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IAPRS & SIS, Vol.34, Part 7, “Resource and Environmental Monitoring”, Hyderabad, India, 2002 
RESULTS AND DISCUSSION 
Visual interpretation: The study area comprised of Basalt and 
Granite landscape with intrusions of dolorite dyke and Quartz 
reef in the granite terrain. Fifteen physiographic and soil units 
were identified (Table-1- Legend). Major soils in the area 
were found to be Rhodustalfs, Udic, Haplustalfs, Typic/Entic 
Chromusterts, Typica ustorthents and Typic ustochrepts. Thirty 
five, Fifty five and Ten percent of soils were identified to be 
subjected to slight, moderate and severe erosion respectively. 
The soils are generally moderately well drained, except in 
broad valley fills where inadequate drainage conditions prevail 
due to flat relief position. The Granitic hills are however 
excessively drained. Soil slope is 0-11% in the valley fills, and 
15-33% in the pediplain and 15-33% in the hills. Soil depth is a 
constraint in the hilly tract as well as in the crest portion of 
pediplain where the soils are young, without any horizonation 
and they are classified as Typic Ustortants. 
Based on the profile and site characteristics and the climate of 
the area, the soils were grouped under land capability class II to 
IV(65%) and VI to VIII(35%). The course textured shallow 
soils in granitic pediplain could not be separated due to the lack 
of tonal variations. These lands were categorized as the VI and 
kept associated as the class IV land in the same unit. 
CLASSES II to IV lands is suitable for agriculture and 
horticulture, whereas VI and VII are suitable for pastures, 
silvipasture, rain-fed horticulture and forestry. Class VIII land 
was found to be meager in extent (less than 1%), which is an 
uncultivable waste. 
Digital analysis: the study area could be classified into four 
categories in respect of soils (Table-2-Legend) as against 
Table-2-Legend 
  
  
  
  
  
  
  
  
  
  
Chromusterts 
Udic 10000 41 
Rhodustalfs; 
Udic haplustalfs 
  
  
  
  
  
  
Water bodies 300 1 
Vegetation 3400 14 
Total 24000 100 
  
  
  
fifteen units by visual interpretation at 1:50,000 scale. 
Vegetation in the hills and reserve forest area hampered the soil 
classification, which covered around 15% of the area. 
Remarkable findings in the digital analysis were the finer 
separability of chromustats in basalt landscape, which are 
visually inseparable. Similarly the shallow eroded patches of 
granitic pediplane were classified separately from the deep, 
moderately eroded pediplan. 
Spectral response of soil and land features: spectral 
response of different soils (Table- 3- Soils & Site 
Characteristics) illustrate that maximum reflection comes 
from Ustorthents and minimum from Chromusterts which is in 
accordance with the established soil spectral response curves. 
Evaluation of different band combination and image 
enhancement techniques revealed that in general stand and 
False Colour Composit (FCC) gives maximum separability of 
different land features. Different images enhancement 
techniques were also found to be very useful in improving the 
image characteristics (Table-4 Land Feature as Depicted in 
Satellite Data). 
Conclusion: Visual interpretations of Satellite data is a reliable 
technique for soil survey but for the limitation that the 
Ustorthents/Ustochrepts developed at the Crest portion of the 
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
Soil Total Area Percentage inter-flows of granitic terrain -are not separable due to poor 
(ha) tonal contrast with adjacent Haphisltalfs and Chodustalfs. As 
Typic 1500 6 against this, by digital analysis the shallow, eroded (sheet 
Ustorthents erosion) Ustorthents could be separated from other soils. The 
Typic 8000 34 effectiveness con however be quantified by comparing the 
Ustochrepts output with a detailed soil survey map. 
Typic 800 4 
Table-1-Legend 
Mapping Physiography Image characteristics Soils 
unit 
H Hills - 
Hl Granitic Hills Brown, coarse texture Loamy skeletal typic Ustorthents 
H2 Bsaalt-Mesa - 
H21 Mesa-top Dark brown, fine texture Fine Typic Chromusterts 
H22 Mesa-periphel slope Light brown, medium texture | Fine Typic Ustorthents 
H3 Dolerite dyke Linear (WE) dark brown Clayey skeletal Typic Ustorthents 
structure 
H4 Quartz reef Linear (NS) light brown Loamy skeletal Typic Ustrothents 
structure 
P Pediplain - - 
Pl Basalt-Moderately eroded | Dark brown, fine texture Fine Typic Chromusterts 
P2 Basalt-Severely eroded Light brown, medium texture | Fine Typic Ustochrepta 
P3 Granitic-Moderately Yellow with few grey Fine loamy Udic Rhodustalfs, 
eroded mottles Fine loamy Udic Haplustalfs 
P4 Granitic-Severely eroded Grey with few yellow Coarse loamy Typic Ustrothents, 
mottles Loamy skeletal Udic Ustochrepts 
V Valley fills - Fine loamy Typic Haplustalfa 
V1 Narrow (<10 mm wide) Light brown with red mottles | Fine loamy Typic Ustifluvents 
V2 Broad (210 mm wide) Brown with red mottles Fine entice Chromusterts 
  
  
  
  
  
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