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73-5388
HAKIMIAN, Massoud, 1941EXTRACTAB1LITY OF CARBON, IRON AND ALUMINUM
FRCM SPODIC HORIZONS OF REPRESENTATIVE MICHIGAN
SPODOSOLS, USING VARIOUS CHELATING AGENTS.
Michigan S t a t e U n i v e r s i t y , Ph.D., 1972
A g r i c u l t u r e , s o i l scienc e

University Microfilms, A XEROXC om pany, Ann Arbor, Michigan

EXTRACTABILITY OF CARBON, IRON AND ALUMINUM FROM
SPODIC HORIZONS OF REPRESENTATIVE MICHIGAN
SPODOSOLS, USING VARIOUS CHELATING AGENTS
By
Massoud H akim ian

A THESIS
Subm itted to
M ichigan S t a t e U n i v e r s i t y
in p a r t i a l f u l f i l l m e n t of th e requirem ents
f o r th e degree of
DOCTOR OF PHILOSOPHY
D e p a rtm e n t o f Crop and S o i l S c i e n c e s
1972

PLEASE NOTE:

Some p a g e s may h a v e
indistinct
Fi l me d a s

Uni ve rsi ty Microfilms,

print.
rec e iv e d .

A X e r o x E d u c a t i o n Company

ABSTRACT
EXTRAC TAB I L I TY OF CARBON, IRON AND ALUMINUM FROM
SPODIC HORIZONS OF REPRESENTATIVE MICHIGAN
SPODOSOLS, USING VARIOUS CHELATING AGENTS
By
Massoud H akimian

S o i l sam ples of th e sp o d ic B h o riz o n s

o f some r e p r e ­

s e n t a t i v e M ichigan S p o d o s o ls , as w e ll a s , t h e A h o r i z o n s , t h e
arg illic

horizon,

o r t s t e i n and t h e f r a g i p a n were s u b j e c t e d

t o e x t r a c t i o n w ith d i f f e r e n t i n o r g a n i c and o rg a n ic c h e l a t i n g
agents

o f v a r y i n g pH.

The a m o u n t s o f e x t r a c t a b l e i r o n a n d

a lu m i n u m w e r e d e t e r m i n e d i n t h e s o i l e x t r a c t s .

Th e a m o u n t s

o f e x t r a c t a b l e c a r b o n w ere d e te r m in e d from t h e d i f f e r e n c e
betw een th e t o t a l c arb o n of t h e s o i l sam ples b e f o r e and
a fte r extraction.
S t a t i s t i c a l analysis

of th e e x tra c tio n d ata re v e als

t h a t t h e O.IM Na2 ~NTA, O.IM Na^PgOy a n d O.IM Na2 ~EDTA e x ­
t r a c t i o n p r o c e d u r e s f o r Fe p r o d u c e d e c r e a s i n g a m o u n t s w i t h
s i g n i f i c a n t d i f f e r e n c e s b e tw e e n them .
re s u lte d in th e p r e c ip ita tio n

Na^-DPTA, a t pH 1 2 ,

o f Fe i n t h e s o i l e x t r a c t .

Th e O.IM Na^-DPTA a n d O.IM Nag-NTA e x t r a c t a b l e A1 w e r e
com parable.

H ow eve r DPTA e x t r a c t a b l e A1 r e s u l t s w e r e s i g n i ­

f i c a n t l y h i g h e r t h a n f o r O.IM Na2 ~EDTA a n d O.IM N a ^ - P 2 0 ^ .
The O.IM Na2 -NTA i s

s u g g e s t e d t o b e a s u i t a b l e A1 e x t r a c t o r .

M assoud H akim ian
The low pH s o l u t i o n s
tractan ts

fo r carbon.

(EDTA a n d NTA) w e r e g o o d e x ­

H o w e v e r , EDTA r e s u l t s w e r e s i g n i f i ­

c a n tly g r e a t e r than f o r th e o th e r e x t r a c t a n t s .

NTA p r o d u c e d

c o m p a r a b l e r e s u l t s w i t h t h e h i g h pH e x t r a c t a n t s .
I n g e n e r a l t h e O.IM Na2 ~NTA o f f e r s g r e a t e r p r o m i s e a s
a n e x t r a c t a n t o f F e , A1 a n d C, a n d h e n c e a s a c l a s s i f i c a t i o n
to o l,

t h a n e x t r a c t a n t s w h ic h w ere e q u a l l y o r more " e f f i c i e n t "

i n e x t r a c t i n g A l (DPTA) o r C (EDTA).
The a m o u n t o f e x t r a c t a b l e i r o n a n d a l u m i n u m i s
low est in th e p o o rly d ra in e d K in ro ss pedon.

the

However, t h e

maximum Fe a c c u m u l a t i o n o c c u r s i n t h e s o m e w h a t - p o o r l y t o mo­
d e r a t e l y w e l l - d r a i n e d A u G r e s - C r o s w e l l member o f a s a n d y t o p o sequence.

E x t r a c t a b l e a l u m i n u m maximum o c c u r s i n t h e s o m e ­

w h at-p o o rly d ra in e d Saugatuck-A uG res.

The m a g n i t u d e o f t h e

Al complex e x t r a c t e d by t h e c h e l a t i n g a g e n t s u s u a l l y ex ceed ed
t h e c o r r e s p o n d i n g amounts o f i r o n .

The l o w e s t e x t r a c t a b l e C

o c c u r r e d i n t h e w e l l - d r a i n e d member o f t h e d r a i n a g e c a t e n a ,
nam ely C r o s w e ll- G r a y c a lm , w h i l e t h e h i g h e s t amount o f t h e
e x t r a c t a b l e c a r b o n was f o u n d i n t h e so m e w h a t p o o r l y - d r a i n e d
Saugatuck-A uG res.
The a m o u n t o f i l l u v i a l F e , A l a n d C i n c r e a s e s w i t h
th e i n c r e a s e i n th e p ed o g en ic developm ent o f th e s p o d ic h o r i ­
zons of t h e w e l l - d r a i n e d S p o d o so ls s t u d i e d .
s p o d i c Bs (Omega a n d E a s t p o r t )

Thus t h e w e a k e s t

c o n t a i n e d t h e l o w e s t amount

o f e x t r a c t a b l e F e , A l a n d C, w h i l e t h e s t r o n g e r H i a w a t h a

M assoud H akim ian
a n d M u n i s i n g e x h i b i t t h e h i g h e s t am o u n t o f e x t r a c t a b l e F e ,
A l a n d C.
The a c c u m u l a t i o n p r o d u c t s o f t h e s p o d i c B h o r i z o n a r e
used as a chem ical c r i t e r i a f o r c l a s s i f i c a t i o n of th e Spo­
d osols.

I t is

suggested th a t th e c u rre n tly used r a t i o

of

% e x t r a c t a b l e Fe and A l o v e r % c l a y s h o u ld b e re d u c e d from

.15 t o

.10 t o in c l u d e m ost S p o d o so ls

w e l l - G r a y c a l m and M u n i s i n g ) .

It

is

(A uG res-C rosw ell, C rosa ls o suggested t h a t the

r e q u ire d r a t i o be low ered t o 0.04 fo r th e w e ll- d r a in e d ,
te x tu r e d as w e ll as th e p o o rly - d ra in e d Spodosols
and K i n r o s s ) .

fin e-

(Onaway

Furtherm ore, th e d a ta o b tain ed in t h i s

study

i n d i c a t e t h a t t h e % t o t a l c a r b o n , % e x t r a c t a b l e F e a n d fo
e x t r a c t a b l e Al o v er % c l a y , t h e p r e v io u s c r i t e r i o n
classificatio n

fo r the

of S podosols, p ro v id es a b e t t e r e stim a te

of

the i l l u v i a l m a te r ia l of th e spodic B h o riz o n f o r c l a s s i f i ­
c a tio n purposes in th e s e Spodosols.

TO THE MEMORY OF MY FATHER

ACKNOWLEDGMENTS

S incere g ra titu d e is

e x p r e s s e d t o D r . E. P . W h i t e s i d e ,

th e a u t h o r 's m ajor p r o f e s s o r ,

f o r h is guidance and d e v o tio n

th ro u g h o u t th e course of t h i s

study.

The a u t h o r w i s h e s t o

e x p r e s s h i s a p p r e c i a t i o n t o D r . A. R. W o l c o t t , D r . M. M.
M o r t l a n d , D r . B. G. E l l i s

a n d D r . H. B. S t o n e h o u s e f o r s e r v ­

i n g on h i s PhD. C o m m i t t e e a n d f o r t h e i r h e l p f u l r e m a r k s a n d
suggestions.

S p e c i a l t h a n k s a r e e x t e n d e d t o Mr. J o h n B a r n a r d

f o r h i s h e l p a n d co mm en ts on t h e s t a t i s t i c a l a n a l y s i s
d ata.

of th e

The s o i l t e s t i n g l a b o r a t o r y , t h e s o i l c h e m i s t r y l a b o ­

r a t o r y and t h e g e o c h e m is try l a b o r a t o r y s t a f f w ere a l s o v e ry
h e lp f u l w ith the a n aly se s.
The a u t h o r a p p r e c i a t e s t h e c o o p e r a t i o n a n d u n d e r ­
s t a n d i n g of h i s w if e J e a n and th a n k s h e r f o r t h e t y p i n g o f
th e f i r s t d r a f t of th is m anuscript.
The f i n a n c i a l s u p p o r t o f t h e I r a n i a n g o v e r n m e n t a n d
t h e M ichigan A g r i c u l t u r a l E x p e rim en ta l S t a t i o n a r e a l s o
ap p reciated .

TABLE OF CONTENTS
Page
DED ICATION.....................................................................................................

ii

ACKNOWLEDGMENTS...........................................................................................

iii

LIST OF T A B L E S ...........................................................................................

vi

LIST OF FIGURES...........................................................................................

v iii

INTRODUCTION ................................................................................................
LITERATURE REVIEW.............................................................................
I l l u v i a l S p o d i c H o r i z o n ...................................................
T h e o r ie s of O rganic M a tt e r and S e s q u i o x id e s T r a n s l o c a t i o n and A c c u m u la tio n
i n S u b s o i l ........................................................................
Co m pl e x F o r m a t i o n a n d C h e l a t i o n R e a c t i o n s
. .
S o i l O rganic M a tte r and C h e l a t i o n
.......................
E x t r a c t i o n of O rganic M a t t e r fromS o i l s . . .
MATERIALS AND M E T H O D S ..............................................................

1
3
3
5
8
10
17
30

S o i l s U se d i n t h e S t u d y ..........................................
30
M e t h o d s U s e d i n t h e S t u d y .....................................
39
E x t r a c t i n g p r o c e d u r e ..............................................
40
S o i l e x t r a c t c o l o r ...................................................
40
S o i l e x t r a c t r e a c t i o n ..........................................
40
Fe a n d A l i n t h e s o i l e x t r a c t ...................
40
T o tal carbon in s o i l s b e fo re e x tr a c ­
tio n
42
T o tal carbon in s o i l s a f t e r e x tr a c ­
t i o n ......................................................................................
43
RESULTS AND D I S C U S S I O N ..............................................................
P relim inary
E ffect
E ffect
treatm
Effect

44

S t u d i e s .............................................................
44
of c o n c e n t r a t i o n ofe x t r a c t a n t .
.
44
o f e x t r a c t i o n tim e and s h a k i n g
e n t s ..............................................................
44
o f pH o f t h e e x t r a c t a n t s . . . .
48
iv

P age
P r i n c i p a l S t u d i e s ................................................... . . .
pH o f e x t r a c t i n g s o l u t i o n s b e f o r e
and a f t e r c o n t a c t w i t h t h e s o i l s a m p le s .
C o l o r o f t h e s o i l e x t r a c t s ..............................
Fe e x t r a c t i o n r e s u l t s
.........................................
Aluminum e x t r a c t i o n r e s u l t s
..........................
Carbon e x t r a c t i o n r e s u l t s
...............................
S t a t i s t i c a l a n a l y s e s ..............................................
C l a s s i f i c a t i o n o f t h e s o i l s ..........................

50
51
53
64
70
75
80

SUMMARY AND C O N C L U S I O N S ...................................................................

87

REFERENCES.....................................................................................................

94

v

50

LIST OP TABLES
P age
TABLE
1
2

3

4
5

6
7
8
9

10

11

Some p h y s i c a l a n d c h e m i c a l p r o p e r t i e s o f
t h e p r o f i l e s s t u d i e d .............................................................

32

S o i l t y p e na mes a n d l e g a l d e s c r i p t i o n s o f
l o c a t io n s of th e p r o f i l e s s tu d ie d (s e e a l s o
F i g . 1 ) ...........................................................................................

33

C h e m i c a l f o r m u l a e a n d some o f t h e e q u i l i ­
brium c o n s ta n ts of th e c h e l a t i n g a g e n ts used
i n t h i s s t u d y ............................................................................

4l

E f f e c t s o f c o n c e n t r a t i o n o f e x t r a c t a n t s on
t h e e x t r a c t i o n o f Fe a n d A l f r o m s o i l s . . . .

45

E f f e c t o f s h a k i n g a n d e x t r a c t i o n t i m e on
t h e a m o u n t o f Fe a n d Al e x t r a c t e d b y t h r e e
O.IM c h e l a t i n g a g e n t s
........................................................

47

The e f f e c t o f t h e pH o f O.IM NacDPTA s o l u ­
t i o n s on t h e e x t r a c t a b i l i t y o f F e ...........................

49

pH v a l u e s o f t h e e x t r a c t i n g s o l u t i o n s b e f o r e
a n d a f t e r c o n t a c t w i t h s o i l s a m p l e s ......................

52

C olo r of th e spodic B e x t r a c t s by d i f f e r e n t
e x t r a c t a n t s .................................................................................

