Agriculture: Our Relationship with the Land (Cached)

Session 08

ES/SO352 Sustainability - Session 08

S8: Agriculture: Our Relationship with the Land

Required readings:



  • Identify the negative side effects of some agricultural practices in our environment (air, land, water).
  • Learn about the green revolution and the new attempts to boost productivity with a new series of risky practices
  • Learn the short and long proven effects, as well as potential risks, to natural health with the use of Genetically Modified Organisms (GMO)
  • Learn the importance of preserving top soils for agriculture
  • Learn the concepts Bioaccumulation, Biomagnification, Eutrophication.

1. Introduction


2. Agricultural Land


3. The Green Revolution

"The Story of English wheat is typical:
* It took nearly 1.000 years for wheat yields to increase from 0.5 to 2 metric tons per hectare, but only 40 years to climb from 2 to 6 metric tons per hectare.
* Modern plant breeding, improved agronomy, and the development of inorganic fertilizers and modern pesticides fueled these advances"

From IFPRI, 2002. Green Revolution: Curse or Blessing?

4. The Green Revolution...


5. ...but it's tapering off


6. ...And we expect we'll need even more


7. Impacts on the environment

1. Pollution
2. Land degradation
3. Overextraction of groundwater (missmanagement of water)
4. Decrease of diversity

Impacts on the environment (1)

  • 1. Pollution
    • Atmosphere
      • CO2, CH4, N2O, NxOx, NH3/NH4+ => Greenhouse effect.
    • Water
      • Eutrophication (due to N & P increase) => Water quality decrease. Death of organisms
      • Pesticides and Herbicides on water => Toxicity to organisms.
        • BioMagnification
        • Bioaccumulation
      • Groundwater contamination => Decrease of water availability; threats to human health.



N increase in river mouths


Eutrophication & Dead zones


Some solutions to N increase & Eutrophication

  1. Reduce use of fertilizers: adoption of No Till/Conservation Agriculture methods
  2. Increase efficiency of fertilizers (slow-release fertilizers)
  3. Less polluting fertilizers
  4. Use Nutrient Budget Approach (use what you need method)
  5. Creation of Advisory Services (to help in best practices application)

Bioaccumulation and Biomagnification

  • Bioaccumulation: through the entire life of an organism (within one species, and of course, trophic level)
  • Biomagnification: through the process of going up in the trophic web, from primary producers of organic matter, up to top predators.

Impacts on the environment (2)

  • 2. Land degradation
    • Soil Erosion (field tillage)
    • Desertification (overgrazing, soil erosion)
    • Impoverished soils (intensive growing, use of mineral fertilizers, tillage)
    • Nutrient cycle alterations (increased N & P concentrations in soils)
    • Salinization & Water logging (excess of water use)

Impacts on the environment (3)

  • 3. Overextraction of groundwater (missmanagement of water)
    • decrease on groundwater levels
    • drying of fossil aquifers
    • soil salinization
    • land subsidence

Impacts on the environment (4)

  • 4. Decrease of diversity
    • reclamation of wetlands
    • generalized use of pesticides and herbicides (affecting margins of field crops)
    • overgrazing

8. Energy and food miles


9. Top Soil Erosion: problem

  • It takes 500 years to replace 1 inch of top soil
    • In a natural environment, top soil is build up by decaying plant matter and weathering rock, and it is protected from erosion by growing plants.
    • In soil made susceptible by agriculture, erosion is reducing productivity up to 65% each year. Former prairie lands, which constitute the bread basket of the United States, have lost one half of their topsoil after farming for about 100 years.
    • This soil is eroding 30 times faster than the natural formation rate.
  • Food crops are much hungrier than the natural grasses that once covered the Great Plains. As a result, the remaining topsoil is increasingly depleted of nutrients.
  • Soil erosion and mineral depletion removes about $20 billion worth of plant nutrients from U.S. agricultural soils every year.
  • Much of the soil in the Great Plains is little more than a sponge into which we must pour hydrocarbon-based fertilizers in order to produce crops..”
    Pfeiifer, 2003, Eating Fossil Fuels

10. Top Soil Erosion: some solutions

  • Adoption of No Till/Conservation Agriculture Methods
  • Grass-strips protection
  • Well-terraced lands

11. Livestock

“The total area occupied by grazing is equivalent to 26 percent of the ice-free terrestrial of the planet.
In addition, the total area dedicated to feed-crop production amounts to 33 percent of total arable land.
In all, livestock production accounts for 70 percent of all agricultural land and 30 percent of the land surface of the planet.”
FAO, 2006, Livestock’s Long Shadow
  • Effect on environment will also depend on what we eat
  • There is a trend towards intensive livestock operations that decreases environmental pressures like overgrazing...

12. Genetically Modified Organisms (GMO)


13. The future of food.

    • Part 1. 9:49'
      {youtube movie=jNezTsrCY0Q" allowFullScreen="y" width="425" height="344"}

14. Why Genetically Engineered Foods Should be Labeled: Gary Hirshberg at TEDxManhattan 2013 (13')

Gary Hirshberg is Chairman of Stonyfield Farm, the world's leading organic yogurt producer, and Managing Director of Stonyfield Europe, with organic brands in Ireland, and France. Gary serves on several corporate and non-profit boards including Applegate Farms, Honest Tea, Peak Organic Brewing, Late July, The Full Yield, SweetGreen, RAMp Sports, Glenisk, the Danone Communities Fund and the Danone Livelihoods Fund. He is the Chairman, CEO and Co-founder of Chelsea's Table Cafés, a natural and organic fast casual restaurant firm. In 2011, President Obama appointed Gary to serve on the Advisory Committee for Trade Policy and Negotiations. He is a Co-Chair of AGree, an agricultural policy initiative formed by the Ford, Gates, Kellogg, Rockefeller, Walton and other leading foundations. He is Chairman and a founding Partner of Just Label It, We Have the Right to Know, the national campaign to label genetically engineered foods, and is co-author of Label It Now - What You Need to Know About Genetically Engineered Foods. He is the author of Stirring It Up: How to Make Money and Save the World.

15. [Animation] Engineer a crop: Transgenic manipulation


16. Latest news about GMO & Health

  • Séralini, G.-E., et al. Long term toxicity of a Roundup herbicide and a Roundup-tolerant genetically modified maize. Food Chem. Toxicol. (2012), http://dx.doi.org/10.1016/j.fct.2012.08.005 Retracted, by Journal editors, but republished by authors elsewhere:
    • Republished study: Séralini, G.-E., et al. Long term toxicity of a Roundup herbicide and a Roundup-tolerant genetically modified maize. Environmental Sciences Europe (2014), 26:14 doi:10.1186/s12302-014-0014-5

17. Other interesting infos

Biochar - Agrichar - Terra Preta. 10:51'

Organic matter from pyrolisis to improve fertility of poor soils & sequester C.
Soil Erosion (demo). 11'

Fun: Grocery Store Wars (2005) 5:51'

Not long ago in a supermarket not so far away.... Help fight the dark side of the farm

Seeds: The Buried Beginnings of Food: Simran Sethi at TEDxManhattan (12:44')


Farmhack - An Open Source Community for Resilient Agriculture (3:18'')

More information: http://sustainablefoodtrust.org/articles/farm-hack/
  • Norse, David (2003). Agriculture and the Environment: Changing Pressures, Solutions and Trade-offs. In Bruinsma, J. (ed.) World Agriculture: Towards 2015/2030 - An FAO Perspective: 331-356 Earthscan, London. ftp://ftp.fao.org/docrep/fao/005/y4252E/y4252e12.pdf

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