Three spectral models defining the spatial distribution of soil areas by levels of amorphous iron, organic carbon, and the ratio of amorphous iron to organic carbon were developed and field verification studies were conducted. The models used particular Thematic Mapper band ratios selected by statistical correlation with soil chemical data. The ability of the models to indicate erosion severity and to differentiate between iron enriched and carbonate paleosols is discussed. In addition, the effect of vegetation cover on paleosols is addressed

Busacca, Alan

Cheng, Yaan

Frazier, B. E.

Gill, Steve

Hart, Judy

Wherry, David

English

NASA Technical Reports Server

Spectral characteristics and the extent of paleosols of the Palouse formation

Spectral relationships were investigated for several bare soil fields which were in summer fallow rotation on the date of the imagery. Printouts of each band were examined and compared to aerial photography. Bands with dissimilar reflectance patterns for known areas were then combined using ratio techniques which were proven useful in other studies (Williams, 1983). Selected ratios were Thematic Mapper (TM) 1/TM4, TM3/TM4, and TM5/TM4. Cluster analyses and Baysian and Fastclass classifier images were produced using the three ratio images. Plots of cluster analysis outputs revealed distinct groupings of reflectance data representing green crops, ripened crops, soil and green plants, and bare soil. Bare soil was represented by a line of clusters on plots of the ratios TM5/TM4 and TM3/TM4. The soil line was investigated further to determine factors involved in the distributin of clusters alone the line. The clusters representing the bare soil line were also studied by plotting the Tm5/TM4, TM1/TM4 dimension. A total of 76 soil samples were gathered and analyzed for organic carbon

Cheng, Y.

Busacca, A.

Wherry, D.

Hart, J.

Gill, S.

