R. Shanthini 07 Jan 2012
“In the end we will conserve only what we love;
we will love only what we understand; and
we will understand only what we have been taught.”
– Baba Dioum
CP551 Sustainable Development
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Module 8:
Use of fertilizers and pesticides, green revolution,
and agricultural biotechnology in the agricultural sector,
and their impact on sustainable development.
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0
500
1,000
1,500
2,000
2,500
3,000
3,500
4,000
4,500
1950 1960 1970 1980 1990 2000 2010
Paddy Production in Sri Lanka 1952 - 2006
http://www.statistics.gov.lk/agriculture/Paddy%20Statistics/TB3_NP_Annual_1952_2006.pdf
Harvested area (in ‘000 hect.)doubled
Production (in ‘000 Tonnes)increased 5.5 times
Average Yield (kg / hect.)increased 2.6 times
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How was it possible?
Fact:
Average yield of paddy per area in Sri Lanka increased by a factor of 2.6 during 1952 to 2006,
which keeps pace with
the Sri Lanka population increase by a factor of 2.37 during 1950 to 2005.
http://www.statistics.gov.lk/ and http://esa.un.org/unpp/p2k0data.asp
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Ploughing
in 2007
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Sowing
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Weed & Pest
control
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Harvesting
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What helped to increase Sri Lanka’s paddy
production by a factor of 2.6 during 1952 to 2006?
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between 1960 and 2000: – world population doubled from 3 to 6 billion people
– global economy increased more than sixfold
to meet this demand:– food production increased 2 ½ times
– water use doubled
– wood harvests for pulp and paper production tripled
– timber production increased by more than half
http://www.millenniumassessment.org/
Take a look at the Global Agriculture
Who is eating?
R. Shanthini 07 Jan 2012
Population Undernourished (% of total population)
1990s 2000s
High Human Development
Medium Human Development 20 16
Low Human Development 36 34
High Income
Middle Income
Low Income
World
HDR2007/2008
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Population Undernourished (% of total population)
1990s 2000s
High Human Development
Medium Human Development 20 16
Low Human Development 36 34
High Income
Middle Income 14 11
Low Income 28 24
World
HDR2007/2008
R. Shanthini 07 Jan 2012 HDR2007/2008
Population Undernourished (% of total population)
1990s 2000s
High Human Development
Medium Human Development 20 16
Low Human Development 36 34
High Income
Middle Income 14 11
Low Income 28 24
World 20 17
R. Shanthini 07 Jan 2012 http://www.who.int/mediacentre/factsheets/fs311/en/index.html
Population Overweight(% of total population)
World Data Table is under construction By World Health Organizations
Body Mass Index (BMI) =
Overweight Pre-obese Obese
BMI ≥ 25.00BMI =
25.00 - 29.99BMI ≥ 30.00
weight (in kg)
height2 (in m2)
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BMI (in kg / m2) > 30
30 to 40%20 to 30%10 to 20%5 to 10%0 to 5%No data
Obese adults in population (%)
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– Food production has more than doubled since 1960
– Food production per capita has grown
– Food price has fallen
– Undernourished in developing countries have fallen
Source: http://www.millenniumassessment.org/
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It is good to have increased the food production which might have helped reducing
the number of undernourished people.
The first of the Millennium Development Goals (MDGs) is to
Eradicate Extreme Poverty and Hunger
The seventh of the MDGs is to Ensure Environmental Sustainability
How to achieve both the goals simultaneously?
R. Shanthini 07 Jan 2012
Green Revolution of the 20th century
- transformed agriculture that led (in some places) to significant increases in agricultural production (between the 1940s and 1960s).
- made food production to match with the global population growth.
- has had major social and ecological impacts.
Medieval Green Revolution or the Arab Agricultural Revolution of the 8th century
Source: http://en.wikipedia.org/wiki/Green_Revolution
Green Revolution:
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President Mahinda Rajapaksa greets Prof. M.S. Swaminathan, who is considered the Father of the Indian Green Revolution.
Green Revolution:
Green Revolution of the 21st century?
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in India
- High-yielding varieties of seeds of wheat, rice, and other grains that had been developed in Mexico and in the Philippines were introduced in India after 1965
- Use of synthetic fertilizers, irrigation and pesticide/ herbicide increased
- Increased production made India self-sufficient in food grains
- Famine in India, once accepted as inevitable, has not returned since the introduction of Green Revolution crops.
Green Revolution:
Source: http://en.wikipedia.org/wiki/Green_Revolution
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Is food production actually related to famine?
