| (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