Second Semi -Annual 
Progress Report 
To: National Aeronautics and Space Administration 
Goddard Space Flight Center 
Greenbelt, Maryland 20771 
Contract: NAS5-28758 
T i  t l  e: Spectral characteri  s t i  cs and the extent  o f  pal eosol s 
o f  the Palouse formation 
Principal Investigator:  Dr. B. E. Frazier 
Agronomy and Soi l s  
Washington State University 
Pul lman, WA 991 64 
Coll aborators:  Dr. Alan Busacca 
Yaan Cheng 
Agronomy and Soi l s  
David Wherry 
Judy Hart 
Steve Gil l  
Digi ta l  Image Analysis Laboratory 
( N B S  A-CR- 1797 27 ) S F E C T R B L  CH P.5 A51 E R I S T  IC S 
ANC THE EXTEST OF PALECSCLS Cl THE. PALCUSE 
FCRMATICN S e u i a n n u a l  Erogress H & F O Z t  
[Washinqton S t a t e  U a i v . )  1 2  F CSCL 08G Unclas 
NE7-12034 
63/43 44543 
https://ntrs.nasa.gov/search.jsp?R=19870002601 2020-03-20T13:43:16+00:00Z
Introduction 
The second s i x  month period of our work has been devoted t o  a n a l y s i s  of 
image data and v e r i f i c a t i o n  with additional f i e l d  sampling. 
by objective as  s t a t e d  i n  our proposal. 
We repor t  work 
Progress by Objective: 
I.A. Develop spectral  re la t ionships  from TM data  t h a t  wil l  def ine the 
s p a t i a l  d i s t r ibu t ion  of soi l  areas  by l e v e l s  of (1) organic matter 
in the surface s o i l  , ( 2 )  iron oxide and clay i n  exposed paleosol 
B horizons, and (3) l ime-sil ica accumulations i n  exposed paleosol 
B horizons. 
B. Compare areas determined by t h e  method out l ined i n  A t o  pa t te rns  
interpreted from color aer ia l  photographs, and t o  ground 
observaions on bare-soil f i e l d s .  
Spectral re la t ionships  have been investigated f o r  several bare s o i l  f i e l d s  
which were i n  summer fallow ro ta t ion  on the  date of the imagery. 
Techniques used were t o  examine printouts o f  each band and compare them t o  
aer ia l  photography. Bands with diss imilar  ref lectance pa t te rns  f o r  known 
areas were t h e n  combined u s i n g  r a t i o  techniques which have been proven 
useful i n  other s tud ies  (Wi 11 i ams, 1983). Sel ected r a t i o s  were TMl/TM4, 
TM3/TM4 and TM5/TM4. C1 uster  analyses and Baysi an and Fastcl a s s  c l a s s i f i e r  
images were produced us ing  the three  r a t i o  images. 
analysis  outputs revealed d i s t i n c t  groupings of ref lectance data  representing 
green crops, ripened crops, s o i l  and green plants  and bare s o i l  (Figure 1). 
Bare s o i l  was represented by a l i n e  o f  c l u s t e r s  on p lo ts  of the r a t i o s  
TM5/TM4 and TM3/TM4. 
P lo ts  o f  c l u s t e r  
The s o i l  l i n e  was investigated fur ther  t o  determine f a c t o r s  involved in the 
d is t r ibu t ion  of c l u s t e r s  aiong the l ine.  Each of the  c l u s t e r s  was mapped 
out so t h a t  the landscape posi t ion could be s t u d i e d  and compared t o  aer ia l  
photographs. I t  was noted t h a t  any c lus te r  which was not posit ioned exact ly  
on the 1 ine was not bare s o i l .  C 1  usters  46, 47 and 48 contained varying 
amounts o f  green plant material and c lus te r  16 contained dry plant  material 
i n  addition t o  bare so i l  ( F i g u r e  1). I t  was a l so  noted t h a t  c l u s t e r  17 had 
the lowest TM5/TM4 value and represented s o i l s  w i t h  the lowest carbon 
content. I t  represented paleosols w i t h  l ime-sil ica horizons exposed on the 
surface.  
organic carbon and no l ime-si l ica .  I t  represented paleosols having exposed 
Bw hor i zons . 
Cluster 18 was c lose ly  associated on the landscape, had l i t t l e  
The c l u s t e r s  representing the bare soil  l i n e  were a l so  studied by p lo t t ing  