Prof. Amartya Sen claimed famines such as the Bengal
Famine of 1943 (about 4 million people died) were not caused by decreases in food supply, but by socioeconomic dynamics and a
failure of public action.
Nobel Prize in Economics (1998)
Economist Peter Bowbrick has accused Sen of misrepresenting historical data, telling outright lies and being wrong on his theory of famines.
Green Revolution:
Source: http://en.wikipedia.org/wiki/Green_Revolution
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- introduced high-yielding varieties of seeds that are often developed elsewhere
- increased the use of pesticide/herbicide which were necessary to limit the high levels of pest damage that inevitably occur in monocultures
- increased the use of synthetic fertilizers
- increased dependence on fossil fuels from which pesticides, herbicides and synthetic fertilizers are produced
- increased the use of irrigation (which has created significant problems of arsenic contamination, salinization, waterlogging, and lowering of water tables in certain areas)- affected both agricultural and wild biodiversities
Green Revolution:
Source: http://en.wikipedia.org/wiki/Green_Revolution
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Socioeconomic impacts
- it required the purchase of fertilisers, irrigation pumps and regular fresh supplies of seed
- smaller farmers often went into debt, which in many cases result in a loss of their farmland
Green Revolution:
Source: http://en.wikipedia.org/wiki/Green_Revolution
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A country could go from importing food to exporting it
seen by some as committing ecological and economic "suicide"
Green Revolution:
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Growing crops need carbon (C), hydrogen (H), oxygen (O), energy, and other nutrients
Fertilizer Use:
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Air gives C as CO2; O as O2; H as water vapour Water gives HSunlight gives energySoil gives other essential nutrients
Major nutrients:
Nitrogen (N) Phosphorus (P) Potassium (K) Sulphur (S)Calcium (Ca) Magnesium (Mg)
Minor nutrients:Iron (Fe)
Molybdenum (Mo)Boron (B)
Copper (Cu)Manganese (Mn)
Zinc (Zn)Chlorine (Cl)and others…
Fertilizer Use:
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Fertilizers are chemicals that supply plant nutrients, mostly N, P and K.
With high yielding varieties of crops, most soils are unable to supply the needed amounts of plant nutrients.
Fertilizer Use:
Manufacture of N-based synthetic fertilizers requires fossil fuels as raw materials.
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Source: http://www.allrefer.com/pictures/s4/p0001901-nitrogen-cycle
Fertilizer Use: Nitrogen cycle
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Nitrogen fertilizer
producing factory
Nitrogen cycleFertilizer Use:
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Fossil fuels
Nitrogen fixations in agroecosystems
Fertilizers and industrial uses
Total human input
Projected human input
Teragrams of nitrogen per
year
Fertilizer Use:
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Nitrogen-based fertilizers can be washed from the fields into rivers and streams.
Excessive amount of nitrogen in the water could cause algal blooms that leads to eutrophication and other harms.
Fertilizer Use:
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Fertilizer run-off Eutrophication
3. Aquatic plants begin to die
4. Dead matter feeds the microbes
1. Algae grow fast, using up lots of dissolved oxygen in water.
2. Algae block sunlight
Source: http://www.bbc.co.uk/gcsebitesize
5. Microbes compete for dissolved oxygen
6. Water looses dissolved oxygen
7. Fish die
Fertilizer Use:
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inTaihu Lake, China
Algal bloom in real life
in Great Lakes,
USA
Fertilizer Use:
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“Red tide” of the dinoflagellate Noctiluca stretched for more than
20 miles along the southern California
coast.
Algal bloom in real lifeFertilizer Use:
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Phaeocystis boom lead to foam formation that accumulate on nearby
coastal areas in the North Sea
Algal bloom in real lifeFertilizer Use:
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Use of fertilizers has positive effects on the economic and the social components of sustainable development?
Fertilizer Use:
It has negative effect on the ecological component?
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Harmful algal blooms (HABs) could produce toxins that accumulates in shellfish that consume algae.
Health of the public that consume the shellfish is at risk.
Affected areas should be closed and get closed (in the west).
No fishing. Fishermen are affected. Economy is affected.
Algal bloom in real lifeFertilizer Use:
Source: http://www.whoi.edu/redtide/page.do?pid=9257#
What abut the economic and the social components of SD?
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Researchers are investigating the use of natural clays in Florida’s Sarasota Bay as a potential tool to mitigate harmful algal blooms, or “red tide”.