5^-

P e r c e n t t o t a l c a r b o n and e x t r a c t a b l e i r o n
and aluminum c o n t e n t of s o i l sam p les w i t h
d iffe re n t ex tractin g solutions (ch elatin g
a g e n t s ) ...........................................................................................
P e r c e n t f r e e i r o n oxide and t o t a l e x ch an g e­
a b l e A l o f some o f t h e s o i l p e d o n s u s e d i n
t h e s tu d y by o r th o p h e n a n th r o lin e c o l o r i ­
m e t r y a n d f l u o r i d e t i t r a t i o n m e t h o d s .......................

67

P ercent of t o t a l carbon a f t e r e x tr a c ti o n ,
p e r c e n t e x t r a c t a b l e c a r b o n , and t h e p e r c e n t
of t o t a l carb o n e x t r a c t e d by th e d i f f e r e n t
e x t r a c t a n t s u s e d i n t h i s s t u d y ....................................

72

vi

56

TABLE
12
13

lb

P age
A nalysis of v a ria n ce of th e e x tr a c ta b le
F e , A l a n d c a r b o n .............................................................

77

The a c c u m u l a t i o n i n d e x a n d t h e p e r c e n t
e x t r a c t a b l e Fe p l u s Al o v e r % c l a y by
d i f f e r e n t e x t r a c t a n t s of s p o d ic h o r iz o n s
u s e d i n t h i s s t u d y ........................................................

83

The r a t i o o f % t o t a l C, % e x t r a c t a b l e F e ,
and % e x t r a c t a b l e Al o v e r $ c l a y f o r
s p o d i c h o r i z o n s u s e d i n t h e s t u d y .....................

86

LIST OF FIGURES

FIGURE
1
2

3

Page
Map o f M i c h i g a n s h o w i n g l o c a t i o n s o f
r e p r e s e n ta tiv e s o ils used in the study

. . .

3^

E x tra c ta b le iro n co n ten t of s e le c te d
h o riz o n s of pedons s tu d ie d u sin g d i f f e r ­
e n t e x t r a c t a n t s ........................................................

58

E x t r a c t a b l e aluminum c o n t e n t o f s e l e c t e d
h o riz o n s of pedons s tu d ie d u s in g d i f f e r ­
e n t e x t r a c t a n t s ........................................................

59

v iii

INTRODUCTION

Spodosols
by a d i a g n o s t i c

( p o d z o ls ) a r e s o i l s w hich a r e c h a r a c t e r i z e d
s u b su rfa c e h o riz o n , th e spodic h o riz o n .

spodic h o riz o n i s
illu v ia l

The

on e i n w h i c h a r e l a t i v e l y h i g h c o n t e n t o f

o r g a n ic m a t t e r and s e s q u i o x i d e s

occurs.

These su b ­

s t a n c e s form an a c t i v e amorphous m a t e r i a l w i t h a h i g h e x ­
change c a p a c ity ,

large surface area,

and h ig h w a te r r e t e n ­

tio n property.
I n b o r d e r - l i n e c a s e s where t h e m o rp h o lo g ic a l f e a t u r e s
a r e so w eakly e x p re ss e d as t o p r e v e n t th e i d e n t i f i c a t i o n
such s o i l s i n t h e f i e l d by t h e s o i l s c i e n t i s t ,

of

th e chem ical

c r i t e r i a b a s e d on t h e l a b o r a t o r y m e a s u r e m e n t s o f o r g a n i c
m a t e r i a l a n d s e s q u i o x i d e s w o u l d b e o f much v a l u e i n i d e n t i ­
f i c a t i o n and c l a s s i f i c a t i o n

of th ese s o ils .

One o f t h e t h e o r i e s c o n c e r n i n g t h e f o r m a t i o n o f
spodic h o rizo n s p o s tu la te s

th e m utual f l o c c u l a t i o n

tiv e ly charged sesquioxide c o llo id s
organic c o l l o i d s .

O ther t h e o r i e s

of p o s i­

and n e g a t i v e l y c h a rg e d

suggest the changes in

r e d o x - p o t e n t i a l o r i n pH a s a p r i m a r y c a u s e f o r o r g a n i c
m a t e r i a l and s e s q u io x id e s f l o c c u l a t i o n .

The m o r e r e c e n t a n d

a c c e p te d t h e o r i e s i n d i c a t e th e in v o lv em en t of a c h e l a t i o n
1

2
r e a c t i o n and e l e c t r o s t a t i c bonds i n t h e a s s o c i a t i o n betw een
organic m a tte r,

i r o n , and aluminum.

S u c h co mp ou nds a r e

s o l u b l e a n d a r e i m m o b i l i z e d w he n : t h e c o n c e n t r a t i o n o f s e s ­
quioxide reaches a c r i t i c a l
o r g a n i c m e ta l complex i s

lev el,

or th e h y d ro ly sis o f th e

i n d u c e d b y a c h a n g e i n pH, o r t h e r e

i s b io l o g i c a l d e s tr u c ti o n of organic lig a n d s .
A l a r g e n u m b e r o f o r g a n i c com po unds w i t h a p p r o p r i a t e
e le c tr o n - d o n o r groups c a p a b le o f c h e l a t i n g th e m e ta ls can be
used to e x tr a c t th e organic m a tte r,

i r o n and aluminum from

t h e im m o b iliz e d amorphous m a t e r i a l o f t h e s p o d ic h o r i z o n .
The o b j e c t i v e s

of th is

study a re as fo llo w s:

( 1 ) To s t u d y v a r i a t i o n s
v i a l organic carbon,

of the e x tra c ta b le i l l u ­

i r o n and aluminum c o n t e n t s

of th e spodic

h o r iz o n w ith d i f f e r e n t i n o r g a n i c and o rg a n ic aqueous c h e ­
l a t i n g a g e n ts and t h e i r r e l a t i o n s h i p

t o t h e pH o f t h e

ex tractio n .
( 2 ) To i n v e s t i g a t e t h e e x t r a c t a b i l i t y

of i l l u ­

v i a l o r g a n i c c a r b o n , i r o n and aluminum o f t h e s p o d i c h o r i z o n
as a f f e c t e d by th e p o s i t i o n o f t h e ground w a te r ( i n a to p o seq u en ce o f S p o d o s o ls ) and th e d e g re e o f s p o d ic h o r i z o n
developm ent ( i n w e l l - d r a i n e d S podosols w ith v a r y in g d e g re es
of spodic h o riz o n developm ent).
( 3 ) To e v a l u a t e t h e r e l a t i v e

su itab ility

of the

v a r i o u s e x t r a c t i n g a g e n ts i n t h e c h a r a c t e r i z a t i o n and c l a s s i ­
ficatio n

o f t h e p e d o n s s t u d i e d a c c o r d i n g t o t h e ne w S o i l

T ax onom y, 1 9 7 0 .

LITERATURE REVIEW

I l l u v i a l Spodic H orizon
The e a r l y W e s t e r n E u r o p e a n o b s e r v e r s
its

o f o r t s t e i n and

s u b s e q u e n t r e c o g n i t i o n by R u s s ia n w o rk e rs b r o u g h t a b o u t

t h e i d e a o f t h e downward t r a n s l o c a t i o n o f s u b s t a n c e s
the upper lay ers

o f th e s o i l t o low er l a y e r s .

from

In g en eral,

t h e t r a n s f e r e n c e was t h o u g h t o f a s o c c u r r i n g i n s o l u t i o n .
P a v l i n o v i n 1887 s u g g e s t e d t h a t t h e mo ve m e nt o f c l a y p a r t i ­
cles

o ccurs i n s o l u t i o n (M uir,

1961).

However, t h e more

g e n e r a l c o n c e p t o f i l l u v i a t i o n i n t h e p e d o l o g i c a l s e n s e was
s u g g e s t e d b y V y s o t z k y i n 1 8 8 9 , who d e f i n e d t h e i l l u v i u m a s
t h e m a t e r i a l washed o u t o f t h e s u r f a c e s o i l and d e p o s i t e d
below t o form a d e f i n i t e h o r i z o n o f a c c u m u l a t i o n ,
th e i l l u v i a l h o riz o n (M uir,

1961).

such as

Z a k h a r o v i n 1906 a d v o ­

c a te d th e r e c o g n itio n of th e i l l u v i a l h o riz o n as a p a r t of
t h e p o d z o l i c p r o f i l e and p ro p o s e d t h a t t h e f o ll o w i n g l e t t e r s
should sym bolize th e v a rio u s h o riz o n s :
zon; B, t r a n s i t i o n a l
v ial

(o rtstein )

A, u p p e r humus h o r i ­

or p o d z o l i c - e l u v i a l h o riz o n ;

h o r i z o n ; D, p a r e n t m a t e r i a l .

C, i l l u ­

This p a r t i c u ­

l a r u s a g e o f s y m b o l s c o n t i n u e d among many R u s s i a n w o r k e r s
u n t i l a b o u t 1 9 3 0 , w he n t h e f o r m e a r l i e r p r o p o s e d b y G l i n k a :
A, e l u v i a l ; B , i l l u v i a l ;

C, p a r e n t m a t e r i a l , w i t h t h e a d d i t i o n
3

4
o f num eral s u b s c r ip ts
(M uir,

f o r s u b d i v i s i o n s , became t h e s t a n d a r d

1 961 ).
S t o b b e and W r ig h t (1 9 5 9 ) g i v e a more d e f i n i t e d i s ­

t i n c t i o n b etw een t h e i l l u v i a l h o r iz o n and o t h e r h o r iz o n s

of

a c h a r a c t e r i s t i c p o d z o l s o i l i n t h e f o l l o w i n g s eq u e n c e where
A0 o r C>2 h o r i z o n i d e n t i f i e s

th e organic s u rfa c e la y e r .

D ir e c tly under th e s u rfa c e organic h o rizo n i s

a lig h t-co lo red

e l u v i a l A2 h o r i z o n w h i c h h a s l o s t r e l a t i v e l y m o r e s e s q u i o x i d e
th an s i l i c a .

The A2 h o r i z o n r e s t s

over a d ark -co lo red i l l u ­

v i a l h o r i z o n i n w hich t h e o r g a n i c m a t e r i a l and s e s q u i o x i d e s
l e a c h e d f r o m t h e A2 h o r i z o n h a v e a c c u m u l a t e d .
Th e new c o m p r e h e n s i v e s y s t e m o f s o i l c l a s s i f i c a t i o n
d e v e lo p e d by t h e U .S. D e p a rtm e n t o f A g r i c u l t u r e

( S o i l Taxo­

nomy , 1 9 7 0 , u n e d i t e d ) d e f i n e s s p o d i c h o r i z o n s a s d i a g n o s t i c
s u b - s u r f a c e i l l u v i a l h o riz o n s w hich a r e c h a r a c t e r i s t i c
tu res

of most S p o d o so ls

fea­

( p o d z o l s ) and a r e d e v e lo p e d from

medium t o c o a r s e - t e x t u r e d m a t e r i a l u n d e r h u m id e n v i r o n m e n t
and f o r e s t

or h e a th v e g e t a t io n .

a c t i v e amorphous m a t e r i a l s

These h o riz o n s c o n ta in

composed o f o r g a n i c m a t t e r and

aluminum, w ith or w i t h o u t i r o n .

Th e w o r d " a c t i v e "

to d e s c r ib e m a t e r i a l havin g high exchange c a p a c ity ,
surface area,

and h ig h w a te r r e t e n t i o n .

is

used

large

5
T h e o r ie s of O rganic M a t t e r and S e s q u io x id e s
T r a n s l o c a t i o n and A c cu m u la tio n ~ in S u b s o i l
The m echanism s by w h ich t h e o r g a n i c m a t t e r a nd s e s q u i ­
oxides, p a r t i c u l a r l y th e l a t t e r ,

have b e e n removed from t h e

A h o r iz o n s and d e p o s i t e d i n th e i l l u v i a l B h o r i z o n ,
been of most co n cern i n th e p ro c e s s
ever,

have

of p o d z o liz a tio n .

How­

t h e p o d z o l i z a t i o n p r o c e s s w i l l n o t b e t a k e n t o me an

only th o s e r e a c t i o n s

i n v o l v e d i n m o b i l i z a t i o n and s u b s e q u e n t

d e p o sitio n of sesquioxides in the pedo-sphere.
w i l l b e n e c e s s a r y t o c o n s i d e r t h e sum t o t a l

R ather,

it

of a l l th e r e ­

a c t i o n s a p p a r e n t l y a s s o c i a t e d w ith t h e developm ent of t h e
k i n d and s e q u e n c e o f s o i l h o r i z o n s d e s c r i b e d by S t o b b e and
W right as c h a r a c t e r i s t i c
In g eneral,

of podzols.

th e r e a re th r e e groups of r e a c tio n s

as b e in g c o n t r i b u t o r s t o p o d z o l i z a t i o n .
1934,

1942) t h e o r i e s

M a ttso n 's

cited

(1 9 3 1 *

on i s o e l e c t r i c w e a t h e r i n g , w h i l e a p ­

p e a r i n g q u i t e sound c h e m i c a lly ,

r e q u i r e a pH g r a d i e n t w i t h

d e p t h i n t h e s o i l w h i c h i s n o t commonly f o u n d i n p o d z o l s .
B e f o r e t h i s mechanism i s

l i g h t l y dism issed,

however,

consi­

d e r a t i o n s h o u ld b e g iv e n t o t h e mechanism as b e i n g r e a s o n a b l y
im portant in the e a r l i e s t

s t a g e s o f p o d z o l d e v e l o p m e n t when

t h e r e may b e a s u f f i c i e n t pH g r a d i e n t i n t h e p r o f i l e .
A more w i d e l y a c c e p t e d r e a c t i o n u s e d t o e x p l a i n p o d ­
z o liz a tio n has been th e c i t a t i o n
ence i n s o l u b i l i t i e s
quioxides

of iro n .

of th e s ig n if ic a n t d i f f e r ­

of th e reduced versu s th e o x id ized s e s ­
Link ( 1958) r e p o r t s v a rio u s s o l u b i l i t y

6
p r o d u c t ( KSp ) v a l u e s f o r f e r r o u s

o x i d e (FeO) a n d f e r r o u s

h y d r o x i d e Fe (O H )g r a n g i n g f r o m 7x l O - 1 3 t o 4 . 5 x l 0 ~ 2 1 .