them t o  observe the TM5/TM4, TMl/TM4 dimension (Figure 2 ) .  From t h i s  view 
the l i n e  was spread o u t ,  forming a plane. The  reasons f o r  t h i s  remain 
unknown; however the p lo t  was used t o  group c l u s t e r s  i n t o  adjacent  blocks 
along the TMS/TM4-TM3/TM4 l i n e .  
studied t o  determine where breaks could logical ly  be made. 
c l u s t e r s  were then mapped using a Baysian c l a s s i f e r  and f i e l d  checked. 
Landscape u n i t s  were found 
paleosols w i t h  Bk horizons and l i g h t  brown paleosols w i t h  Bw horizons 
The landscape posit ion of each c l u s t e r  was 
The  blocks of 
including convex knobs with both white 
exposed, steep south-facing s t r a i g h t  slope pos i t i ons ,  moderate convex 
south-facing slopes, s u m i t s  and nor th - fac ing  concave p o s i t i o n s  and low- 
l y i n g ,  f l a t  pos i t i ons .  
S o i l  samples were c o l l e c t e d  w i t h i n  3 X 3 p i x e l  squares w i t h i n  each mapped 
area. Th is  s i z e  was chosen because it was la rge  enough t o  be l oca ted  e a s i l y  
w i thout  the  use of surveying equipment. Smaller squares were used f o r  u n i t s  
where exact l o c a t i o n  i n  the  f i e l d  was obvious because o f  exposed pa leoso ls  
and mapped areas were smal ler  than 3 X 3 p i x e l s .  
A t o t a l  of 76 samples were gathered and analyzed f o r  o rgan ic  carbon. 
Means were computed f o r  each o f  f i v e  landscape classes which were 
der ived from t h e  b locks o f  c l u s t e r s .  The means o f  DN values o f  t he  r a t i o  
bands f o r  each of t he  landscape classes were regressed aga ins t  the  means f o r  
organic carbon. 
organic carbon (Table 1). 
could be used t o  model organic  carbon content  o f  bare d r y  s o i l ,  b u t  t h e  
best  s i n g l e  r a t i o  i s  TM5/TM4. 
Resul ts  show t h a t  the s o i l  l i n e  i s  a f fec ted  s t r o n g l y  by 
Based on t h i s  ana lys is  any o f  t h e  r a t i o  bands 
The organic carbon data (Table 2 )  were a l so  analyzed by landscape 
categor ies us ing  ANOVA and the  LSD t e s t  t o  determine i f  they were 
s i g n i f i c a n t l y  d i f f e r e n t  from each other. Since t h e  standard dev ia t i ons  of 
the  carbon values increased as the  means increased, we d i d  t h e  s t a t i s t i c a l  
analyse on l o g  transformations o f  the means. These t e s t s  were used t o  
determine whether the  b locks o f  c lus te rs ,  which were de r i ved  e m p i r i c a l l y  
and which looked separable on maps, were s t a t i s t i c a l l y  separable. Carbon 
values expla ined 84% o f  t he  d i f f e rences  observed i n  t h e  f i r s t  ANOVA, b u t  
the  LSD t e s t  showed two p a i r s  o f  classes t h a t  were n o t  separable (Table 3 ) .  
Reexamination o f  t he  o r i g i n a l  da ta  showed t h a t  t h e  two classes w i t h  low carbon 
values were paleosols  which were c l o s e l y  associated on t h e  landscape. 
These can be l o g i c a l l y  combined based on carbon values. 
which was n o t  adequately separated had moderate l e v e l s  o f  carbon. 
t h e i r  means d i f f e r  by l e s s  than 0.4% one could argue t h a t  they too could be 
combined and the  map would s t i l l  be use fu l ;  however, they represent  
d i s t i n c t l y  d i f f e r e n t  areas o f  t he  landscape. 
The other  p a j r  
Since 
We s tud ied  t h e  o r i g i n a l  data again w i th  the  a e r i a l  photographs 
and found t h a t  th ree  sample p o i n t s  i n  the  moderately convex south- fac ing 
slope c lass had been taken from areas which were  n o t  r e c e n t l y  c u l t i v a t e d  
p r i o r  t o  the  image date. These samples had carbon values wel? above the  
