37 
ISSUES IN SOILS / LAND DEGRADATION 
MAPPING 
Because of the importance of soil information in 
both agriculture and non-agriculture sectors develop 
ment and considering the entire scenario of availability 
of soil maps in India, there is a need to take stock of 
various activities connected with generating soil 
information and plan for national level soil information 
system. Though soil maps are available at 1:250,000 
scale for the whole country (NBSS & LUP) they serve 
the requirement of broad land use planning at 
regional/state level. In recent years for many of the 
projects concerned with conservation of natural 
resources or for planning the strategies to combat land 
degradation or to develop action plans to improve land 
productivity the emphasis is on soil information at 
1:50,000 scale especially for district level planning. 
Though soil information is generated at 1:50,000 scale 
on a limited scale either by NBSS &LUP or AÏS & LUS 
or under 1MSD programme by DOS, there is a need for 
generation of soil resources information nationwide at 
1:50,000. 
The soil resources mapping in our country is being 
carried out by various central and state government 
organisations and there is no regular system of recording 
and updating of the areas covered by soil surveys. 
Moreover, soil surveys done by various institutes lack 
uniformity with respect to scale of mapping and 
publishing, objectives of surveys, kind of survey and 
intensity of observations, level of interpretation etc. 
These are essential to maintain accuracy of soil mapping 
and also to create a uniform data base on soils for entire 
country for better landuse planning. Some of the key 
issues are discussed below : 
Standardization of methodology for large scale soil 
mapping 
In recent years all soil survey organisations in the 
country are using satellite imagery as base material to 
conduct standard soil surveys. In order to achieve 
required accuracy level at 1:50,000 mapping scale, the 
methodology using satellite data need to be standardized 
with respect to size of sample strips, number of profile 
observations in the field and level of soil classification. 
This can be achieved through formation of a national 
level committee consisting of soil experts from all Soil 
Survey Organisations. Preparation of training manual for 
standardized methodology with appropriate legend is 
essential and subsequently manpower of various 
institutes should be given training. 
Quality Audit 
In order to have an uniform soil data base for the 
whole country at 1:50,000 scale, the existing soil maps 
at 1:50,000 scale with various organisations need to be 
checked for quality by an expert committee before using 
them to create data base. Guidelines for quality auditing 
of soil maps should be formulated in consultation with 
various state/central government organisations. Even for 
the mapping to be done in future, quality of delineation, 
interpretation of remote sensing data, ground truth 
collection and soil chemical/physical analysis etc. has to 
be thoroughly standardised. 
Digital Data Base 
There is an immediate need for comprehensive 
nation-wide data base creation for voluminous data 
generated through soil surveys by various organisations 
for soil maps (spatial data base) and attribute data (e.g. 
soil physical and chemical properties, climatic data, 
etc.). This enables to carry out integrated analysis of soil 
resources data for formulating strategies for the 
development of agricultural and non-agricultural sectors. 
This calls for the design of a sound data base using 
Geographical Information System (GIS) for storage, 
updation, retrieval, analysis and generation of outputs. 
Though various soil survey organizations have 
developed their own data base, a national level facility 
should be made to standardize the various aspects of 
creating digital base such as design, coding, GIS 
package to be used etc. 
Mapping and monitoring of degraded lands 
There is a need to prepare inventory on degraded 
lands using geocoded satellite data at 1:50.000 scale as 
the estimates of degraded land by various organizations 
varies from 53 million hectares to 187 million hectares. 
This information is very essential to plan strategies for 
reclamation/conservation of degraded lands which result 
in bringing additional areas into cultivation and also to 
improve productivity levels in marginal lands. 
Monitoring of degraded lands in subsequent years is 
important at an interval of 5-10 years using satellite data 
base to know the impact of reclamation and conservation 
programmes. 
CONCLUSION 
Remotely sensed data from space borne sensors are 
very valuable tools in the preparation of accurate soil 
and land degradation maps in time and cost effective 
way at different scales. By considering various aspects 
of soil mapping especially for district level planning, 
1:50,000 scale appears to be optimum for National level 
inventory on soil resources. Moreover, the topo base for 
the entire country is available at 1:50,000 scale, which 
also indicates the largest scale of soils and land 
degradation mapping that could be planned at present is