| (Fig. 2) increases 
100 nm, 40 per cent 
m. The maximum 
it reached to almost 
ly concave between 
n 600 to 1200 and 
1. The prominent 
)0 and 1275 nm. 
ark grayish brown 
? M) sandy loam at 
> andukeshwar 
“haukori 
? ithoragarh 
  
  
  
1.5 1.8 
  
titude soils 
hill terraces under 
under coarse-loamy 
idolls.The spectral 
creases from 4 per 
per cent at 900 nm 
im reflectance was 
ilmost 48 per cent. 
350 to 900 nm and 
ly convex between 
of the soils showed 
0 nm. 
p, brown (10YR4/3 ' 
rface, well drained, 
of hill slopes under 
fine-loamy, mixed, 
1 (Fig. 2) increased 
500 nm, 30 per cent 
m. The maximum 
20 nm. The spectral 
ption bands at 950 
band at 750 nm 
very dark grayish 
ngly acid (pH 5.2) 
re. These soils are 
ly of Humic Lithic 
eases from about 4 
, 30 per cent at 900 
nm and 40 per cent at 1200 nm. The maximum soil reflectance 
was noticed at 1700 nm where it reached to 50 per cent. The 
shape of the curve was slightly concave between 350 to 600 nm 
and almost linear between 600 and 1200 nm and slightly 
convex between 1500 to 1800 nm. Three prominent absorption 
bands at 750, 950 and 1100 nm were noticed. 
Malari soils: Soils are deep to very deep with increasing 
gravel content, well drained, reddish yellow (7.5YR 6/6 D) 
sandy loamy at surface, slightly acid (pH 6.3), occurring on 
terraces of high hill slopes. These soils qualify for loamy- 
skeletal, mixed, mesic, Typic Eutrudepts soil family. The 
reflectance from Malari soil (Fig. 3) increases from 4 per cent 
at 350 nm to 25 per cent at 600 nm, 38 per cent at 900 nm and 
47 per cent at 1200 nm. 
  
  
60 
Un 
eo 
1 
a 
    
A 
© 
1 
  
Reflectance (%) 
  
  
  
  
  
  
03 0.6 0.9 12 L5 18 
Wavelength (um) 
  
  
  
Figure 3. Spectral curves of high altitude soils 
The maximum reflectance of 54 per cent was recorded at 1700 
nm. The shape of the curve was concave between 350 to 600 
nm, convex between 600 to 900 nm, almost linear between 900 
and 1500 nm and convex between 1500 to 1800 nm. Four 
prominent absorption bands at 750, 950, 1100 and 1275nm 
were noticed on the spectral curve. 
Badrinath soils: Soils are moderately deep with high amount 
of stones in sub-surface horizons, well drained, brown 
(10YR4/3 D&M) sandy loam at surface, slightly acid (pH 6.1) 
IAPRS & SIS, Vol.34, Part 7, “Resource and Environmental Monitoring", Hyderabad, India,2002 
occurring on terraces of high hill slopes. These soils are 
classified as loamy-skeletal, mixed, mesic family of Lithic 
Udorthents. 
The reflectance from Badrinath soil ( Fig. 3) increases from 2 
per cent at 350 nm to 11 per cent at 600 nm, 28 per cent at 900 
nm and 40 per cent at 1200 nm. The maximum reflectance was 
recorded at 1700 nm where it reached to about 50 per cent. The 
shape of the curve is slightly concave between 350 to 600 nm, 
linearly straight between 600 to 900 nm, slightly convex 
between 900 to 1200 nm region and convex between 1500 and 
1800 nm. Four prominent absorption at 750, 950, 1100 and 
1275 nm wavelength were noticed. 
Shelang soils: Soils are deep, moderately well drained, very 
dark grayish brown (10YR 3/2 D&M) loam at surface, strongly 
acid (pH 5.2) occurring on northern aspect of high hill slopes 
under Moru forest. These soils are classified as fine-loamy, 
mixed, mesic, family of Typic Hapludolls.The reflectance from 
Shelang soil (Fig. 3) increases from 2 per cent at 350 nm to 8 
per cent at 600 nm, 22 per cent at 900 nm and 30 per cent at 
1200 nm. The maximum reflectance was recorded at 1700 nm 
where it reached to about 35 per cent. The shape of the curve is 
concave between 350-600 nm, almost linear between 600-900 
nm and slightly convex between 900-1800 nm. 
3.6 Soil colour vs soil reflectance 
Colour is one of the important characteristics of the soils. It 
indicates the fertility status and drainage condition of the soils. 
Munsell colour notation and corresponding RGB values of 
different soils are given in table 5. Soil colour, particularly the 
Munsell color value component, has been identified in many 
studies affecting the amount of energy reflected from soil 
surface (Condit, 1970; Post et al, 1994). The observed 
darkening of wet soil is due to the optical effects of a thin liquid 
layer on the soil surface (Post et al., 2000). The visible (0.4-0.7 
um) region has been widely used for color determinations in 
soils as well as in the identification of Fe oxides and hydroxides 
(Ben-Dor et al, 1999). Unlike the Munsell System, RGB 
coordinates express the red, green and blue component of a 
given colour. 
Table 5. Munsell colour notation, RGB values and spectral reflectance of soil in visible region as influence by organic and iron 
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
content 
Soils Colour (D) | R G B Spectral readings (Dry O.C. Total (%) Free 
soil) (%) Fe,03 
Red Green | Blue FeO Fe,03 (%) 
(625- (525- | (450- 
700 600 525 
nm) nm) nm) 
Karan Prayag 25Y 572 132 {120 11/099 2121 16.5 12.6 2.07 0.9 1.8 0.4 
Baijnath 10YR 5/3 140-.| 118: | 91 25.6 18.7 12.3 1.04 0.7 1.6 0.5 
Mahergaon 2.5Y 6/4 166 | 145 | 100 | 21.2 16.2 11.2 3.0 3.1 3.6 1.2 
Pithoragarh 2.5Y 6/6 174 143^ 175 29.6 22.1 14.7 1.47 0.2 3.0 2.4 
Pandukeshwar 10YR 4/2 110 | 94 76 13.6 9.6 7.1 5.76 0.7 11 0.6 
Chaukori 2.5Y 6/4 166 | 145 | 100 | 18.6 12.9 8.9 3.98 0.4 2.4 0.9 
Auli 2.5Y 5/3 137 | 120 | 88 19.6 14.2 9.9 4.06 LA 2.9 1.5 
Malari 7.5 YR6/6 186 | 138 | 88 29.5 19.4 10.6 0.92 0.9 2.0 1.4 
Badrinath ' 10YR 4/3 115 193 67 13.9 9.2 6.3 3.69 0.9 2.9 1.3 
Shelang 10YR 3/2 85 71 56 10.8 7.2 5.2 8.32 LA] 2.3 13