Nitrogen, Food Production and Climate Change

Category: Education

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Role of nitrogen fertilizers in food production vis-à-vis climate change


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Throughout human history, engineering has driven the advance of civilization The century ahead poses challenges as formidable as any from millennia past The NAE has identified 14 Engineering's Grand Challenges or areas awaiting engineering solutions in the 21st century


Make solar energy economical Provide energy from fusion Develop carbon sequestration methods Manage the nitrogen cycle Provide access to clean water Restore and improve urban infrastructure Advance health informatics Engineer better medicines Reverse-engineer the brain Prevent nuclear terror Secure cyberspace Enhance virtual reality Advance personalized learning Engineer the tools of scientific discovery GRAND CHALLENGES FOR ENGINEERING

Nitrogen, Food Production and Climate Change:

Nitrogen, Food Production and Climate Change Bijay Singh FNA, FNAS, FISSS INSA Senior Scientist Ex-ICAR National Professor Punjab Agricultural University, Ludhiana 141 004 Email: [email protected]

Food Security:

Food Security Ability to obtain sufficient food on a daily basis

Modern Food Supply:

Modern Food Supply World food supplies have more than kept up with human population growth 1950 - 2.5 billion people - average daily diet was less than 2,000 calories/person. 2001 - 6.0 billion people - world food supply can provide more than 2,500 calories/person. 2007 More than 4,000 calories of food were made per day for people living in rich nations like U.S.A. 2011 ….. Obesity is becoming a problem in some developing countries as well

Modern Food Supply:

Modern Food Supply About 1 in 5 people in the developing world are considered chronically hungry. 24,000 people die every day from hunger 90% of hunger-related deaths - due to chronic malnutrition; only 10% - due to wars and famine.


INCREASING FOOD DEMAND World population is increasing ~ 3%/year World food production increasing ~ 2%/year


GLOBAL FOOD SECURITY The world’s most important renewable resource → Crop Production What stands between people and starvation? → Crops Production 50% of calories and 60% of protein is supplied by → Crop Production

Essential Plant Nutrients:

Essential Plant Nutrients 16 essential elements C, H, O – air and water, photosynthesis N, P, K, S – major elements, applied as fertilizers Ca, Mg – lime elements Fe, Mn , B, Mo, Zn, Cu, Cl – micro or minor elements, required at very low levels I and Co – important for animals FERTILIZER: Any substance which is applied to soil to supply certain essential elements for the plant growth and nutrition

Food production and Nitrogen use in India:

Food production and Nitrogen use in India

Fertilizer N inputs in Indian agriculture:

Fertilizer N inputs in Indian agriculture Nitrogen – urea, calcium ammonium nitrate, ammonium sulphate

Important Things about Nitrogen :

Important Things about Nitrogen Unreactive N is N 2 , 78% of earth’s atmosphere Reactive N is Nr , all biologically, chemically and physically active N compounds in the atmosphere and biosphere of the Earth N 2 is naturally converted to Nr primarily by biological nitrogen fixation (BNF) <1% of organisms are able to convert N 2 to Nr N is the limiting nutrient to many ecosystems N 2 is converted to Nr by humans via Fossil fuel combustion The Haber-Bosch process Cultivation-induced BNF

PowerPoint Presentation:

‘The World is running out of N’ – William Crookes, President BAAS (1898)

N deposition:

N deposition Nitrogen is emitted as NOx to the atmosphere by fossil fuel combustion Nitrogen is emitted as NH 3 and NO x from food production Once emitted, it is transported and deposited even to ecosystems not intended to receive 3- to 5-fold increase in N emissions over the last century

PowerPoint Presentation:

Year Reactive N emitted as NO x and NH 3 and then deposited to the Earth’s surface as NO y and NH x 1860 34 Tg N year -1 1995 100 Tg N year -1 2050 200 Tg N year -1 N deposition to ecosystems in the absence of human influence is generally ~0.5 kg N ha −1 yr −1 or less Average N deposition rates exceeding 10 kg N ha −1 yr −1 are already being observed in large regions of the world

PowerPoint Presentation:

Estimated N deposition from global total N (NO y and NH x ) emissions, totaling 105 Tg N y −1 . The unit scale is kg N ha −1 y −1 , modified from the original units (mg m –2 y –1 ) (Dentener et al., 2006) 1860 How extensive is Nr distribution?