The

1

Ko

f i g u r e s most a c c e p te d by L ink ( i b i d . )

2 5 °C o r a s o l u b i l i t y

a r e 8x10"

o f a b o u t 1 . 5x l O "5 m o l e s / l i t e r a t 2 5 ° C .

S o lu b ility products fo r f e r r i c

o x i d e ( F e 2 C>2 ) a n d f e r r i c

h y d ro x id e F e ^ H ) ^ a r e r e p o r t e d by Link ( i b i d . )
3 . l 6xlO - ^

at

o r 3 . 2 x l O ” 36 an(j s o l u b i l i t i e s

as b e in g

as b e i n g from 3 t o

3.4 x 1 0 -1 ® m o l e s / l i t e r .
To s u b s t a n t i a t e t h i s m e c h a n i s m o f r e d u c t i o n t o t h e
fe rro u s s t a t e in th e A horizon w ith a subsequent o x id a tio n to
cause p r e c i p i t a t i o n i n th e B horizon*

i t m u s t b e s ho wn t h a t

s u c h r e a c t i o n s a r e i n d e e d a c t i v e i n s o i l s t h a t show a d v a n c e d
p o d zo l m orphology.

M c K e n z i e a n d E r i c k s o n ( 1 9 5 ^ ) made r e d o x -

p o t e n t i a l m e a s u r e m e n t s i n tw o p o d z o l p r o f i l e s

d u r i n g on e

summer a n d f o u n d s l i g h t b u t d e f i n i t e e v i d e n c e o f h i g h e r o x i ­
d ation p o te n tia ls

in th e B h o rizo n th an in th e A h o riz o n .

l a t e r p a p e r b y M cK en zi e*
tials

ert a l .

A

( i 960) re p o rte d redox p o te n ­

f o r a tw o y e a r p e r i o d a n d f u r t h e r c o n f i r m e d t h a t Bi r

horizons

of podzols have a h ig h e r o x id iz in g p o t e n t i a l th a n

do e i t h e r o v e r l y i n g o r u n d e r l y i n g l a y e r s .

The c a u s e o f t h e

o b s e r v e d v a r i a t i o n i n r e d o x p o t e n t i a l s b e t w e e n t h e A* B a n d
C h o r i z o n s was f u r t h e r e x a m i n e d b y M c K e n z i e , et_ al_.
They fo u n d t h a t f e r r i c

citrate

(ib id .).

o x i d i z i n g o r g a n i s m s w e r e many

t i m e s m o r e common i n t h e A h o r i z o n t h a n i n Bi r h o r i z o n .
i m p lic a tio n s a re t h a t d ic a r b o x y lic and t r i c a r b o x y l i c

Th e

acids

a r e f o r m e d i n t h e s o i l a n d a c t a s c o m p l e x i n g o r g a n i c co mpo unds
w ith th e m e ta ls.
Th e i n f e r e n c e b y M c K e n z i e , a t a l .
organo complex i s

t h a t a m etal-

i n v o l v e d a s a v e h i c l e i n t h e m o ve m e nt o f

iro n in the p r o f ile

s e r v e s t o i n t r o d u c e a n o t h e r mechanism

commonly d e s c r i b e d b y s o i l s c i e n t i s t s
p o d zo lizatio n .

(ib id .)

K aurichev,

et. a T .

as b e in g i n v o l v e d i n

( 1 9 5 8 ) s u m m a r i z e s much o f

t h e R u s s i a n r e s e a r c h on t h e f o r m a t i o n o f i r o n - o r g a n o c o m p l e x e s
in the pro cess

o f p o d z o l i z a t i o n as fo llo w s :

"l.

In s o i l s w ith tem porary excess m o is tu re ,
reducing processes appear during th e sp rin g
th a t le ad to th e form ation of fe rro u s ir o n .

"2.

The f e r r o u s i r o n , r e a c t i n g w i t h w a t e r - s o l u b l e
o r g a n ic s u b s t a n c e s , forms complex o r g a n ic
i r o n compounds.
Upon l a t e r o x i d a t i o n o f t h e
i r o n t h e s e com po un ds m a i n t a i n a h i g h s o l u b i ­
l i t y and m ig r a te th ro u g h t h e s o i l .

"3.

There i s a p o s s i b i l i t y of th e fo rm a tio n of
c o m p l e x o r g a n i c - i r o n com pound s u n d e r c o n d i ­
t i o n s o f t h e f o r m a tio n of p o d z o l i c and bog
s o i l s as w e l l as s o l o t h s , s o l o n e t z and
d e p ressio n podzolized s o i l . "

B l o o m f i e l d (1 9 5 3 * 1 9 5 ^ ) f o u n d t h a t a q u e o u s l e a c h a t e s
f e ro u s and b r o a d le a f e d f o r e s t l i t t e r
drated f e r r ic
tio n

of c o n i­

re a d ily d isso lv e d hy­

and aluminum o x id e w i t h t h e s u b s e q u e n t f o r m a ­

o f s o l u b l e f e r r o u s and aluminum com plex compounds.

a mechanism w ould remove t h e n e c e s s i t y o f f i r s t

Such

reducing the

i r o n as i s n e c e s s a r y i n t h e scheme p o s t u l a t e d by K a u r i c h e v ,
et a l . (ib id .).

However, a n o t h e r mechanism o r o t h e r m echa­

nism s a r e n e c e s s i t a t e d f o r s to p p in g th e m o b iliz e d m a t e r i a l s
in th e B horizon.

8
From t h e d a t a p r e s e n t l y a v a i l a b l e i t
s i n g l e mechanism i s

to tally

tra n s p o rt in the process

a p p e a r s t h a t no

re sp o n sib le fo r sesquioxide

of p o d z o liz a tio n .

The r e d u c t i o n i n

t h e A h o r i z o n s , mo ve m e nt a n d s u b s e q u e n t o x i d a t i o n i n t h e B
horizon ap p ears,

from l a b o r a t o r y and f i e l d d a t a ,

p l a u s i b l e m echanism .

to be a very

Co m pl e x m e t a l a n d o r g a n i c c o m p o u n d s

h a v e b e e n shown t o b e a p l a u s i b l e s o l u b i l i z i n g m e c h a n i s m ,
b o th w i t h com plexes

of th e f e r r i c

and f e r r o u s io n s as w e l l as

w i t h a l u m i n u m f o r t h e i r move me nt i n t h e s o i l .
e v i d e n c e now se e m s t o b e i n

F u rther f ie ld

o r d e r t o e s t a b l i s h t h i s mechanism

as a m ajor c o n t r i b u t o r i n th e p o d z o l i z a t i o n p ro c e s s .
C o m pl e x F o r m a t i o n a n d C h e l a t i o n R e a c t i o n s
M a r t e l l and C a l v i n (1952) have d e s c r i b e d a com plex as
b e i n g a s u b s t a n c e w i t h an e l e c t r o n donor t h a t com bines w ith
th e m etal io n .

However, i f t h e s u b s t a n c e w hich com bines

w i t h t h e m e t a l p o s s e s s e s two o r more d o n o r g r o u p s so t h a t
on e o r m o r e r i n g s a r e f o r m e d , a c h e l a t e compound o r m e t a l
ch elate is

formed and t h e donor i s

s a id to be a c h e la tin g

agent.
The a u t h o r s

r e p r e s e n t s c h e m a t i c a l l y sim p le examples

o f complex f o r m a t i o n and c h e l a t i o n r e a c t i o n s i n t h e f o l l o w i n g
manner, w ith o u t f u r t h e r c o n s i d e r a t i o n of th e n a t u r e
bonds:
I - M e t a l Co m pl e x

A
M + 4 A = A -lyl- A
A

of the

9
II

- M etal C h e la te

Where:

A-A
M
A

A
M + 2 A-A = A -fy - A
A

rep resen ts a c h ela tin g agent
re p re s e n ts a m etal ion
r e p r e s e n t s a com plexing a g e n t

T h i s t y p e o f r i n g f o r m a t i o n was t e r m e d c h e l a t i o n b y M o rg a n
a n d Drew ( M a r t e l l a n d C a l v i n ,
used to cover a l l types

1952) and t h e te rm h as b een

of r i n g system s w ith m e ta l and w ith

h y drogen, w ith o u t r e g a r d t o t h e n a t u r e of th e c h em ica l bond
involved.

However, as i n o r d i n a r y com plex compounds, t h e

ty p e o f l i n k a g e which b in d s th e m e ta l i n t o t h e c h e l a t e

ring

may b e t h e o r d i n a r y c o v a l e n t o r t h e c o o r d i n a t e c o v a l e n t t y p e
w i t h some p a r t i a l i o n i c c h a r a c t e r o f t h e s e c o v a l e n t b o n d s .
S i n c e many o r g a n i c m o l e c u l e s h a v e m o r e t h a n t w o p o s i t i o n s
th r o u g h which c o v a l e n t or c o o r d i n a t e c o v a l e n t bonds w i t h t h e
m e t a l may b e f o r m e d , t h e t e r m s u n i d e n t a t e , b i d e n t a t e ,
den tate,

q uadridentate,

e tc.,

w e re p r o p o s e d by Morgan t o

d e n o te com plexes form ed w i t h m o le c u le s
one, two, t h r e e ,
O bviously,

four,

e tc.,

tri-

or io n s c o n ta in in g

donor groups r e s p e c t i v e l y .

com plexes w i t h u n i d e n t a t e s u b s t a n c e s would n o t

in v o lv e c h e la tio n .

T a b l e 3 i n t h e M e t h o d s s e c t i o n shows t h e

c h e m ic a l fo rm u la e and c h a r a c t e r i s t i c s

o f some c h e l a t i n g

agents used.
The f a c t o r s

c o n trib u tin g to the s t a b i l i t y

c h e l a t e a r e d i s c u s s e d b y Lehman ( 1 9 6 3 ) .
fies

such f a c t o r s

ion,

(2) e f f e c t

in th re e c a te g o rie s:

o f 1c h e l a t i n g a g e n t ,

of a m etal

The a u t h o r c l a s s i ­
(l)

effect

(3) effect

of

of m etal

10
environm ent.

B a s e d on t h e t y p e o f b o n d s f o r m e d ,

c h a r g e , and th e e l e c t r o - n e g a t i v i t y
a r o l e i n t h e complex s t a b i l i t y .
its

in f lu e n c e through:

of th e m etal ion p lay s
A c h e la tin g agent exerts

t h e number o f r i n g s form ed by a

m o le c u le o f c h e l a n t and t h e m e ta l i o n ;
late

ring;

the size

steric

Among t h e e n v i r o n m e n t a l f a c t o r s

la tio n equilibrium ,

e f f e c t s and e n tro p y
a ffe c tin g the che­

tem perature plays a r o le .

tem perature g e n e ra lly r e s u l t s
constant.

of the che­

t h e donor atom , which d e te r m in e s t h e ty p e o f bond

form ed; re s o n a n c e s t a b i l i z a t i o n ;
effect.

the s iz e ,

Increasing

in a decrease in s t a b i l i t y

S i n c e c h e l a t i n g a g e n t s a r e g e n e r a l l y Lewis b a s e s

a n d w i l l r e a c t w i t h L e w i s a c i d s , pH s h o u l d a l s o b e c o n s i ­
dered.

Hydrogen i o n w i l l compete w i t h m e ta l io n f o r t h e

c h e l a n t where th e s t a b i l i t y c o n s t a n t i s
m etal c h e la te s w ith h igh s t a b i l i t y
b y lo w pH.

low.

However, t h e

co n stan t are u n affected

E f f e c t i v e c h e l a t i o n a t h ig h pH 's depends

on t h e

s o l u b i l i t y p ro d u ct of th e hydroxide or a s s o c ia ti o n c o n s ta n t
of t h e h y d ro x id e com plex,
hydroxide i s

10

i.e.,

s o l u b i l i t y product of f e r r i c

a n d a t a pH o f 8 o r 9 i t b e c o m e s d i f f i ­

c u l t t o g e t good c h e l a t i o n

o f i r o n w i t h EDTA.

S o i l O rganic M a t t e r and C h e l a t i o n
Among t h e m e c h a n i s m s r e s p o n s i b l e f o r t h e c o m p l e x i n g
o f t h e m e t a l s by s o i l
co ag u latio n ,

organic m a tte r ,

ion exchange,

c h e l a t i o n and complex

surface adsorption,

tio n re a c tio n s are described

(M ortensen,

1963).

and p e p t i z a ­
Very l i t t l e

11
i s known c o n c e r n i n g t h e n a t u r e o f t h e l i g a n d s i n p o l y m e r i c
components o f o r g a n ic m a t t e r w hich c h e l a t e m e t a l s , b u t c a r ­
boxyl, carb o n y l, hydroxyl,

and amide g ro u p s a r e p r o b a b l y

involved.
A general c la s s ific a tio n
g iv e n by A l l i s o n ,
nic m atter is
"(l)

of s o i l organic m a tte r is

1965^ and A l l i s o n ,

et al.,

1965.