mean o f  the nex t  higher c lass.  
photographs i n  uncu l t i va ted  vs recen t l y  c u l t i v a t e d  areas. The soil sur face 
would have been smoother i n  the  uncu l t i va ted  areas and probably was slaked 
(crusted) .  The remote sensing system accura te ly  mapped the  area based on 
re f lec tance;  t he  surface l a y e r  was smoother and may have had l e s s  carbon 
than our sample showed. We have n o t  ye t  attempted t o  sampie a s o i l  c r u s t  t o  
determine i f  i t  has l e s s  carbon than the  s o i l  imned ia te ly  below o r  i f  the  
increased re f l ec tance  t h a t  we see i s  due on ly  t o  l e s s  roughness. I f  we 
remove the th ree  samples gathered f r o m  the  slaked areas f r o m  the  ana lys is ,  
the two classes are s t a t i s t i c a l l y  separated (Table 4 ) .  
t h i s  are t h a t  we have no t  removed surface roughness d i f f e rences  and 
d i f fe rences  due t o  s lak ing  o f  t he  s o i l  surface by us ing  the r a t i o  
techni  ques. 
L igh te r  tones are  shown on t h e  a e r i a l  
The i m p l i c a t i o n s  o f  
We conclude from t h i s  t h a t  we can map organic carbon l e v e l s  very well i f  
the s o i l s  a r e  bare and t h a t  the l ime-si l ica  paleosols  a r e  e a s i l y  separated 
and mapped. 
paleosols may b e  separated and mapped. 
We have not found evidence y e t  t o  show i f  o r  how iron enriched 
11. Using se lec ted  t e s t  s i t e s ,  estimate the extent of eroded 
agri  cul t u ra l  soi  1 s of the  Pal ouse region and es tab l  i sh  base1 i ne 
information f o r  comparison with fu tu re  es t imates .  
Using the  carbon c l a s s  map from t h i s  t e s t  s i t e  and our  knowledge of  the  
s o i l s  derived from f i e l d  sampling we found 1039 ha (2569 ac)  
of bare s o i l  (Table 5 ) .  Paleosols which have been completely exposed by 
erosion occupy 2.7% o f  the area.  Low carbon areas  
slopes with s o i l s  1 m (3.3 f t )  o r  l ess  in  depth occupy 20% of the  area.  
These have about 16 cm (6.3 i n . )  o f  epipedon remaining. The moderate 
carbon c l a s s  covers 44% of the area ,  has s o i l s  with 30 cm (11.8 in . )  
epipedons, and has about 1.3 m (4.3 f t )  of s o i l  over a l ime-s i l ica  
paleosol.  
36 cm (14.2 i n )  t o  46 cm (18.1 in )  epipedons and averages 1.3 m (4.3 f t )  t o  
a paleosol. 
the area.  T h i s  c l a s s  should show much more a rea ,  b u t  most of i t  has been 
covered with a l l u v i a l  s o i l  from upper s lope pos i t ions  and i s  accurately 
mapped in to  several  of the other  carbon c lasses .  
on s t eep  south-facing 
The high carbon area covers 28.8% of the s i t e ,  has s o i l s  with 
Low-lying areas  with t h e  highest  carbon content a r e  4.4% of 
Other s i t e s  w i l l  be looked a t  during the n e x t  two report ing periods. 
Literature Cited 
Williams, R .  S.,Jr. ed. 1983. Geological Applications. In 
Manual o f  Remote Sensing, Second ed. Vol 11. p .  1749, American 
Society o f  Photogrammetry, Falls Church, VA 22046 
Table 1. Regression analysis of organic carbon and average DN value of TM 
band ratios 
Regression Output:TMl/TM4 
Organic Estimated 
Carbon Org. C 
Constant -1 1 .8656 
Std Err of Y Est 0.195542 0.48 
No. of Observations 5 1.45 
Degrees of Freedom 3 1.78 
2.54 
X Coefficient(s) 0.082705 
Std Err of Coef. 0.01 0604 
R Squared 0.952995 1 .oo 
Regression Output:TM3/TM4 
Constant 30.10176 
Std Err of Y Est 0.125760 
R Squared 0.980557 
No. of Observations 5 
Degrees of Freedom 3 
X Coefficent(s) -0.26529 
Std Err of Coef. 0.021 567 
Regression Output:TMS/TM4 
Constant - 4.08519 
Std Err of Y Est 0.041 529 
R Squared 0.997879 
