Desertification

The nutrition needs of the future will be met with more limitations than in the past on the use of energy and restrictions on contamination of the environment. The maintenance of natural resources will receive much more attention than in the past. Concerns will increase regarding desertification, deforestation, urbanization, salinification, soil and water degradation, and atmospheric pollution. There is considerable difficulty in delineating these limitations, particularly as one considers the responsibilities and interests of developed and developing countries. The role of economics offers an additional challenge in working out these relationships. 

The exposure of calcium carbonate soils by erosion in early stages of desertification may contribute to the paucity of available nitrogen by ammonium volatilization. In soils of high pH, ammonium is converted to NH3 which is lost to the atmosphere by ... 

United Nations. 1978. United Nations Conference on Desertification... 

Dregne, H.E. Desertification of Arid Lands. Harwood Academic Publishers. New York. 1983. 

Hydrological Studies to predict Water Supply and Flood Protection Needs, and to Avoid exacerbating water problems with Poorly Conceived Solutions (e.g. desertification in one area caused by channeling water to irrigate another—such as in Iran or flooding worsened downstream in urban areas by dykes protecting farmland—like Poland s 1997 flood). 

Climate Change and its Worse Effects such as Erosion and Desertification. 

Containment of Desertification by Irrigation, Limiting Grazing, and Planting Grasses and Bushes that Hold the Soil. 

An aridity definition that takes account of the relation precipitation/potential evaporation is the Aridity Index used in the Atlas of Desertification (UNEP, 1993). Four different degrees of aridity can be recognized. These are best defined using the Aridity Index (AI), calculated as the ratio P/PET, where P stands for precipitation and PET for (potential) evapotranspiration. AI values of <1.0 indicate an average annual moisture deficit. According to this criterion, four subzones can be discussed ... 

Figure 1.2. Global land area by aridity zone (%) (after UNEP, 1993. Reprinted from World Atlas of Desertification, Figure of global land area by aridity zones, p 5, Copyright (1993), with permission from UNEP)...

UNEP. World Atlas of Desertification. London, New York Edward Arnold, 1993. 

United Nations Environment Programme (UNEP) (1992) World atlas of desertification. Edward Arnold, London... 

Descriptive marks, 25 256-257 Descriptive sampling, 26 1005 Desertification, United Nations program to combat, 24 169... 

Overcultivation Syndrome Overcultivation of marginal land Destabilization of ecosystems, loss of biodiversity, soil degradation, desertification, threats to food security, marginalization, rural exodus... 

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