Th e o r g a ­

d iv id ed in to th e follow ing c a te g o rie s :

f r e s h p l a n t and a n im a l r e s i d u e c a p a b l e of r a p i d decom­

p o s i t i o n and l o s s
n u trien ts,
resistan t

(2)

of i d e n t i t y w ith sim ultaneous r e l e a s e

'hum us' w hich r e p r e s e n t s t h e v a s t b u l k of

organic m a tte r, having a h igh a d s o r p tiv e c a p a c ity

f o r c a t i o n s and c a p a b le o f im p ro v in g s o i l s t r u c t u r e ,
(3)

in ert

of

and

f o r m s o f n e a r l y e l e m e n t a l C, s u c h a s c h a r c o a l ,

c o a l or g r a p h i t e , which a r e o c c a s i o n a l l y p r e s e n t i n a p p r e ­
ciable q u a n titie s."
B roadbent (1953) 3 w h ile c o n s id e rin g th e c o n s t i t u e n t s
of p la n t t i s s u e as p re c u rs o rs
such c o n s t i t u e n t s
(l)

of s o il

i n t o more s p e c i f i c

polysaccharides,

(2) l i g n i n ,

organic m a tte r ,

groups

d iv is io n s as fo llo w s:

and (3 ) p r o t e i n .

M ore r e ­

c e n t s t u d y ( M e h t a et_ al_ 1 9 6 1 ) i n d i c a t e t h a t c a r b o h y d r a t e s
a c c o u n t f o r no more t h a n 2 0$ and p o l y s a c c h a r i d e s
2$ o f t h e s o i l

organic m a tte r.

less

than

P o lysaccharides are also

r e a d i l y a t t a c k e d and u t i l i z e d by t h e s o i l

organism s.

Because

of such s u s c e p t i b i l i t y to m ic ro b ia l a t t a c k th e p r i n c i p a l
s tr u c tu r a l p olysaccharides

of p la n ts a re th e re fo re not lik e ly

12
t o a c c u m u l a t e i n s o i l , w h e r e a s l i g n i n i s b r o k e n down o n l y
slow ly.

N evertheless d r a s tic a l t e r a t i o n tak es p la ce in p la n t

l i g n i n d u rin g th e co u rse of decom position in s o i l .
a c c o u n t s f o r 5% o f t h e s o i l
ganic n itro g e n i s

organic m a tte r.

Much o f t h e o r ­

i n t h e form o f p o l y p e p t i d e s and amino

a c i d s i n t i m a t e l y com plexed w i t h p o l y s a c c h a r i d e s ,
v ativ es,

and pigm ents

(Bremner,

lig n in d e ri­

1965).

In a d d itio n to th e in te rm e d ia ry products

of organic

m a t t e r breakdow n and s e c o n d a r y s y n t h e t i c p r o d u c t s
b ia l actio n ,

th ere e x ists

more r e s i s t a n t p r o d u c t s
Th e n a t i v e

N itrogen

of m icro­

i n s o i l an accu m u latio n of th e

of deco m p o sitio n :

organic f r a c t i o n

of s o i l s

t h e s o i l humus.

i s made up o f a h e t e r o ­

geneous m ix tu re of polym erized aro m a tic m o le c u le s , p o ly ­
s a c c h a r i d e s , bound amino a c i d s ,

u ro n ic a c id polym ers,

v a r i o u s o r g a n i c p h o s p h o ro u s compounds.
is

and

By d e f i n i t i o n humus

a complex m ix tu r e of amorphous and c o l l o i d a l s u b s t a n c e s

a r i s i n g from m o d i f i e d p l a n t m a t e r i a l s and s y n t h e s i z e d m i c r o ­
b ial

tissu e.

The c h a r a c t e r i z a t i o n

o f humus i s

c o m p le te and c o n c e p ts c o n c e rn e d w ith i t s
are,

to a larg e ex ten t,

speculative

f a r from

form ative p ro cesses

(Stevenson,

1 96 5).

M o r t e n s e n a n d Himes ( 1 9 6 5 ) r e c o u n t e d some d i f f i c u l ­
ties

a s s o c i a t e d w ith th e f r a c t i o n a t i o n and q u a l i t a t i v e

s tu d y of th e s o i l o rg an ic m a t te r .
c a n b e overcome.

Some o f t h e s e p r o b l e m s

Th e m o s t i m p o r t a n t i s

inorganic c o n stitu e n ts

such as c l a y ,

th e rem oval of

salts,

and m e ta ls i f

th e

13
physico-chem ical p ro p e rtie s
be s tu d ie d .

o f t h e o r g a n i c co m p o u n d s a r e t o

Th e a u t h o r s h a v e f u l l y d i s c u s s e d t h e v a r i o u s

procedures used fo r f r a c tio n a tio n

of organic m a tte r e x t r a c t s .

Such p r o c e d u r e s i n c l u d e p a r t i a l f r a c t i o n a t i o n

o f t h e c om po­

n e n ts i n o rg a n ic m a t t e r e x t r a c t s by p r e c i p i t a t i o n w ith a c id
or m etal s a l t s

or s o lu b ility d ifferen ces

chrom atographic s e p a r a tio n s
tio n

in organic s o lv e n ts ,

of crude p r e p a r a tio n s ,

o f s u b s t a n c e s b y me an s o f a n e l e c t r i c

cu rren t,

separa­
diffu­

s i o n and s e d i m e n t a t i o n .
S t u d i e s b y s e v e r a l r e s e a r c h e r s h a v e shown t h a t m o s t o f
th e p r i n c i p a l c h e l a t i n g donor groups a re p r e s e n t i n s o i l o r­
ganic m a tte r .

Such gro u p s i n c l u d e am ino, im in o , k e t o ,

hydroxy, t h i o e t h e r ,

carboxylate,

and p h o s p h o n a te g r o u p s .

Many l i g a n d g r o u p s p r o b a b l y f u n c t i o n l a r g e l y a s c e n t e r s
ionic

for

exch a n g e b u t c h e l a t i o n - t y p e r e a c t i o n no d o u b t o c c u r s

(M crtensen,

1963).

A lthough th e lig a n d groups i n polym ers

a r e n o t f r e e t o move a n d c l u s t e r a r o u n d a m e t a l i o n i n a
way s m a l l l i g a n d s b e h a v e , a n d m o r e o v e r t h e n u m b e r o f c h e l a t e
sites

a r e c o m p a r a t i v e l y s m a l l , a fe w l i g a n d g r o u p s s h o u l d b e

found i n a r r a y s which a r e s t e r i c a l l y

favorable fo r c h e la tio n .

S i d e c h a i n g ro u p s a r e u s u a l l y more e f f e c t i v e i n b i n d i n g
m e ta ls th a n th e te r m in a l groups

(Guard and W ilcox,

1956).

The s t u d y o f B l o o m f i e l d i n 1956 on t h e m o b i l i z a t i o n
o f i r o n i n p o d z o l s o i l s by a q u eo u s l e a f e x t r a c t s

suggests

t h a t t h e p o ly m e ric components o f o rg a n ic m a t t e r c h e l a t e

14
m etals.

B lo o m fie ld re c o g n iz e s p o ly p h e n o ls as b e in g th e

p r i n c i p a l c h e l a t o r s i n aqueous l e a f e x t r a c t s .

S chnitzer

( 1 9 5 4 ) a n d S c h n i t z e r a n d DeLong ( 1 9 5 5 ) h a v e i n d i c a t e d t h e
considerable c h e la tin g a b i l i t y
l e a f e x tra c t's .

of poly sacch arid es

in aqueous

T h e s e co mp ou nd s a r e a l s o f o u n d t o b e a c o n s ­

titu e n t part

of fu lv ic a cid .

hydrolyzates

of s o i l

The p r e s e n c e o f a m i n o a c i d s i n

organic m a tte r and th e c h e l a t i n g a b i l i t y

o f p r o t e i n s a s w e l l a s a n u m b e r o f l o w m o l e c u l a r w e i g h t com­
pounds has b e en c o n firm e d by a number of i n v e s t i g a t o r s
(M ortensen,

1 9 6 3 )-

A ll such s tu d ie s su g g est th e c h e la tio n

r e a c t i o n a s on e o f t h e m e c h a n i s m s b y w h i c h o r g a n i c m a t t e r
forms com plexes i n s o i l .

However, i n a more s p e c i f i c

study

S c h n i t z e r and S k in n e r ( 1963) i n v e s t i g a t e d t h e r e a c t i o n s b e ­
tween a number o f m e t a l io n s and t h e o r g a n i c m a t t e r o f a
p o d z o l Bh h o r i z o n .
titratio n ,

U sin g p o t e n t i o m e t r i c and c o n d u c to m e tr ic

a d s o r p t i o n and i n f r a r e d s p e c tr o s c o p y and f l o c c u ­

l a t i o n m ethods,

th ey concluded t h a t th e o rg an ic m a tte r

formed s t a b l e w a te r s o l u b l e com plexes w i th a l l
stu d ied

of th e m etals

( F e + + + , A l + + + , Ca++, Mg**, Cu+ + , a n d N i + + ) o v e r t h e

pH r a n g e e n c o u n t e r e d i n p o d z o l s o i l s .

F erric iro n ,

aluminum

a n d c o p p e r f o r m e d w a t e r s o l u b l e 1 : 1 m o l a r c o m p l e x e s a t pH 5 .
However, a r a n g e o f m o l a r co m p le x es v a r y i n g from 1 :1 t o 6 : 1
w ere form ed and t h e com plexes w ere i n c r e a s i n g l y r e n d e r e d
w a t e r i n s o l u b l e a s m o r e m e t a l was c o m p l e x e d .

The n u m b e r -

average m o le c u lar w eight of organic m a tte r used i n t h i s

15
s t u d y i n tw o d i f f e r e n t s o l v e n t s was f o u n d t o b e 6 7 0 , a n d
from t h e m o l e c u l a r w e i g h t and from u l t i m a t e and f u n c t i o n a l
group a n a l y s i s ,

th e m o le c u la r form ula c a l c u l a t e d t o be

C2 i H i 2 (C 00 H )6 ( 0 H ) 5 ( C 0 ) 2 .
The same a u t h o r s

( S c h n it z e r and S k in n e r,

1963),

in a

su b seq u en t s tu d y of th e r e a c t i o n s betw een d i f f e r e n t forms of
i r o n a n d a l u m i n u m a n d t h e o r g a n i c m a t t e r o f t h e p o d z o l Bh
horizon,

s h ow e d t h a t

on c o n t i n u o u s w e t t i n g a n d l e a c h i n g i n a

p e r i o d o f one w e e k on e m o l e o f o r g a n i c m a t t e r m o b i l i z e d one
mole o f i r o n from g o e t h i t e and an i r o n s a t u r a t e d e x change
resin ,

and 1 .1 m ole o f aluminum from aluminum s a t u r a t e d e x ­

change r e s i n .

Th e m e t a l u p t a k e i n r e a c t i o n w i t h g o e t h i t e

a n d g i b b s i t e w as d e c r e a s e d w i t h a n i n c r e a s e i n pH.

Th e me-

t h y l a t i o n of most of th e a c t i v e a c id groups reduced i r o n
uptake i n d i c a t i n g th e im p o rta n t r o l e of carb o x y l groups in
the

o rgano-m etallic re a c tio n s .
S c h n i t z e r and S k i n n e r ( 1 9 6 6 ) c a r r i e d

the s t a b i l i t y
com plexes.

on a s t u d y o f

c o n s t a n t o f Cu+ + , F e + + , a n d Zn++ f u l v i c

The r e s u l t s

acid

o b t a i n e d show t h a t t h e l o g K v a l u e s

f o r C u - f u l v i c a c i d c o m p l e x e s w e r e pH d e p e n d e n t , t h a t i s ,
t h e s e v a l u e s w e r e i n c r e a s e d f r o m 5 * 7 8 t o 8 . 6 9 a s pH was i n ­
c r e a s e d from 3 -5 t o 5 -

A s l i g h t i n c r e a s e was o b s e r v e d f o r

Z n - f u l v i c a c i d c o m p l e x e s w h i l e t h e Fe + + - f u l v i c
were u n a f f e c t e d .

The o r d e r o f s t a b i l i t i e s

formed betw een f u l v i c

a c i d com plexes

o f com plexes

a c i d a n d C u " ^ , Zn+ + , a n d Fe"1^" d i d n o t

16

+
>

f o l l o w t h e I r v i n g - W i l l i a m s s e r i e s h u t was i n s t e a d Cu
+4\
I.
Fe
Zn • I n a l a t e r a t t e m p t t o e v a l u a t e t h e m e t h o d s f o r
the d e te rm in a tio n of s t a b i l i t y c o n sta n ts

of m e ta l- f u lv ic

a c i d c o m p le x e s , S c h n i t z e r and Hansen ( 1 9 7 0 ) fo u n d t h e f o l l o w ­
i n g o r d e r of' s t a b i l i t i e s
F e ^ d

a t lo w pH:

Al+++>

An i n c r e a s e i n i o n i c

Cu+t >

stren g th

a r e more r e l e v a n t

(stab ility

f o r Co+ + - f u l v i c

The a u t h o r s b e l i e v e t h a t s t a b i l i t y
(u)

Co+j >

Pb++

( u ) a t a pH a s lo w a s 3 c a u s e d

a l i n e a r d e crea se in log K v alu es
T h i s was e s p e c i a l l y t r u e

Ni++>

to s o i l s

co n stan ts).

a c id com plexes.

c o n s t a n t s m e a s u r e d a t low

th a n th o se determ ined a t

higher (u).
S c h n i t z e r and D e s ja r d in s

( 1969) stu d ie d th e n a tu r a l

l e a c h a t e f r o m a h u m id p o d z o l a n d a n a l y z e d i t b y c h e m i c a l a n d
s p e c tro s c o p ic m ethods.

About 87$ of th e d r y ,

o f t h e l e a c h a t e was f o u n d t o b e f u l v i c a c i d ,
c o n s is tin g m ainly of p o ly s a c c h a rid e s

a s h - f r e e w eight
th e rem ainder

and n i t r o g e n o u s compounds.