There are significant effects of Nr accumulation within the atmosphere, geosphere and biosphere:

There are significant effects of Nr accumulation within the atmosphere, geosphere and biosphere Increases in: tropospheric O 3 , N 2 O and PM2.5 soil acidity and N concentrations coastal / surface water N concentrations drinking water NO 3 concentrations Decreases in: stratospheric O 3 Leads to: loss of biodiversity in terrestrial and aquatic ecosystems human health effects changes in earth’s radiation balance soil health effects

Nitrogen and Climate change:

Nitrogen and Climate change

PowerPoint Presentation:

What is climate? Climate is an average of weather (temperature, rainfall...) over a “long” time (more than 2-3 weeks).

PowerPoint Presentation:

What makes climate change? Changes in the sun Changes in the earth's orbit Changes in the clouds Changes in ice sheets Volcanic eruptions Changes in the gases in the atmosphere (Greenhouse effect) Internal Wiggles (for example El Nino) Some cause bigger changes, some cause small changes Some cause slower changes, some cause fast changes Some cause changes that last , some cause changes that go away fast Climate changes can be natural or human caused . Humans can affect the climate by changing the gases in the atmosphere (greenhouse effect)

PowerPoint Presentation:

The Greenhouse Effect

PowerPoint Presentation:

Carbon dioxide (CO 2 ) is a major greenhouse gas Human burning of fossil fuels, and plants releases CO 2 Human influence on climate: the Greenhouse Effect

PowerPoint Presentation:

The most important human-affected greenhouse gases are: Greenhouse Gas Life Span in the Atmosphere Heat-Trapping Effectiveness (1 is lowest) Carbon Dioxide (CO 2 ) 2-30 years 1 Methane (CH 4 ) 6-11 years 20-30 (21) Nitrous Oxide (N 2 O) 120-150 years 296 Fluorinated Gases 65-111 years 15,000-20,000

PowerPoint Presentation:

Atmospheric concentrations of nitrous oxide over the last 10,000 years (large panels) and since 1750 (inset panels). Measurements are shown from ice cores (symbols with different colours for different studies) and atmospheric samples (red lines). The corresponding radiative forcings are shown on the right hand axes of the large panels. (Source IPCC, 2007)

N Fertilizers and N2O emissions:

N Fertilizers and N 2 O emissions More than a third (38%) of all N 2 O emissions are anthropogenic and are primarily associated with N fertilizers and manure applied to soils In 2005, agriculture contributed 58% of total anthropogenic emissions of N 2 O to the atmosphere

Nitrogen fertilizers and N2O production in agricultural soils:

Nitrogen fertilizers and N 2 O production in agricultural soils Generally there is large emission of N 2 O immediately after application of fertilizer N On an average , emission of N 2 O from different fertilizer types: can be calculated as: N 2 O emitted = 1.25 % of kg N applied

N2O emissions from various source categories in India in Gg-N2O (Source: Garg et al. 2006):

N 2 O emissions from various source categories in India in Gg-N 2 O (Source: Garg et al. 2006) Source categories 1985 1990 1995 2000 2005 Compounded annual growth rate (%) Synthetic fertilizer use 80 94 109 129 151 3.2 Field burning of agricultural residues 15 18 21 21 20 1.4 Indirect soil emissions 17 19 21 25 30 2.9 Manure management 4 5 6 6 8 3.9 Fossil fuel combustion 7 9 12 15 19 4.9 Industrial processes 6 7 9 12 16 5.0 Wastes 5 6 7 8 9 2.8 Total N 2 O 134 158 185 217 253 3.2

PowerPoint Presentation:

N 2 O emissions in India in the reference scenarios 2000 and 2020 (Source: Garg et al. 2004)

What can we do with the emerging N cycling scenario? :

What can we do with the emerging N cycling scenario?

PowerPoint Presentation:

Controlling NOx emissions from fossil-fuel combustion : 25 Tg to 7 N yr −1 to Increasing FUE will reduce Nr creation by ~15 Tg N yr -1 Improved animal management strategies would decrease Nr creation by ~15 Tg N yr −1 Providing sewage treatment to only half the 3.2 billion people living in cities: 5 Tg N yr −1 converted to N 2

What can we do with the emerging scenario of fertilizer N in agriculture?:

What can we do with the emerging scenario of fertilizer N in agriculture? Avoid indiscriminate use of fertilizer N in agriculture because it leads to N deposition, global warming and environmental degradation Fertilizer N, if used judiciously can enhance soil health and help mitigate climate change

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