Topsoil
Posted by edro on February 18, 2008
No Good for Farming!
“A [farmer] took up land [in Saskatchewan], dug a cellar and built a frame house on top of it; ploughed up the prairie and grew wheat and oats. After 20 years he decided the country was no good for farming, for eight feet of his soil had gone and he had to climb up into his house.” —Richard St, Barbe Baker, My Life, My Trees [Quoted by John Jeavons in How to Grow More Vegetables]
Land Use And Topsoil
Once A Forest! Photo credit: UNEP
Topsoil
Measuring an average of about 6.6 inches (16.76 centimeters) deep, topsoil is the upper layer of earth’s crust. Topsoil comprises of a mix of humus, mineral and composted materials giving rise to most of the soil’s biological activity and supplying nutrients to plants and therefore to animals. After air and water, topsoil is Earth’s most vital resource.
Topsoil: Wild Facts
Table TS1. Topsoil: Wild Facts
Note: The average bulk density of topsoil is calculated at about 1.4 gcm-3
Causes of soil degradation
- Soil erosion, salination, deforestation, overexploitation for fuelwood, overgrazing, nutrient depletion, large scale agricultural activities, industrialization and desertification.
- The rate of degradation is increased exponentially against large scale agriculture.
- Severe loss of arable land is affecting our ability to feed the world population.
- Soil degradation is occurring globally, both in poor and wealthy countries.
Land Use and Degradation
Table TS2. Earth: Land use and degradation
Note: The estimates for Biologically Productive Land are from a 2002 FAO report: The State of Food and Agriculture FOOD AND AGRICULTURE ORGANIZATION OF THE UNITED NATIONS Rome, 2005, ISBN 92-5-105349-9
References [accessed February 1-17, 2008]
- http://www.ecostudies.org/reprints/Downing_et_al_2006_Limnol_Ocean.pdf
- http://www.csupomona.edu/~admckettrick/projects/ag101_project/html/destruction.html
- Institut de Recherche Pour le Développement (2008, January 8). Overgrazing Accelerating Soil Erosion In Northern Mexico. ScienceDaily. Retrieved February 15, 2008, from http://www.sciencedaily.com/releases/2008/01/080107110358.htm
- http://www.webofcreation.org/Earth%20Solutions/Land%20Use.htm
- http://www.1world2travel.com/print.php?articleID=2830
- http://sedac.ciesin.columbia.edu/tg/guide_glue.jsp?rd=lu&ds=8
- http://sedac.ciesin.columbia.edu/tg/resources.jsp?rd=lu&ds=8
- http://books.nap.edu/openbook.php?record_id=11991&page=84
- http://hypertextbook.com/facts/
- http://www.fao.org/AG/magazine/9810/spot4.htm
- http://www.webofcreation.org/Earth%20Solutions/Land%20Use.htm
- UNFAO, “Forest Resources Assessment 2000” http://www.fao.org/forestry/fo/fra/index.jsp
- http://www.fao.org/ES/ess/chartroom/default.asp
- http://www.lib.umich.edu/govdocs/wdi/wdivar/wdivar1.html
- http://www.fao.org/docrep/008/a0050e/a0050e10b.htm
- http://assets.panda.org/downloads/wetlandsbrochurefinal.pdf
- http://www.ecostudies.org/reprints/Downing_et_al_2006_Limnol_Ocean.pdf
- http://home.alltel.net/bsundquist1/se4.html
- http://home.alltel.net/bsundquist1/la2.html
- http://home.alltel.net/bsundquist1/la0.html
- “It has been estimated that, today, 83% of the world’s free-ice lands are impacted, directly or indirectly, by humans” [Sanderson E. W., Jaiteh M, Levy M. A., Redford K. H., Wannebo A. V., Woolmer G., “The Human Footprint and the Last of the Wild”. Bioscience 52 (2002)]
EDRO 
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