The o r g a n i c m a t t e r i n t h e l e a c h a t e h a d a l l t h e c h a r a c t e r i s t i c s
o f a n e f f i c i e n t irn. d - c o m p l e x i n g a g e n t ,
high w ater s o l u b i l i t y ,

as e v id e n c e d from i t s

thus p la y in g a s i g n i f i c a n t r o le in

m etal organic m a tte r i n t e r a c t i o n s

in s o ils .

17
E x t r a c t i o n of O rg an ic M a t t e r from S o i l s
M o r t e n s e n a n d Himes
tio n procedures

of s o i l

( 1 ) proxim ate a n a ly s is ,
clay ,

( 1965) have review ed th e e x t r a c ­

organic

m a tte r as fo llo w s:

( 2 ) a d s o r p t i o n o f o r g a n i c m a t t e r on

( 3 ) organo-m ineral g e ls ,

(4) aqueous e x t r a c t a n t s

and

ch elatin g e x tractan ts.
The p r o x i m a t e a n a l y s i s

in v o lv e s a t t r a c t i o n betw een

s o l u t e a n d s o l v e n t a n d g i v e s some g e n e r a l i n f o r m a t i o n on t h e
q u a n tity of d i f f e r e n t c la s s e s

o f compounds.

d i f f e r e n t i a l s o l u b i l i t y problem s,

In a d d itio n to

a d s o rp tio n of organic

m a t t e r on t h e s u r f a c e o f s o i l m i n e r a l s , p a r t i c u l a r l y c l a y
m i n e r a l s , make t h e e x t r a c t i o n

of organic m a tte r d i f f i c u l t .

Some o r g a n i c m o l e c u l e s a r e a p p a r e n t l y h e l d t o t h e c l a y s u r ­
fa c e through C -H ...0

( clay -m in eral su rfa ce ) bonds,

although

any s o r b a t e c a p a b le o f s u p p ly in g e l e c t r o n s t o t h e in c o m p le te
P o rb itals

of adsorbed or l a t t i c e

aluminum c o u l d b e a d s o r b e d .

Compounds c o n t a i n i n g e l e c t r o - n e g a t i v e e l e m e n t s may b e
a d s o r b e d by a h y d ro g e n b o n d in g m echanism.

N egatively

c h a rg e d o rg a n ic a n io n s and p o ly a n io n s a r e a p p a r e n t l y l i n k e d
t o t h e c l a y s u r f a c e t h r o u g h p o l y v a l e n t i n o r g a n i c c a t i o n s and
io n iz e d c arb o x y l groups
adsorbed,
tioned.

(clay-M -OOCR).

Among t h o s e c a t i o n s

a lu m i n u m o r i r o n h y d r o x i d e p o l y m e r s c a n b e m e n ­
It

a p p e a r s t h a t t h e r e a g e n t s w h ic h decompose t h e

clay l a t t i c e ,

such as p h o s p h a te ,

flu o rid e,

s t r o n g b a s e and

h y d r o f l u o r i c a c i d may b e m o s t u s e f u l f o r o r g a n i c m a t t e r
ex tractio n .

18
O rgano-m ineral c o l l o i d s
th o se o c c u rrin g as a r e s u l t
w i t h aluminum and i r o n ,

in the s o i l ,

p articu larly

of i n t e r a c t i o n of organic m a tte r

can be t r a n s f e r r e d i n t o w a te r - s o l u b le

h y d r o x y c o m p l e x e s i n a s l i g h t l y a l k a l i n e m e d iu m , w h i l e a
s t r o n g l y a l k a l i n e med ium may c o m p l e t e l y h y d r o l y z e t h e m .
The p r e s e n c e o f f r e e m o n o m e r i c f o r m s o f o r g a n i c m o l e ­
cules

s u c h a s amino a c i d s a n d h y d r o c a r b o n s n e c e s s i t a t e s

rem oval i n o rd e r t o i n c r e a s e t h e e f f i c i e n c y

th eir

of e x tr a c ti o n .

Such p r e t r e a t m e n t p ro c e d u r e s i n c l u d e t h e u s e o f o rg a n ic r e ­
a g e n ts such as b e n z e n e , m e th a n o l, c h lo r o f o r m , and e t h a n o l ,
w e ll as b a l l - m i l l i n g t h e s o i l and s u l f a c e t o l y s i s
tric

f r a c t i o n a t i o n t o remove t h e " u n h u m ifie d "

m aterial.

as

or densim e-

or unadsorbed

H y d r o f l u o r i c a c i d - h y d r o c h l o r i c a c i d m ix tu r e s and

d e c a l c i f i c a t i o n w i t h 0 . 1 N h y d r o c h l o r i c a c i d h a v e i n some i n s ­
tan ces in c re a se d the e ff ic ie n c y
Himes,

of e x tra c tio n

(M ortensen and

1 9 6 5 )Aqueous i n o r g a n i c and o r g a n i c e x t r a c t a n t s h a v e b e e n

w idely used to e x t r a c t s o i l

organic m a tte r.

Th e s u c c e s s f u l

u se of n a t u r a l and s y n t h e t i c c h e l a t i n g a g e n ts t o e x t r a c t
m e t a l s a n d o r g a n i c m a t t e r f r o m s o i l a r e t o some d e g r e e i n d i ­
cativ e

of th e c ir c u m s t a n tia l evidence t h a t m etals a re c h e la ­

t e d by o rg a n ic m a t t e r .
S e v e ra l re s e a rc h e r s have used c h e la tin g a g en ts to
desorb the m ic ro n u trie n ts
able to p la n ts .

f r o m t h e s o i l a n d make t h e m a v a i l ­

D i o n a n d Mann ( 1 9 4 6 ) h a v e sh own t h a t n e u t r a l

19
sodium and p o t a s s i u m p y r o p h o s p h a t e s ,

a s e x t r a c t a n t s f o r m a n­

g a n e s e , a r e much m o r e e f f e c t i v e t h a n t h e c o r r e s p o n d i n g o r t h o ­
p h o s p h a te s and t h a t a s o l u b l e complex o f m a n g a n i-p y ro p h o s p h o ric

a c i d H(MnP2 0 y ) h a s b e e n i d e n t i f i e d

in the b u ffered pyro­

p h o s p h a te i n which manganese h as a v a le n c e of 3.

H e i n t z and

Mann ( 1 9 ^ 7 ) i n d i c a t e t h a t v a r i o u s o r g a n i c h y d r o x y - a c i d s a r e
a lm o s t as e f f e c t i v e as p y r o p h o s p h a t e and more e f f e c t i v e t h a n
t h e c o rr e s p o n d in g u n s u b s t i t u t e d a c id s as s o i l manganese ex­
tractan ts.

K a nw a r ( 1 9 5 * 0 w as a b l e t o c o r r e c t t h e c o p p e r d e ­

f i c i e n c y c a u s e d by f i x a t i o n by paddy s o i l s
m atter content.

high in o rg an ic

Sodium v e r s e n a t e and sodium p y r o p h o s p h a t e

a p p e a r e d t o be s a t i s f a c t o r y com plex fo rm in g a g e n t s .
and S h a rm a 's

( 1961) experim ental r e s u l t s

M isra

re v e a l th a t the

.j,

Cu

io n s a r e a d so rb e d from c o p p e r s u l p h a t e s o l u t i o n by s o i l s

and com post a l i k e , b u t t h e a d s o r p t i o n g r e a t l y depends upon
CaCO^ c o n t e n t a n d pH o f t h e m a t e r i a l a n d t h a t t h e a d s o r b e d
Cu++ i s

read ily

e x t r a c t e d by o rg a n ic a c i d s .

E x p e rim en ts u s i n g t h e s o l u b l e component of p l a n t r e ­
s id u e s as w e ll as anim al b y p ro d u c ts as e x t r a c t a n t s
elem en ts have b een c o n d u cte d by s e v e r a l s c i e n t i s t s .
( 1949) has d e m o n stra te d th e a b i l i t y

of tra c e
H urw itz

of s o l u b l e components of

a l f a l f a m e al and o a t s t r a w t o i n c r e a s e t h e amount o f c o p p e r
l e a c h e d from a s a n d y loam and s i l t y

c l a y loam s o i l .

He a l s o

i n d i c a t e s t h a t t h e amount o f c o p p e r l e a c h e d from t h e s o i l i s
d i r e c t l y p r o p o r t i o n a l t o t h e amount o f p l a n t r e s i d u e u s e d .

20

F u r t h e r m o r e , he c o n c lu d e s t h a t t h e c o p p e r w hich e x i s t s
m e t a l o - o r g a n i c complex i s

in

t h e form a f f e c t e d by t h e s o l u b l e

components of t h e p l a n t r e s i d u e .
M i l l e r and O hlrogge (1 9 5 8 ),
of c h e la te -c o n ta in in g m a te ria ls
m etals

to p la n ts ,

i n a s t u d y of i n f l u e n c e

on t h e a v a i l a b i l i t y

have observed a r e d u c tio n i n a b s o r p tio n

Zn a n d Fe by p l a n t s u p o n a d d i t i o n o f w a t e r - e x t r a c t s
y a r d manure t o n u t r i e n t s o l u t i o n s .

was a p p l i e d t o t h e s o i l .

of b a r n ­

o f Zn a n d Cu when i t

I t was c o n c l u d e d t h a t t h e c h e l a t i n g

agents h eld the m ic ro n u trie n ts

i n a l e s s a v a i l a b l e form.

M at o m u ra ( 1 9 6 1 ) r e c o g n i z e d t h a t t h e e x t r a c t s
m i l k v e t c h had a f a i r l y

of

They a l s o n o t i c e d t h a t

such e x t r a c t s d e c re a se d th e a v a i l a b i l i t y

from

high d i s s o l u t i o n c a p a c ity f o r b o th

i n s o l u b l e i n o r g a n i c i r o n com po un ds a n d i r o n i n s o i l .
d i s s o l v e d i r o n was m a i n l y i n f e r r i c
of the t o t a l

of trace

The

forms and o n ly 2 0 - 40$

d i s s o l v e d i r o n was i n f e r r o u s

form.

He a l s o

n o t i c e d t h a t t h e d i s s o l v i n g c a p a c i t y f o r a l u m i n u m was much
less

than fo r iro n .

F u rth e rm o re , he co n clu d ed t h a t f a t t y

a c i d s and com plex c h e l a t i n g m a t e r i a l s i n e x t r a c t s w ere r e s ­
p o nsible fo r d is s o lu tio n
ferric

of i r o n and r e d u c t i o n

of d is so lv e d

i r o n was d u e t o some r e d u c i n g s u b s t a n c e s w h i c h w e r e

formed d u r i n g t h e f e r m e n t a t i o n p r o c e s s .
The r e s u l t s

of s t u d i e s by a number of r e s e a r c h e r s

have r e v e a le d t h a t th e i l l u v i a l
zon of p o d z o l i c

so ils

is

organic m a tte r in th e B h o r i ­

e a s ie r to e x tr a c t th a n th e organic

21
m atter in the su rface s o i l .
sib ility

of the p r e c ip ita tio n

Such d a t a a l s o s u g g e s t t h e p o s ­
or f l o c c u l a t i o n of organic

m a t t e r by i r o n a n d aluminum i n t h e s e s o i l s ,

and t h a t com plex-

in g th e s e m eta ls re n d e rs th e o rgan ic m a tte r s o lu b le in w a te r.
A v ariety

o f n a t u r a l and s y n t h e t i c

organic c h e la tin g agents

as w e ll as in o r g a n i c r e a g e n ts have been u sed t o e x t r a c t b o th
th e

o r g a n ic m a t t e r from t h e s u r f a c e and s u b s u r f a c e l a y e r s

of

podzolic s o i l s .
An e x t e n s i v e r e v i e w c o n c e r n i n g t h e s o l u b i l i z i n g e f f e c t
of n a tu r a lly

o c c u r r i n g compounds,

s i z e d by p l a n t c e l l s ,
salts

such as m a t e r i a l s y n th e ­

e . g . , ADP, a s w e l l a s o t h e r n a t u r a l

of o rg an ic and in o rg a n ic a c id s

in n a tu re ,

on t h e i n s o l u b l e m a t t e r

can be found i n a r t i c l e s by M andle, G ra u e r ,

Neuberg (1952 and 1 9 5 3 ).

The a u t h o r s c o n s i d e r a n u m b e r o f

such n a t u r a l l y

o c c u r r i n g c om po un ds a s b e i n g " o b l i g a t o r y

in te rm e d ia tes,

c o n tin u a lly reform ed,

m etabolism ,

and

or f in a l products

of

or c e l l u l a r c o n s t i t u e n t s ."

S ynthetic

o rg an ic c h e l a t i n g ag en ts have been used to

e x t r a c t m e t a l s complexed by s o i l o r g a n ic m a t t e r w i t h a s u b s e ­
quent d is p e rsio n of s o il

organic m a tte r.

M a r tin and Reeves

( 1 9 5 7 ) have u s e d a number o f o r g a n i c c h e l a t i n g a g e n t s i n
d e alin g w ith podzolic i l l u v i a l h o rizo n s.
resu lts

T heir experim ental

r e v e a l t h a t a c e t y l a c e t o n e a p p e a rs t o be th e most s a t i s ­

f a c t o r y r e a g e n t and r e a d i l y forms com plexes w ith t r a n s i t i o n a l
m etals.

Th e c h e l a t e s

o f A1 a n d Fe w i t h a c e t y l a c e t o n e a r e

22
extrem ely s t a b l e w ith o v e r a ll fo rm atio n c o n sta n ts
o f 2 2 .3 and 2 6 .2 r e s p e c t i v e l y .