Source: http://www.whoi.edu/redtide/page.do?pid=9257#
Algal bloom in real lifeFertilizer Use:
What abut the economic component of SD?
R. Shanthini 07 Jan 2012
Fertilizer Use: Ways to Minimize Fertilizer Impact
It is not growing the same crop at the same plot of land throughout the year.
Soil fertility: Different crops have different soil requirements and benefits. Changing crops from year to year minimises deficiencies and allows the soil to replenish.
Soil structure: Alternating between deep-rooted and fibrous-rooted crops improves soil structure.
Source: http://www.rhs.org.uk/advice/profiles1200/crop_rotation.asp
Crop rotation (or sequencing)
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Fertilizer Use: Ways to Minimize Fertilizer Impact
Source: http://www.rhs.org.uk/advice/profiles1200/crop_rotation.asp
Crop rotation (or sequencing) Examples Soil requirements Soil benefits
Cabbage Cauliflower
nitrogen-rich soil; may need liming
Legumes (Pea, bean)
well-drained; moisture-retentive;
not nitrogen-rich
Fix atmospheric nitrogen in roots for
future crops
Onion, Garlic Leek
high organic matter; may need liming
PotatoTomato
high organic matter and nitrogen (potato); no lime
Suppress weeds, break up soil structure
CarrotCelery
not freshly manured Root crops break up soil structure
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Fertilizer Use: Ways to Minimize Fertilizer Impact
An example:
Nitrogen fixing symbiotic systems such as Sesbania rostrate Azolla and free-living cyanobacteria to rice crop
Source: http://www.rhs.org.uk/advice/profiles1200/crop_rotation.asp
Biofertilizers
R. Shanthini 07 Jan 2012 Source: http://www.ecifm.rdg.ac.uk/pesticides.htm
Pesticide Use: Fate of pesticides in the environment
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Fate of pesticide in the environment is determined by its characteristics, such as
• water solubility:measures how easily a pesticide may be washed off the crop, leach into the soil or move with surface runoff.
• soil adsorption: tendency of pesticides to be attached to soil
particles
• half-life: pesticide persistence in the environment (or the time in days required for a pesticide to degrade in soil to one-half its original amount)
http://www.agf.gov.bc.ca/pesticides/c_2.htm
Pesticide Use:
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http://www.agf.gov.bc.ca/pesticides/c_2.htm
Pesticide Use:
Water solubility
Soil adsorption
Half-life Fate of pesticide
high low Long
(more than 21 days)
Move into water
low very high Strongly attached
to soil
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The purpose of using pesticides / herbicides is to kill.
They could kill not only pests and weeds (which they are supposed to) they could also kill and harm beneficial organisms and plants.
DDT, a compound found in pesticides, had worked its way up the food chain, bioaccumulating or increasing in concentration at every level until it was enough to weaken the shells of eagle eggs.
Pesticide Use:
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Crop Rotation (or Crop Sequencing)
Pest and disease control: Soil pests and diseases tend to attack specific plant families, so by rotating crops the pests' life-cycles are broken and build-up is reduced.
Weed control: Some crops (e.g. potatoes) can suppress weeds, minimising problems for following crops.
Ways to Minimize Pesticide Impact
Pesticide Use:
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Crop Rotation (or Crop Sequencing)
Farmers in Matale district rotate tomato with paddy.
The crop is planted in Yala (dry season) followed by paddy in the Maha (wet season)
P. Solanacearum which causes bacterial wilt in tomato is unable to live under anaerobic conditions. Hence six months rotation is effective in controlling the disease.
Ways to Minimize Pesticide Impact
Pesticide Use:
Dr. C. Kudagamage Deputy Director (Research) Horticultural Crop Research & Development Institute Gannoruwa, Peradeniya
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Integrated Pest Management (IPM)
IPM doesn't rely solely on chemicals for pest control.
Biological control, cultural practices, and timely chemical applications are used to obtain the necessary level of control.
Pesticides are the last line of defence and are used only when pest levels are causing sufficient damage to offset the expense of the application.
http://www.agf.gov.bc.ca/pesticides/c_2.htm
Ways to Minimize Pesticide Impact
Pesticide Use:
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http://www.agf.gov.bc.ca/pesticides/c_2.htm
Ways to Minimize Pesticide Impact
Pesticide Use:
Native Plants Garden
Planned for NO use of herbicides / pesticides
Weeds removed by hand
Choose plants that grow quite densely, leaving little room for weeds once they are established
Tolerate many insects as part of the garden's mini-ecosystems (caterpillars bring birds to the garden!)
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