No. of Observations 5 
Degrees o f  Freedom 3 
X Coefficient(s) 0.025865 
Std Err of Coef. 0.000688 
0.48 
1 .oo 
1.45 
1.78 
2.54 
0.48 
1.00 
1.45 
1.78 
2.54 
Regression 0utput:COMBINED 
Constant - 9.83647 
Std Err of Y E s t  0.048989 0.48 
No. of Observations 5 1.45 
Degrees o f  Freedom 1 1.78 
2.54 
X Coefficient(s) -0.02647 0.064705 0.04 
S t a  Err o f  Coef. 0.027115 0.109039 0.01 7888 
R Squared 0.99901 6 1 .oo 
0.54 
0.87 
1.45 
2.03 
2.36 
0.39 
1.18 
1.45 
1.72 
2.51 
0.47 
1.01 
1.42 
1.84 
2.51 
0.48 
1.02 
1.41 
1.80 
2.54 
Table 2. Organic carbon sample da ta  gathered from within map u n i t s  derived 
from groups o f  DN da ta  clusters. 
pixel area.  
Each point  represents a 3 x 3 
Steep Moderate Summits and F1 a t  
Bk Paleosols Bw Paleosols south slopes south s lopes north s lopes  low-lying 
0.51 0.32 0.77 
0.44 0.63 0.88 
0.60 0.66 0.88 
0.24 0.61 0.65 
0.34 0.45 1.19 
0.79 
1.06 
0.95 
1.23 
1.51 
0.85 
0.81 
0.97 
1.34 
1.06 
1.06 
0.79 
1.02 
1.30 
1.34 
1.58 
1.94* 
1.74* 
1.33 
1.62 
1.36 
1.40 
1.74 
1.31 
1.84 
0.67 
1.79* 
0.73 
1.55 
1.37 
1.13 
1.69 
1.69 2.42 
1.37 2.67 
1.29 
2.06 
2.00 
1.65 
1.63 
1.54 
1.76 
1.97 
1.66 
1.85 
1.85 
1.89 
1.89 
1.70 
1.71 
1.62 
1.74 
2.23 
1.82 
1.83 
2.22 
1.69 
1.72 
2.03 
* Samples known t o  have come from slaked areas  
Table 3 .  T t e s t s  (LSD) f o r  carbon value 
Alpha = 0.05 DF = 70 MSE = 0.052 
C r i t i c a l  va lue  o f  T = 1.99 
Least  S i g n i f i c a n t  D i f f e rence  = 0.268 
Means w i t h  the  same l e t t e r  a re  no t  s i g n i f i c a n t l y  d i f f e r e n t  
Carbon Transformed Mean 
Bk Paleosols  
Bw Pal eosol  s 
Steep South Slopes 
Moderate South S1 opes 
Sumnits and Nor th  Slopes 
F1 a t ,  Low-Lyi ng 
0.43 
0.53 
1 .oo 
1.45 
1.78 
2.54 
-0.9022 A 
-0.6620 A 
-0.0174 B 
0.3377 C 
0.5666 C 
0.9329 D 
Table 4. T tests (LSD) f o r  carbon value. Three samples from known slaked 
areas removed. 
Alpha = 0.05 OF = 67 MSE = 0.50 
C r i t i c a l  value of T = 1.996 
Least S ign i f i can t  Difference = 0.266 
Means w i t h  t h e  same l e t t e r  a r e  not s i g n i f i c a n t l y  d i f f e r e n t  
% 
Bk Paleosols 
Bw Pal eosol s 
Steep South Slopes 
Moderate South S1 opes 
Summits and North Slopes 
F1 a t ,  Low-Lyi ng 
0.43 
0.53 
1.00 
1.78 
2.54 
1.38 
Transformed Mean 
-0.9022 A 
-0.6620 A 
-0.0174 B 
0.2853 C 
0.5666 D 
0.9329 E 
Table 5. Area o f  exposed paleosols and organic carbon l e v e l s .  
Area 
Bk Paleosols 
Bw Pal eosol s 
Steep South Slopes 
Moderate South S1 opes 
Summits and North Slopes 
F1 a t ,  Low-Lyi ng 
Carbon Percent Percent Acres Hectares 
0 .43  0 . 7  18 7 
0 .53  2 .0  52 21 
1 .oo 20.0 51 4 208 
1.38 44 .0  1131 458 
1 . 7 8  28.8 740 299 
2.55 4.4 114 46 
TOTAL 2569 1039 
61 
TM5/TM4 
I 
2401 I 
I 
18  J 
i 
i 2 2 q  
2 9 y  
16 C J  I 
I 
I 
I 
12q 
! 
10q 
i 
I 
I 
80 
60 
40 
20 
0 
LHE 
I I I I I I 
60 80 :oo 120 20 40 
lW3/TM4 
Figure 1 .  P lo t  of DN c l u s t e r s  f o r  r a t i o  bands TM5/TM4 and TM3/TM4. 
content ranges from 0.5% a t  c l u s t e r  17  t o  2.5% a t  c l u s t e r  61. 
Carbon 
SOL PLANE 
RIPENED CROPS 
WATER LINE 
GREEN CROPS 
I 
1 
I 
I I I :00 : 20 140 : 60 : 80 20c I i 1 I 0 :  0 20 4 3  60 ao 
TM 1 iTM4 
Figure 2 .  Plot  o f  DN c l u s t e r s  f o r  ra t io  bands TM5/TM4 and TMl/TM4. This 
plo t  shows the s o i l  1 ine as a plane. 
between c l u s t e r s  t o  show blocks representing leve ls  of carbon. 
Some c l u s t e r  numbers a re  changed from Figtire 1 because c l u s t e r s  
lying behind the soil plane have been deleted.  
Lines have been drawn 


Spectral characteristics and the extent of paleosols of the Palouse formation

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