C upferron,

(o r log
another

o r g a n i c r e a g e n t t h e y u s e d i n t h e i r s t u d y , was n o t s a t i s f a c ­
t o r y as an e x t r a c t a n t .

N e i t h e r w as t h e o x i n e , w h i c h p r o v e d

t o be a slow e x t r a c t o r .

T he y c o n c l u d e d t h a t e v e n i f

m e ta l c o o r d i n a t i o n com plexes e x i s t i n t h e s e s o i l s ,

ex tractio n

of o rg a n ic m a t t e r would be g o v e rn e d by o t h e r f a c t o r s
pH a n d t h e n a t u r e

such as

of the c a tio n a s s o c ia te d w ith th e re a g e n t.

I n a s u b s e q u e n t s tu d y M a r tin and Reeves (1957)
on t h e e f f e c t

true

report

of th e c o n c e n tr a tio n of aqueous a c e ty la c e to n e

a s w e l l a s t h e e f f e c t o f e x t r a c t i o n t i m e a n d pH on t h e e x ­
tractio n
clearly
tractio n

o f o rg a n ic carb o n and s e s q u i o x i d e s .
show t h a t r e a c t i o n t i m e h a s l i t t l e

T heir d ata

in flu en ce

on e x ­

of carbon, w h ile in c r e a s in g re a g e n t c o n c e n tra tio n

c a u s e s an i n c r e a s e in c a r b o n d i s p e r s i o n .

A l s o , °.2M a c e t y l a c e ­

t o n e a t pH 7 r e m o v e s m o r e c a r b o n a n d i n some c a s e s m o r e A1
c o m p l e x e s t h a n a t pH 4 . 2 , b u t l e s s F e i s
pH.

F urtherm ore,

the s u p e rio rity

t y l a c e t o n e was c o n f i r m e d .
these fin d in g s
lity ,

in term s

log c o n sta n ts

low.

is d i f f i c u l t to explain

of c h e la te s t a b i l i t y

(o v er-all s ta b i­

of C u -p y ro p h o s p h a te and C u - a c e t y l a c e t o n e

r e a l e x p l a n a t i o n may l i e

tio n is

of pyrophosphate over a c e ­

W hile i t

a r e 1 0 .1 and 1 7 .4 r e s p e c t i v e l y ) ,

a t pH 7 c o n t a i n s

e x tra c te d a t higher

th e authors suggest th a t the

in the fa c t th a t the a ce ty la ce to n e

o n l y 1 - 2 $ f r e e a n i o n a n d t h e Na+ c o n c e n t r a ­

Th u s m e t a l s r e m o v e d f r o m t h e o r g a n i c m a t t e r a r e

23
r e p l a c e d p r e d o m i n a n t l y b y H+ .
io n izatio n is

W i t h ^ 2^ 2 2 0 7 s t h e d e g r e e o f

la r g e and a l a r g e r f r a c t i o n

g r o u p s on t h e o r g a n i c m a t t e r s u r f a c e i s

of the a c tiv e

o c c u p ie d by Na, r e ­

su ltin g in g re a te r d isp ersio n .
O ther o rg a n ic com plexing r e a g e n ts

such as 8 -h y d ro x y -

q u in o lin e , disodium dihydrogen e th y le n e d ia m i n e t e tr a a c e t ic
acid,

cupferron,

acetylacetone,

as w e ll as th e in o rg a n ic

c h e l a t i n g a g e n t N a -p y ro p h o sp h a te , w ere u se d t o e x t r a c t o rg a ­
n i c m a t t e r from s o i l by C houdhri and S t e v e n s o n ( 1 9 5 7 ) .
s tu d ie d the e f f e c ts

They

of p r e t r e a t m e n t and e x ch a n g e a b le b a s e s ,

rem o v al o f f r e e i r o n and aluminum o x i d e s ,
val of s i l i c a t e m inerals

on t h e

and f i n a l l y ,

remo­

organic m a tte r e x tr a c ti o n .

Th ey c o n c l u d e d t h a t t h e r e m o v a l o f c a l c i u m a n d f r e e i r o n a n d
aluminum o x i d e s i n c r e a s e d t h e s o l u b i l i t y

of organic m a tte r

b y a l m o s t a l l t h e r e a g e n t s t h e y u s e d , b u t h a d n o e f f e c t on
e x t r a c t i o n by p y ro p h o sp h a te .
c a t e m i n e r a l s was e f f e c t i v e

However, t h e re m o v a l o f s i l i ­
in f a c i l i t a t i n g the e x tra c tio n

o f h u m ic a c i d b y p y r o p h o s p h a t e a s w e l l a s o t h e r c h e l a t i n g
agents used in th e study.
P arso n and T i n s l e y

( i 9 6 0 ) have used form ic a c i d ,

p o l a r compound, as an e x t r a c t a n t f o r s o i l
p a rtic u la rly polysaccharides.
advantages

of th e s o lv e n t i s

or h y d r o ly tic p r o p e r t i e s

a

organic m a tte r,

They s t a t e t h a t
the la c k of e ith e r

one o f t h e
o x idizing

in th e anhydrous c o n d itio n .

T he y

a l s o n o t e d an i n c r e a s e i n e x t r a c t i o n e f f i c i e n c y upon a d d i t i o n
of in o rg a n ic c a tio n s to th e e x t r a c t a n t .

24
In o rg an ic re a g e n ts have been w idely used to e x t r a c t
so il

o r g a n i c m a t t e r w i t h some s u c c e s s .

(1946) h ave u s e d p y r o p h o s p h a t e ,
sodium s a l t s
late

Brem ner, e t a l . ,

orthophosphate,

a n d some

o f o r g a n i c co m p o u n d s s u c h a s c i t r a t e

as e x t r a c t a n t s

upon d i a l y s i s

of organic m a tte r.

and oxa­

They n o t i c e d t h a t

of th e pyrophosphate e x t r a c t th e w a te r - s o lu b le

o r g a n i c n i t r o g e n i s n o t removed w h i l e m o st o f t h e m e t a l s a r e
removed.

T heir r e s u lts

fu rth er in d icate th a t,

on t h e w h o l e ,

t h e co mp ou nds t h a t a r e g o o d p o l y v a l e n t c a t i o n e x t r a c t a n t s
a r e a l s o good o r g a n i c m a t t e r e x t r a c t a n t s .
part

of the p o ly v a le n t m etals i s

com plexes w ith p a r t

uble in w ater.

combined a s c o - o r d i n a t i o n

of th e organic m a tte r,

of th e m etals re n d e rs

They i n f e r t h a t

and t h e p r e s e n c e

o r g a n ic m a t t e r i n t h e com plexes i n s o l ­

They a l s o i n d i c a t e t h a t t h e e x t r a c t i n g power

o f 2% N a - h y d r o x i d e i s p r i m a r i l y d u e t o d e g r a d a t i o n o f t h e
h i g h m o l e c u l a r w e i g h t co mp ou nd s i n i t i a l l y

p resen t in the

so il.
Bremner and Lees

(19^9) f u r t h e r i n v e s t i g a t e d th e

q u e s tio n w hether th e s o l u b i l i t y
by th e n a t u r e
m etals,

of o rgan ic m a tte r i s governed

o f th e a s s o c i a t i o n betw een o rg a n ic m a t t e r and

as w e ll as th e a b i l i t y

of th e anion of th e e x t r a c t ­

a n t t o remove t h e i n t e r f e r i n g m e t a l s as e i t h e r i n s o l u b l e
p recip itates

or s o lu b le c o o r d in a tio n com plexes.

accom panying c a t i o n s u sed i n t h e e x t r a c t a n t s ,

Among t h e
+
Na , K , a n d
+

NH^ g a v e r i s e t o a n e f f i c i e n t e x t r a c t i o n , w h i l e Ca p r o v e d t o

25
be a c h ie f i n t e r f e r a n t in
above s t u d i e s

organic m a tte r e x tr a c ti o n .

In the

o r g a n i c n i t r o g e n was t a k e n a s a n i n d e x f o r s o i l

organic m a tte r.

However, i n a s u b s e q u e n t s t u d y , Brem ner

( 19^ 9 ) fo u n d t h a t t h e o r g a n i c c a r b o n and n i t r o g e n a r e i n t i ­
m ately a s s o c ia te d so t h a t th e organic carbon i s d is s o lv e d
only i n p r o p o r tio n to o rg a n ic n i t r o g e n .
D ilu te inorganic

a cid s have been used to e x t r a c t

or­

g a n ic m a t t e r from t h e p o d z o l i c s o i l s by S c h n i t z e r and W rig h t
(1957).

Two p e r c e n t o f t h e c a r b o n o f t h e Ao h o r i z o n a n d a s

h i g h a s 96/0 o f t h e c a r b o n o f a B h o r i z o n o f a p o d z o l s o i l
w e r e e x t r a c t e d b y HF, HC1, a n d a m i x t u r e o f HC1-HF.
c o n c e n t r a t i o n h i g h e r t h a n 0 . 5 $ was l e s s

effectiv e.

An a c i d
The

a m o u n t o f c a r b o n e x t r a c t e d b y 0 . 5 $ HC1 s h o w e d a c o r r e l a t i o n
w i t h e x t r a c t e d Fe a n d A l , w i t h ma xim a o c c u r r i n g i n t h e B
horizon e x tr a c ts .
I n a l a t e r s tu d y by S c h n i t z e r ,

et a l .,

s u rv e y o f th e e x t r a c t i v e power o f f i f t e e n
was m a d e .

( 1958),

in o rg an ic reagents

I n c l u d e d among t h e m w e r e NaOH, Na4 P2 0 y ,

NaF, a n d N a C l.

a

Na^PO^,

The o n l y o r g a n i c r e a g e n t u s e d was Nag-EDTA.

The pH r a n g e d f r o m 1 . 4 t o 1 3 . 1 ,

and t h e amount o f o r g a n ic

m a t te r e x t r a c t e d v a r ie d w ith h o riz o n as w e ll as w ith th e e x ­
tractan t.

T he y c o n c l u d e d t h a t w h i l e o n l y NaOH r e m o v e d

a p p r e c i a b l e a m o u n t s o r o r g a n i c m a t t e r f r o m t h e Ao h o r i z o n ,
o t h e r s s u c h a s Na2| P 2 0 y , Na^PO^, NaF, NagCO^, a n d EDTA, e x ­
t r a c t e d m o r e t h a n 8 0 $ o f t h e o r g a n i c m a t t e r i n t h e Bg^
horizon.

26
Evans (1959) n o t e d t h a t t h e e x t e n t o f o r g a n ic m a t t e r
e x t r a c t i o n t e n d e d t o r i s e w i t h t h e pH o f t h e e x t r a c t i n g s o l u ­
tio n .

The c h e l a t i n g r e a g e n t s e x t r a c t e d m o r e o r g a n i c m a t t e r

than o th er e x t r a c ta n ts

o f c o m p a r a b l e pH, b u t e x t r a c t s b y a l l

r e a g e n t s r o s e w i t h i n c r e a s i n g ti m e and t e m p e r a t u r e .
and Salam ( 1 9 6 1 ) a l s o c o n firm e d t h e s u i t a b i l i t y
p h o sp h a te as w e ll as c i t r a t e ,

o xalate,

T insley

of N a-pyro-

a n d s u l p h a t e a t com­

p a r a b l e c o n c e n t r a t i o n a n d pH v a l u e s f o r o r g a n i c m a t t e r e x ­
tractio n .

The r o l e

o f pH was a l s o s t u d i e d b y t h e a b o v e

a u t h o r s a n d i t was i n a g r e e m e n t w i t h E v a n ' s p r e v i o u s l y m e n­
tioned stu d ie s.
I t h a s b e e n d e m o n s t r a t e d t h a t s e c o n d a r y Fe a n d A l
co mp ou nds a n d o r g a n i c m a t t e r i n s o i l r e f l e c t p r o c e s s e s

of

s o i l f o r m a tio n and i n f l u e n c e s o i l s t r u c t u r e and p l a n t n u ­
trien t

statu s.

Fe a n d A l e x i s t i n d i f f e r e n t f o r m s i n s o i l ,

p a rtic u la rly in c ry s ta llin e
hydrous o x id e s,

o x id e s and s i l i c a t e s ,

amorphous

and as com plexes w i t h o rg a n ic m a t t e r .

form i n w hich t h e y a p p e a r i s

a diagnostic

fe a tu re of the B

h o r i z o n o f p o d z o ls and of im p o r ta n c e i n i d e n t i f i c a t i o n
the podzolic s o i l s .

The

of

A c o l l e c t i v e term of " a c tiv e " m a t e r i a l

h a s b e e n a s s i g n e d t o t h e c o l l o i d a l humus a n d s e s q u i o x i d e s
com plexes i n d i c a t i v e

of h ig h c a t i o n exchange c a p a c i t y and

physico-chem ical p r o p e r tie s .

T h e r e f o r e many r e s e a r c h e s h a v e

been conducted to d e sig n a sim ple e x t r a c t i o n te c h n iq u e to
s e p a r a t e t h e a c t i v e f r o m i n a c t i v e co mp ounds a n d c o m p l e x e s

27
w ith th e

o b j e c t o f im p ro v in g t h e i d e n t i f i c a t i o n and c l a s s i ­

ficatio n

of podzols.

F o r some t i m e f r e e F e o x i d e s h a v e b e e n e x t r a c t e d f r o m
s o i l s by d i t h i o n i t e - c i t r a t e - b i c a r b o n a t e
(M e h ra a n d J a c k s o n ,

i 960).

ex tractin g so lu tio n

McKeague a n d Day ( 1 9 6 6 ) made a

com parison of th e e x t r a c t a b i l i t y

o f i r o n and aluminum w i t h

d i t h i o n i t e a n d a c i d ammonium o x a l a t e , u s i n g some C a n a d i a n
podzolic

so ils.

