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Application of remote sensing and GIS for sustainable development

L. Venkataratnam
Agriculture & Soils Group
National Remote Sensing Agency, Dept, of Space, Hyderabad
The natural resources of a country are of primary
importance for the development of economic life of its
inhabitants and more specifically the soil resources
because they are non-renewable vital resources for
agricultural production and also for the development of
non-agricultural sectors. The soils are highly vulnerable
to degradation and nature takes very long period (say
300 - 1000 years) to form an inch of the top fertile soil.
Scientific management of soils is essential for the both
continued agricultural productivity and protection of the
environment. A pre-requisite for this is comprehensive
information on soil resources in terms of types of soils,
their spatial distribution, extent, their limitations viz.,
erosion, salinization / alkalization, water logging etc.,
and their potential / capabilities. This information is
needed for a variety of purposes such as optimum land
use planning, command area development, soil
conservation in catchment areas, rainfed farming,
watershed management, reclamation of degraded lands
etc. This requires systematic characterization of soils,
more accurate mapping of soils and developing rational
and scientific criteria for interpretation of soil
information for various land uses. Similarly, the
information on the nature, extent, spatial distribution and
magnitude of land degradation plays a vital role in
planning strategies for reclamation / conservation of
degraded lands.
The soil maps are required on different scales
varying from 1:1 million to 1:4000 to meet the
requirements of planning at various levels (Table 1).
Because the scale of a soil map has direct correlation
with the information content and field investigations that
are carried out. Small scale soil maps of 1:1 million are
needed for macro level planning at National level. The
soil maps at 1:250,000 scale provide information for
planning at regional or state level with generalised
interpretation of soil information for determining the
suitability and limitations for several agricultural and
non-agricultural uses and requires less intensity of soil
observations and time. The soil maps at 1:50,000 scale
where association of soil series are depicted, serve the
purpose for planning resources conservation and
optimum land use at district level and require moderate
intensity of observations in the field. The large scale soil
maps at 1:8,000 or 1:4,000 scale are specific purpose
maps which can be generated through high intensity of
field observations based on maps at 1:50,000 scale or
large scale aerial photographs or very high resolution
satellite data. Similarly, information on degraded lands
like salt affected soils, eroded soils, water logged areas,
jhum lands etc., is required at different scales Re
planning strategies for reclamation and conservation of
degraded lands.
Soil survey programme in India started during pre
independence era and progressed significantly. Soil
surveys are being carried out by various central and state
level organizations. The soil surveys done till 1970 (20%
of the area of the country) lacked correlation, uniform
nomenclature and appropriate soil mapping units with
legends. According to Report of the Task Force (1984)
constituted by the Planning Commission, the total area
surveyed in the country upto 1983 under detailed and
reconnaissance soil surveys are 33.5 and I 15.0 million
hectares, respectively. From late eighties onward, soil
survey and mapping at 1:50,000 scale is being done by
different agencies using satellite data and soil maps are
used as critical input for generating action plans for
development of land and water resources on sustainable
basis. National Bureau of Soil Survey and Land Use
Planning (NBSS & LUP) has prepared soil maps at
1:250,000 scale for the whole country. Approximately
l/3 ,d of the total geographical area of the country is
already mapped at 1:50,000 scale by various organi
zations under different projects. (Table 2) (DOS, 1999)
Efforts are made by various agencies to identify
various types of degraded lands, their spatial extent and
severity levels (Table 3). According to National
Commission on Agriculture (1976) 175 million hectares
of land constituting 53.3 percent of the total geogra
phical area of 329 million hectares are subject to some