Rao, D.P. 
  
  
optimal land use plans/action plans. An attempt has been made in this article to 
provide an overview of the magnitude of the land degradation problem, concepts 
of sustainable development based on conservation of land and water resources 
and to identify sustainability indicators and to illustrate the role of remote 
sensing, GIS, GPS and digital photogrammetry. A few case studies are cited on 
the success stories on sustainable development of land and water resources. 
Furthermore, the article also identifies gap areas, and projects future scenario 
vis-à-vis likely developments in sensor technology, data processing and 
interpretation/analysis and integration. 
1. INTRODUCTION 
Due to ever increasing pressure of population on land, the per capita arable land 
has been dwindling. In the year 1986, the worldwide cropped area was 1.5billion 
ha which was supporting the total world population of about 5 billion. The per 
capita arable land in 1986, thus works out to be 0.3 ha. With the increasing 
population pressure it has been progressively declining. By the year 2000, the 
per capita arable land area will decline to 0.23ha, and to 0.15ha by 2050 (Lal 
and Pierce, 1991).?? The problem of low land-to-people ratio is further 
compounded by land degradation by way of accelerated soil erosion by water 
and wind, salinization and / alkalization, waterlogging, compaction ; mining and 
depletion of organic matter. With only 55 per cent of the geographical area of 
the world, the developing countries carry 75 per cent of the world population 
which leads to over-exploitation of natural resources. 
Globally, 1964.4x10° ha land are affected by human-induced degradation(UNEP, 
1993). Of this, 1,903x10%ha are subject to soil erosion by water, 548.3x10° ha to 
wind erosion, 239.1x10%ha to chemical deterioration, 68.2x109ha to compaction 
and 10.5 x 10fha to waterlogging In addition, an estimated 3,600 million ha of 
global area comprising of hilly regions of the humid tropics of India , Manchurea, 
Korea, south-west China and Africa are under shifting cultivation (Schlippe, 1956; 
Conklin, 1957). In India alone, out of a 329 million ha geographical area, 150 
million ha of land are affected by wind and water erosion (Anonymous, 1976). 
Annually, an estimated 6000 million tonnes of soil in lost through soil erosion by 
water (Das, 1985). Apart from this, shifting cultivation, waterlogging, and 
salinization and / or alkalization have affected an estimated 4.36million ha, 
6million ha and 7.16million ha of land respectively (Anonymous, 1976). Frequent 
floods and drought further compound the problem. Degradation of by way of 
deforestation for timber and fuel wood, shifting cultivation and occasionally 
forest fire is a very serious environmental problem. Besides, another equally 
important aspect of the sustainability of vegetation is the bio-diversity that need 
to be preserved. 
  
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International Archives of Photogrammetry and Remote Sensing. Vol. XXXIII, Part B7. Amsterdam 2000.