T heir r e s u lts

tractio n

d i s s o l v e d much o f t h e i r o n a n d a l u m i n u m f r o m t h e

amorphous m a t e r i a l s ,

rev eal th a t the o x alate ex­

i n c l u d i n g t h e amorphous h y d ro u s o x id e s

o f r e c e n t w e a t h e r i n g as w e l l as m e t a l - o r g a n o c o m p le x es, b u t
very l i t t l e
d ith io n ite

from c r y s t a l l i n e

oxides.

On t h e o t h e r h a n d ,

the

e x tra c tio n disso lv ed a la rg e p ro p o rtio n of c ry s ­

ta llin e

iro n oxides,

a s w e l l a s much o f t h e a m o r p h o u s m a t e ­

rials.

They a l s o n o t i c e d t h a t o x a l a t e - e x t r a c t a b l e Al f r e ­

q u e n tly exceeded d i t h i o n i t e - e x t r a c t a b l e A l,

and t h e r a t i o

of

o x a l a t e t o d i t h i o n i t e - e x t r a c t a b l e F e commonly was h i g h f o r B
horizons.

Th ey c o n c l u d e d t h a t s i n c e o x a l a t e e x t r a c t s

and Al o r g a n i c com plexes from s o i l ,
e x t r a c t e d by o x a l a t e from B h o r i z o n s
m etal-organic

iro n

some o f t h e Fe a n d A l
o f p o d z o ls e x i s t e d as

com plexes.

F ranzm eier,

et_ a l . ,

( 1 9 6 5 )5 u s e d a m i x t u r e o f p y r o ­

p h o s p h a t e a n d d i t h i o n i t e i n s o l u t i o n a t pH 7 . 3 t o e x t r a c t F e ,
A l , and o r g a n ic C from p o d z o l B h o r i z o n s .

However, d i t h i o ­

n i t e d i s s o l v e s Fe s i l i c a t e m i n e r a l s a n d a m o r p h o u s Fe o x i d e s .

28
T itova

( 1 9 6 2 ) h a s shown t h a t n e u t r a l s o d i u m p y r o p h o s p h a t e i s

c a p a b le o f e x t r a c t i n g i r o n from h y d ro x id e as w e l l as i r o n con
ta in in g m inerals.
d icates

F u r t h e r d a t a b y Kon onova* e t a l . ( 1 9 6 4 ) *

t h a t t h e n e u t r a l sodium p y r o p h o s p h a te i s

in

rath er a

s t r o n g r e a g e n t w hich decomposes m i n e r a l s and f r e e s t h e i r o n
and aluminum.

Therefore,

t h e above a u t h o r s do n o t c o n f i r m

th e h y p o th e sis t h a t th e pyrophosphate s o lu tio n e x t r a c t s

only

t h e Fe a n d A l f i x e d b y o r g a n i c s u b s t a n c e s .
McKeague ( 1 9 6 7 ) c o m p a r e d F r a n z m e i e r ' s
tio n ,

ex tractin g so lu ­

O.lM N a - p y r o p h o s p h a t e a n d 0.2M a c i d i f i e d ammonium o x a ­

l a t e as e x tr a c ta n ts

of th e accum ulation p ro d u c ts in po d zo ls.

His d a t a s u g g e s t t h a t

o.lM N a - p y r o p h o s p h a t e s o l u t i o n e x t r a c ­

t e d some o f t h e F e - * A l - o r g a n i c m a t t e r p r o d u c t s i n p o d z o l B*
b u t d i d n o t d i s s o l v e t h e i n o r g a n i c amorphous or c r y s t a l l i n e
Fe and Al s u b s t a n c e s t e s t e d .

The o x a l a t e s o l u t i o n e x t r a c t e d

Fe a n d A l f r o m a m o r p h o u s i n o r g a n i c s u b s t a n c e s a s w e l l a s
amorphous F e - and A l - o r g a n i c m a t t e r c o m p le x e s .
d i s s o l v e c r y s t a l l i n e Fe o x i d e s .

form s.

did not

The p y r o p h o s p h a t e - d i t h i o n i t e

so lu tio n e x tracted a larg e p roportion
cry stallin e

It

o f Fe a n d A l f r o m

o x id e s as w e l l as amorphous o r g a n i c and i n o r g a n i c

He re c om me nds e i t h e r a c i d ammonium o x a l a t e

o r O.lM

p y ro p h o sp h a te as u s e f u l e x t r a c t a n t s f o r e s t i m a t i n g th e
accum ulation p ro d u c ts in p o d z o l- lik e B h o riz o n s .
Bas co mb ( 1 9 6 8 ) e x t r a c t e d F e a n d c a r b o n f r o m a n u m b e r
o f B r i t i s h s o i l s u s i n g O.lM K - p y r o p h o s p h a t e s o l u t i o n .

29
Stu d y in g th e e f f e c t
he u s e d a s e r i e s

o f pH o f s o l u t i o n on e x t r a c t i o n o f F e ,

of F e -c o n ta in in g m a te ria ls in c lu d in g a

f r e s h ly p r e c ip ita te d hydrated F e ^ H )^ ,
lep id o cro cite,

and x - r a y amorphous F e - o x i d e ,

cry stalize d g o eth ite,

a m oderately

and a t r o p i c a l l a t e r i t e .

th a t th e e x tra c tio n of c r y s ta llin e
1 0 , c o m p a r e d w i t h pH 7 .

He o b s e r v e d

o x i d e s was s l i g h t a t pH

He a l s o s u g g e s t s l i t t l e

s i l i c a t e s by py ro p h o sp h ate.

a t t a c k on

I n c o n c l u s i o n he s t a t e s

pyrophosphate e x tr a c ts p e p tiz a b le
rates

a poorly c r y s ta liz e d

th at

o rg a n ic m a t t e r and s e p a ­

a m o r p h o u s f o r m s f r o m t h e l e s s a c t i v e c r y s t a l l i n e Fe

o x i d e s b e t t e r a t a pH o f 10 t h a n a t a pH o f 7 o r 1 3 .

MATERIALS AND METHODS

S o i l s Used i n t h e S t u d y
The s o i l p r o f i l e s
two g r o u p s o f p r o f i l e s :

studied in th is

research co n sist

of

( l ) S p o d o s o l s d e v e l o p e d on a s a n d y

T o p o -b io se q u e n c e i n N o rth e rn M ich ig an and (2) w e l l - d r a i n e d
Spodosols w ith v a ry in g degree of spodic h o riz o n developm ent.
(T h e a u t h o r e x p r e s s e s h i s

a p p r e c i a t i o n t o Dr. J .

B. C o l l i n s

a n d D r . D. A. L i e t z k e f o r t h e i r p e r m i s s i o n t o u s e t h e s e s o i l
samples i n t h i s

stu d y .)

th e above p r o f i l e s ,
g illic

some o t h e r h o r i z o n s s u c h a s A ^ , K q , a r -

h o r iz o n s and f r a g i p a n s w ere a l s o i n c l u d e d i n t h e

study.
so ils

I n a d d i t i o n t o s p o d i c h o r i z o n s from

Some o f t h e p h y s i c a l a n d c h e m i c a l p r o p e r t i e s
relev an t to th is

s tu d y as w e ll as th e k in d s

of the

of h o r i ­

zons used i n t h e s tu d y a r e g iv e n i n T a b le 1, and th e a p p r o ­
xim ate lo c a t io n s

of the s i te s

leg al d escrip tio n s

a r e shown i n F i g u r e 1 .

of the lo c a tio n s

a re a ls o g iven i n T able 2.

of th e p r o f i l e s

The
studied

The f u l l p r o f i l e d e s c r i p t i o n

the s o ils

a r e g iv e n by t h e above a u th o r s

stu d ies.

However, a s h o r t d e s c r i p t i o n

of

in t h e i r re sp e c tiv e

of each p r o f i l e w i l l

be given in th e su cceed in g p a ra g ra p h s.
The f i r s t g r o u p o f p r o f i l e s w e r e s e l e c t e d f r o m a T o p o b io s e q u e n c e so t h a t i t

reflects
30

a g ra d a tio n in s o il m oisture

31
regim e and i t s
slope

r e l a t i o n s h i p w ith th e v e g e ta tio n along the

(C o llin s,

sive areas

1971).

The s o i l p a r e n t m a t e r i a l s

of sandy and g r a v e l l y t i l l s

la te p le is to c e n e age.
k e ttle holes.
of M ichigan.

and outw ash p l a i n s

Th e u p l a n d a r e a i s
V arious types

known a s a " J a c k p i n e a r e a "

o f bog and m arsh v e g e t a t i o n have

known t o b e o f t h e t y p e

The s o i l t y p e s

can

d e s c rib e d as fo llo w s:

K inross sand i s a p o o rly d ra in e d ,
(low -H um ic-G ley) w hich i s

T his s o i l has an o rg a n ic

H i s t i c H aplaquod

d e v e l o p e d f r o m medium t o v e r y

s t r o n g l y a c i d sand and g r a v e l t i l l s

th ick .

The d o m i n a n t s h r u b

of " l e a t h e r le a f " b e in g

adapted to th e p o o rly - d ra in e d a c id bog.
be b r i e f l y

of

These p l a i n s a re p i t t e d w ith g l a c i a l

developed in th e a d jo in in g k e t t l e h o le s .
cover is

are exten­

of l a t e p l e i s t o c e n e age.

s u r f a c e which i s

t h i r t e e n inches

Th e s p o d i c B h o r i z o n s c o n t a i n a g g r e g a t e s w h i c h a r e

a p p a r e n t l y h e l d t o g e t h e r by t h e r e d d is h -b ro w n h u m u s - s e s q u io x i d e s a n d some c l a y .
Low-Humic-Gley s o i l s ,

K in ro s s s e r i e s , w hich i n c l u d e s

form er

are th e p o o rly to very p o o rly d rain ed

member o f c a t e n a s w h i c h i n c l u d e s t h e w e l l d r a i n e d G r a y l i n g
or R ubicon s o i l s ,

th e m oderately w ell d ra in e d C ro sw ell,

and

t h e s o m e w h a t p o o r l y d r a i n e d AuGres s o i l s .
S a u g a t u c k - Au Gre s s a n d i s a s om ew ha t p o o r l y d r a i n e d
pedon i n t h e S a u g a tu c k s e r i e s b u t b o r d e r l i n e t o AuGres.

It

r a n g e s from A e r i e H ap laq u o d s t o E n t i c H ap laq u o d s i n c h a r a c ­
te ristic s

( G round-W ater-Podzols).

This s o i l i s d ev elo p ed in

32

T a b l e 1.

Some p h y s i c a l and c h e m i c a l p r o p e r t i e s

S o i l s e r i e s and
horizons
Kinross

S augatuckAuGres

AuGres -

Lab
No.

Bsih

1

B2 2 h l r

2

B2l"'i r
b 22-'ii
IIRpjhir’
IIBhir'm

3
4
5

of th e p r o f i l e s s tu d ied

Natu r a l
drainage

Munsell
De p t h
(inches) notation

pH

clay

sand &
gravel
drifts

poorly

11-21

5YR 3 / 3

4.5

2.1

8.2

drained

21-27

5YR 4 / 3

4.7

1.8

6.1

s and

somewhat

3- 7
7-11
I t -2 3

5YR
5YR
EYR
3’YK

4 .8
4. o
4.5

8.8
6.7
3.1

17.3
14.1
14.3

_E. 0

1.1

6.

poorly
drained

I'oihir

Croswell

CTEc
NaOAC
(pH 8 . 2 )
m . e . / l O O gm

Parent
material

s and

or.ev.r.a t
p oorly to
mode r at e y

3/3
3/3
3/4
1/27/ 3

%

■ r,

PYR 4 / I

4.7

I VI. • / 4

d .7

4 .6

EYR3 / 3 t o
7 . 5YR4/ 4
EYE 7/ 7 t o
7 . EYR4/4
;■. eyr 4 / 4
t 'V
7 . EYRE/4

^.9

K#0

4.5

‘3. l

8.6

'.2

h.L

2 . r-‘

3-1

■- 1 2

7 . r YR 4 / 4

(

2."

.1 - I d

drained
Croswell-

UPPFp j h i r

Graycal m

1 ov.’Bo-j h i r
Pgh-.ir

sand to
1h

sand v
sand
drift s

moder­
a t e l y v;ell
t o well
drained

7

Omega

P.pS

12

s a nd

well
drained

Lastport

B21

13

sand

we l 1
d ra ined

1 -;-i ■

7 . EYR 4 / 4

’L O

1-3

v;el 1
dm ined

1-9 1 / 2

10YR 2 / 1
5 YR 3 / 4 4/4
7 . 3-YR 4 / 4

4.5

4.9

11.4

3.7

1

7. 5YR 4 / 4
t, o RYR 3 / 2

5. 0

5.5
E. E

3-11

RYR 2 / 1
5 YR 5 / 1 4/1
5YR 2 / 2

4.5

16.2

11- 17

5YR 3 / 4

5.5

12. E

2 YR 2 / 3

4.5

Ru b i c o n

A1

I' 2 ] i r

14

s and

lr
!•'

ort.stein
Hi awat ha

Ai
a2

1I

13

sand

wel 1
drained

E21n i r

Onaway

Mun isi ng

0-0

!:■

E2 2 1 r

2 1

Ao
B2 i i r

22
23

E2 2 i r
E2 2 t

24

A1
a2

26

20

27

Bgjhir

28

B2 2 l r
b 3x

29
30

l oam or
sandy
1 cam
glacial
till

wel 1
drained

sandy
l oam
glacial
till

well
drained

4.5

2. E

!

2.1

7.

