1. Katherine H. Brown and Ann Carter et al., Urban Agriculture and Community Food Security in the United States: Farming from the City Center to the Urban Fringe, Urban Agriculture
Committee of the Community Food Security Coalition, 2003. www.foodsecurity.org/PrimerCFSCUAC.pdf
2. J. Pretty, J. I. L. Morison and R. E. Hine, "Reducing Food Poverty by Increasing Sustainability in Developing Countries," Agriculture, Ecosystems and Environment, 95, No. 1: 2003 pp. 217-234.
3. ADAS Consulting Ltd., Energy Use in Organic Farming .Systems, Ministry of Agriculture, Fisheries and Food, Project 0F0182, DEFRA, London, 2001.
4. John G.Howe, The End of Fossil Energy and the Last Chance for Sustainability, 2nd ed., Mclntire Publishing Services, 2005. www.mcintirepublishing.com
5. Folke Gunther, Vulnerability in Agriculture: Energy Use, Structure and Energy Futures, presented at the INES Conference, THK, Stockholm, June 15,2000. www.etnhum.etn.lu.se/~fg/written/stuff/ines/INES.pdf
Phosphorus cannot be obtained from the atmosphere by leguminous plants, as is the case with nitrogen. Nor is it as widely available in soils as is potassium, which is supplied by the breakdown of potassium feldspar and various clay minerals. Presently, phosphorus is supplied through the mining of phosphate ores.
Available phosphorus sources may be economically depleted in 130 years at current energy prices. Phosphate ore extraction is an energy-demanding process. Energy depletion may considerably shorten the lifetime of phosphorus mining operations. Incidentally, a valuable amount of phosphates are wasted in detergents and then go unreclaimed through our sewage treatment systems.
10. J. Smit, A. Ratta and J. Nasr, Urban Agriculture: Food, Jobs, and Sustainable Cities, United Nations Development Programme, 1996.
11. United Nations Division for Sustainable Development, Unit ed Nations Sustainable Development Success Stories, Vol. 4.
12. Michael Ableman, "Agriculture's Next Frontier: How Urban Farms Could Feed the World," Utne Reader, November-December 2000.
13. R. Heimlich and C. Bernard, Agricultural Adaptation to Urbanization: Farm Types in the United States Metropolitan Area, Economic Research Service, USDA, 1993.
14. Interpress Service, "Learn from Cuba," Says the World Bank, Mayi, 2001.
15. Lang, Food Safety and Public Health.
16. Giampietro and Pimental, Tightening Conflict.
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