams, rivers, estuaries– groundwater contamination– coastal water contamination - urea and harmful algal

blooms (neurotoxin poisoning)

• Air pollution– Ammonia and particulates, nitrous oxide and NOx

(global warming, stratospheric ozone depletion, acid rain)

Nutrient Use Efficiency and Effectiveness:Indices of Agronomic and Environmental Benefit

http://www.ipni.net/ipniweb/portal.nsf/0/d58a3c2deca9d7378525731e006066d5/$FILE/Revised%20NUE%20update.pdf

NUE Term Calculation Reported Examples

PFP - Partial factor productivity

Y/F 40 to 80 units of cereal grain per unit of N

AE - Agronomic Efficiency

(Y-Y0)/F 10 to 30 units of cereal grain per unit of N

PNB - Partial nutrient balance (removal to use ratio)

UH/F 0 to > 1.0 - depends on native soil fertility and fertility maintenance objectives<1 in nutrient deficient systems (fertility improvement)

>1 in nutrient surplus systems (under replacement)

Slightly less than 1 to 1 (system sustainability)

RE – Recovery efficiency of applied nutrient

(U-U0)/F 0.1 to 0.3 - proportion of P input recovered first year

0.5 to 0.9 - proportion of P input recovered by crops in

long-term cropping systems

0.3 to 0.5 - N recovery in cereals-typical

0.5 to 0.8 - N recovery in cereals- best management

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

Increased Farmer Interest in Better N Management

• Increased N costs• Better crop prices• Calibration and

verification of newer technologies

• Improved farmer skills and availability of professional guidance by crop advisers

“The Market” Nov.1, 2007

0.5

0.6

0.7

0.8

0.9

1.0

1.1

1.2

1.3

1.4

1960 1965 1970 1975 1980 1985 1990 1995 2000 2005

bu p

er lb

of

NCorn grain produced in the U.S. per unit

of fertilizer N used, 1964 to 2005.

0.760.76

1.151.15

51% increase in N efficiency12% increase in N fertilizer use

Since 1975:

*

*Application rate for 2004 estimated as avg of 2003 & 2005.

Data sources: USDA Ag Chem Use Survey & Annual Crop Production.

Effects of Crop Harvest N Removal on Net Anthropic Nitrogen Input (NANI)

Source: McIsaac, 2006.

Figure 1. Net anthropogenic N input (NANI) in major sub-basins of the Mississippi River Basin estimated from state level statistics.

Fertilizer N in FL and GHG Emission225, 000 x 0.01= 2,250 tons N2O –N emitted

(assuming IPCC 1% factor)

N x 1.57 = 3,533 tons of N2ON2O 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

Source: AAPFCO

• N source, rate, placement , and timing …. which may include– Urease inhibitors– Nitrification inhibitors– Slow-release materials– Controlled-release materials

• In combination with appropriate, site-specific cropping system and conservation practices – (e.g. conservation tillage, cover crops,

vegetative buffers, managed drainage, wetlands, bioreactors, etc.)

• Fertilizer N BMPs can help minimize potential for residual NO3-N accumulation & losses

http://www.fertilizer.org

http://www.ipni.net/bettercrops

http://www.floridaagwaterpolicy.com/BestManagementPractices.html

CONCLUSIONS• Appropriate fertilizer N helps increase crop

biomass to restore & maintain soil organic matter (SOM)

• Tillage practices with the least soil disturbance help maintain SOM

• Intensive crop management can help minimize GHG emissions, and lower GHG emission/unit of crop or food produced

• Fertilizer N contributions to agricultural GHG emissions can range widely, BUT agricultural emissions are relatively small compared to other source emissions

• We must continue to strive to improve NUE

Governor Signs Florida Greenhouse Gas Targets

• MIAMI: Reuters: July 13, 2007– "The Republican governors of California and Florida gave the

Bush administration the cold shoulder on Friday as Florida set new limits on greenhouse gas emissions and signed cooperation pacts on climate change with Germany and Britain.

• Florida targets call for state utilities to reduce GHG emissions:– to 2000 levels by 2017– to 1990 levels by 2025 and – by 80 percent of 1990 levels by 2050.

http://lightblueline.org/node/249

•California officials say their 2004 law is tougher than the new national standard. It would have required the auto industry to cut emissions by one-third in new vehicles by 2016 or reach an average of 36.8 mpg.”•Twelve other states — CT, ME, MD, MA, NJ, NM, NY, OR, PA, RI, VT, WA — have adopted the CA emissions standards and the governors of AZ, CO, FL and UT have said they plan to adopt them. The rules also are under consideration in Iowa.•“The auto regulations are a major part of California's global warming law, which aims to reduce greenhouse gases statewide by 25 percent — to 1990 levels — by 2020. Auto emissions account for about 17 percent of the state's proposed reductions.”

January 2, 2008

http://ap.google.com/article/ALeqM5jJH569QSBl-5FfOe4F9liGjADk3gD8TTUJVO0

http://www.palmbeachpost.com/news/content/business/epaper/2007/12/23/a1f_biomass_1223.html

Dec. 23, 2007

• Eric Waschman- interim director of the Florida Institute for Sustainable Energy at the U. of Florida – champions making ethanol from citrus peels and stems because it's taking advantage of waste from a crop that was going to be grown and harvested anyway.

• Ag. Commissioner - Charles Bronson- thinks Florida could grow no less than 30 percent of its annual fuel supply.

• He doesn't want farmers to stop growing their staple fruits and vegetables in favor of crops for biofuels. Instead, they should add extra plantings and use that as an energy source

http://www.emissionstrading.com/seminar/

QUESTIONS ?

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