R. Shanthini 07 Jan 2012 “In the end we will conserve only what we love; we will love only what we...

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


Module 8:

Use of fertilizers and pesticides, green revolution,

and agricultural biotechnology in the agricultural sector,

and their impact on sustainable development.


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


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


Ploughing

in 2007


Sowing


Weed & Pest

control


Harvesting


What helped to increase Sri Lanka’s paddy

production by a factor of 2.6 during 1952 to 2006?


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?


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



1990s 2000s




High Income

Middle Income 14 11

Low Income 28 24

World

HDR2007/2008

R. Shanthini 07 Jan 2012 HDR2007/2008


1990s 2000s




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)


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 (%)


– 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/


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?


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:


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?


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:



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:



- 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:



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:



A country could go from importing food to exporting it

seen by some as committing ecological and economic "suicide"

Green Revolution:


Growing crops need carbon (C), hydrogen (H), oxygen (O), energy, and other nutrients

Fertilizer Use:


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:


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.


Source: http://www.allrefer.com/pictures/s4/p0001901-nitrogen-cycle

Fertilizer Use: Nitrogen cycle


Nitrogen fertilizer

producing factory

Nitrogen cycleFertilizer Use:


Fossil fuels

Nitrogen fixations in agroecosystems

Fertilizers and industrial uses

Total human input

Projected human input

Teragrams of nitrogen per

year

Fertilizer Use:


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:


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:


inTaihu Lake, China

Algal bloom in real life

in Great Lakes,

USA

Fertilizer Use:


“Red tide” of the dinoflagellate Noctiluca stretched for more than

20 miles along the southern California

coast.

Algal bloom in real lifeFertilizer Use:


Phaeocystis boom lead to foam formation that accumulate on nearby

coastal areas in the North Sea



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?


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.


Source: http://www.whoi.edu/redtide/page.do?pid=9257#

What abut the economic and the social components of SD?


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#


What abut the economic component of SD?


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)




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



An example:

Nitrogen fixing symbiotic systems such as Sesbania rostrate Azolla and free-living cyanobacteria to rice crop


Biofertilizers

R. Shanthini 07 Jan 2012 Source: http://www.ecifm.rdg.ac.uk/pesticides.htm

Pesticide Use: Fate of pesticides in the environment


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:



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


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:


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:


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.


Pesticide Use:

Dr. C. Kudagamage Deputy Director (Research) Horticultural Crop Research & Development Institute Gannoruwa, Peradeniya


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.



Pesticide Use:




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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