4.1
2.2

4.3
15 . “
5.0 13.7
7.0 24.9

17.7
4.2

7-12

RYR 3 / 4
5 YR 9 / 6

24-23

EYR 4 / 3

0-1

5YR 2 / 2

5-0

1 -c,

5YR 6 / 2

4.5

5YR 3 / 3 3/2

4 . 5 10.6
7.8
5.0

25.9
14.8

2 . 5YR 4 / 4

5.5

4.4

3-5

9-13
13- 21
21-29

3.8
.38

16 . 5

11.4
17.1
2 6 .5
7.5

T able 2.

S o i l t y p e names a n d l e g a l d e s c r i p t i o n s
s t u d i e d ( s e e a l s o F i g . 1)

of lo c a tio n s

of th e p r o f ile s

L ocation

S o il type
Omega f i n e s a n d

SW 1 / 4 o f SE 1 / 4 , S e c t i o n 2 7 , T 46 N, R 25 W.
M a r q u e tt e County

E a s t p o r t sand

SW 1 / 4 o f SW 1 / 4 o f SE 1 / 4 o f NE 1 / 4 , S e c t i o n 9 ,
t 7 N, R 17 E. S t . C l a i r C o u n t y

R ubicon sand

NE 1 / 4 o f NE 1 / 4 , S e c t i o n 1 , T 45 N, R 19 W.
A lg e r County

Hiawatha sand

NW 1 / 4 o f SE 1 / 4 , S e c t i o n 7 , T 53 N, R 35 W.
Houghton County

Onaway f i n e s a n d y lo a m

SW 1 / 4 o f SW 1 / 4 , S e c t i o n 3 3 , T 4 0 N, R 24 W.
D e l t a County

M u n i s i n g lo a m y s a n d

SW 1 / 4 o f NE 1 / 4 , S e c t i o n 4 , T 51 N, R 31 W.
B a r a g a County

K i n r o s s ,S a u g a t u c k - A u G r e s , A u G r e s - C r o s w e ll and C r o s w e l l - G r a y c a l m a r e from a
sandy to p o -b io s e q u e n c e which i s
low er p e n in su la

lo c a te d in th e N o rth ern p a r t of M ic h ig a n 's

on S t a t e F o r e s t l a n d ,

i n S o u th C e n t r a l Crowford County.

3^

me

«O TAU

_— _
P ’O D Z O L

i1 t u c e

REGjlON
_

)LCRAFT '

(SCHOOlCRAM

C h a Re C V o i I L

I*_ r’ JOTSE«01HONTMOR.

'MAI»t$TtC*t*»ORD jk-JSSAWKCti

p o d ;z o l

’ OCCANA ,*»E«ATCO

"O SC OM . * 08CMAW

! r e g ;i o n

M E C O S T A i. 1I S A B E L L A ^

I J *C»SOM

P.’O D Z O Lt I C
S T JOSEfhl bmamch

F i g u r e 1.

r WASM T E A A , t

R*
E G I O N\

' MI LL S OAL f '

Map o f M i c h i g a n s h o w i n g l o c a t i o n s
t a t i v e s o i l s used in th e study

of r e p re s e n ­

35
sandy d e p o s it s

of l a t e p l e i s t o c e n e a g e.

s t r o n g l y cem ented o r t s t e i n

This s o i l has a

in th e low er B h o riz o n w ith w e l l -

co ated sand g r a in s in th e spodic h o riz o n s .

The w a t e r t a b l e

v a r i e s d u r i n g t h e g ro w in g s e a s o n and a v e r a g e s 20" belo w t h e
surface.

S augatuck s o i l s

are im p e rfe c tly to poorly drain ed

G ro u n d -W a ter-P o d z o ls o f a c a t e n a which i n c l u d e s i m p e r f e c t l y
d r a i n e d AuGres a n d A r e n a c s o i l s w i t h o u t a c e m e n t e d B h o r i z o n ,
t h e p o o r l y d r a i n e d Roscommon s o i l s
the K inross s o i l s ) ,

(which a r e l e s s

a c id th an

t h e w e l l d r a i n e d R u b ic o n , and t h e m oder­

a t e l y w e ll d ra in e d C rosw ell s o i l s .
A uG res- C ro s w e ll san d i s an i m p e r f e c t t o m o d e r a te l y
w e l l d r a i n e d p e d o n i n t h e A u Gre s s e r i e s b u t b o r d e r l i n e t o
C rcsw ell.

The w a t e r t a b l e a v e r a g e s 3 6 " d e e p d u r i n g t h e

grow ing s e a s o n .

T his s o i l h as c h a r a c t e r i s t i c s w hich ra n g e

from E n t i c H a p laq u o d s t o E n t i c H a p l o r t h o d s and i s d e v e l o p e d
i n medium a n d c o a r s e s a n d .

It

i s a b o r d e r lin e case of

A uG re s w i t h r e s p e c t t o d r a i n a g e a n d s p o d i c h o r i z o n d e v e l o p ­
ment.
C r o s w e l l - Graycalm sand i s

a m oderately w e ll to w ell

d r a in e d pedon i n t h e C ro s w e ll s e r i e s b u t b o r d e r l i n e t o Graycalm .

It

Is c la s s if ie d

Podzol i n t e r g r a d e ) .

It

as E n tic H ap lo rth o d s
is

( G r a y Brown

d e v e lo p e d from a ra n g e of p a r e n t

m a t e r i a l e x t e n d i n g f r o m medium a n d c o a r s e s a n d s t o lo a m y
sand and san d d r i f t s w i t h t h i n t e x t u r a l bands i n t h e lo w e r
part

of the p r o f ile .

A weak f r a g i p a n o c c u r s a t t h e d e p t h

36
of 23-28".

I t s B2 h o r i z o n s h a v e c h a r a c t e r i s t i c s

developed. s p o d ic h o r i z o n .

o f a weakly-

The w a t e r t a b l e a v e r a g e s 5 8 "

d u rin g t h e grow ing s e a s o n .
The s e c o n d g ro u p o f p r o f i l e s

a r e d e v e lo p e d from sandy

t o c o a r s e loamy m a t e r i a l s w i t h w e l l - d r a i n e d m o i s t u r e r e g im e s .
Such p r o f i l e s w ere s e l e c t e d
ten sity

on t h e b a s i s

of in c re asin g i n ­

o f p e d o g e n ic p r o c e s s e s as e v i d e n t i n t h e amount o f

illu v ial
(L ietzke,

o r g a n i c c a r b o n , F e , a n d Al i n t h e s p o d i c h o r i z o n
1 9 6 9 )*

T h e r e a r e tw o g r o u p s

th e se w ell d rain ed Spodosols,

of s o i l s

included in

th o se a ls o having t e x t u r a l B

h o riz o n s and t h o s e w ith o u t t e x t u r a l B h o r i z o n s .

These s o i l s

i n c l u d e a r a n g e o f s p o d ic h o r i z o n developm ent from t h e weak­
e s t t o t h e s t r o n g e s t d e v e lo p m e n t and a r e l i s t e d i n T a b le 1,
and d e s c r i b e d b r i e f l y below .
Omega f i n e s a n d i s

a w e l l d r a i n e d T y p ic Udipsamment

(Brown P o d z o l i c s o i l ) w h i c h h a s d e v e l o p e d f r o m s a n d i n a n
outwash p l a i n .

The v e g e t a t i o n i s

r e i n d e e r m oss, and b l u e b e r r i e s .

jack pine,

sweet f e r n ,

Some o f t h e Omega s e r i e s

is

f o u n d t o h a v e i n t e r m i t t e n t t h i n g r a y A2 a n d d a r k r e d d i s h b r o w n B^ h o r i z o n s s u g g e s t i n g a w e ak p o d z o l p r o f i l e .

However,

th e y g e n e r a l l y la c k ev id en ce of spodic h o riz o n developm ent.
Omega i s

a w e l l d r a i n e d member o f a c a t e n a w h i c h i n c l u d e s

t h e s o m e w h a t p o o r l y d r a i n e d Au Gre s a n d t h e p o o r l y d r a i n e d
Roscommon s e r i e s .

37
E a s tp o rt sand i s

a w e l l d r a i n e d S p o d ic Udipsamment

( R e g o s o l - P o d z o l i n t e r g r a d e ) w h i c h h a s d e v e l o p e d f r o m s a n d on
la k e benches and b e ac h r i d g e s .

The v e g e t a t i o n i s

a sp e n and

choke c h e r r y , w i t h g ro u n d c o v e r o f weeds and g r a s s e s .
pedons of t h i s

series

A few

a r e known t o h a v e w e a k l y c e m e n t e d t h i n

chunks of o r t s t e i n i n t h e low er p a r t of t h e B h o r i z o n .
w ell d rain ed E a s tp o rt,

The

a l o n g w i t h t h e so m e w h a t p o o r l y

d r a i n e d Roscommon, f o r m a d r a i n a g e s e q u e n c e o r c a t e n a .
R ubicon sand i s

a w ell d ra in e d E n tic H aplorthod

(w eakly d e v e lo p e d P o d z o l) w hich h a s d e v e lo p e d from sandy
p a r e n t m a t e r i a l on o u t w a s h p l a i n s ,
The v e g e t a t i o n a s s o c i a t e d w i t h t h i s
pine,

till

p lain s

or m oraines.

so il consists

of red

o a k , a few a s p e n , a n d g r o u n d c o v e r o f p r i m a r i l y b r a c k e n

fern.

Th e s p o d i c h o r i z o n s c a n b e r e c o g n i z e d i r . t h e f i e l d ,

a n d i n some p e d o n s a f e w w e a k l y c e m e n t e d c h u n k s may b e p r e ­
sent in th e B ^ i r horizon.

It

i s t h e w e l l d r a i n e d member

of a d rain ag e sequence th a t in c lu d e s th e m oderately w ell
d ra in e d C rosw ell s e r i e s ,
series,

t h e so m e w h a t p o o r l y d r a i n e d Au Gre s

a n d t h e p o o r l y d r a i n e d Roscommon o r K i n r o s s s e r i e s .
H iawatha san d i s

a w e ll d r a i n e d Typic H a p lo rth o d

( w e l l - d e v e l o p e d P o d z o l) d e v e lo p e d i n sand of outw ash p l a i n s
or g l a c i a l t i l l .

The v e g e t a t i v e c o v e r a t t h i s

site

co n sists

o f c u t - o v e r h a rd m aple f o r e s t w ith a quack g r a s s and tim o th y
sod.

H iawatha s o i l s have s t r o n g and d i s t i n c t

developm ent.

spodic h o rizo n

I n some p e d o n s t h e B g q h i r a n d B2 2 i r h o r i z o n s

38
are s lig h tly

to s tro n g ly coherent in p la c e s , w ith f a i r l y

th ic k pieces

o f cem ented o r t s t e i n w hich c r u s h u n d e r m o d erate

pressure.

H iaw atha i s

t h e w e l l d r a i n e d member o f t h e d r a i n ­

age seq u e n c e w hich i n c l u d e s t h e i m p e r f e c t l y d r a i n e d W a te rs meet ( t e n t a t i v e s e r i e s ) ,
cem ented B ) ,

S au g a tu ck (Ground-W ater P odzol w ith

a n d t h e p o o r l y d r a i n e d Roscommon o r K i n r o s s

so ils.
Onaway f i n e s a n d y lo a m i s

a w ell d ra in e d A lfic H aplor­

t h o d ( m i n i m a l P o d z o l g r a d i n g t o G r a y Brow n P o d z o l i c )
on c a l c a r e o u s lo a m o r s a n d y l o a m g l a c i a l t i l l
o r on m o r a i n e s .
birch,

and a s p e n .

Onaway s o i l s h a v e a f i n e

lo a m u p p e r s e q u e n c e o f h o r i z o n s

horizons

in t i l l

plains

The v e g e t a t i o n i s m a i n l y r e d m a p l e , w h i t e

balsam f i r

Ag h o r i z o n s ,

developed

sandy

o f b l a c k Op h o r i z o n , b r o w n

and a d a rk r e d d is h -b ro w n and r e d d is h -b ro w n B p ir

of s lig h t

o rg a n ic m a t t e r and i r o n a c c u m u la tio n s ,

and a lo w e r s e q u e n c e o f h o r i z o n s o f l i g h t r e d d i s h - b r o w n and
I
!
d a r k r e d d i s h - b r o w n lo a m Ap a n d B g p t h o r i z o n s , a n d a l i g h t
brown and brown C h o r i z o n s
so il is

o f loamy c a l c a r e o u s t i l l .

Onaway

a w e l l d r a i n e d member o f t h e d r a i n a g e s e q u e n c e w h i c h

i n c l u d e s somewhat p o o r l y d r a i n e d M ackinac and t h e p o o r l y
d ra in e d A ngelica s o i l s .
M u n is in g loamy s a n d i s

a w ell drained A lfic F rag io rth o d

( P o d z o l g r a d i n g t o G r a y Brow n P o d z o l i c s o i l w i t h f r a g i p a n ) .
This s o i l i s
rain ic

area

d e v e l o p e d i n s a n d y lo a m g l a c i a l t i l l
of W isconsin age.

i n a mo-

Hard m a p le and y e llo w b i r c h

39
a r e th e dom inant v e g e t a t i o n i n t h i s
so ils

are b i-se q u a l s o ils .

lo catio n .

The M u n i s i n g

T y p i c a l l y t h e y h a v e an u p p e r

sequum c o m p r i s e d o f t h i n , b l a c k ,

f i n e s a n d y lo a m A-^ h o r i z o n ,

a p i n k i s h g r a y l o a m y s a n d A2 h o r i z o n ,

and d a rk re d d is h -b ro w n

and r e d d i s h - b r o w n san d y loam B i r h o r i z o n s .

The l o w e r seq uu m

i s c o m p ris e d o f a v e r y com pact f r a g i p a n o f g r a y loamy san d
'
i
■^2x h o r i z o n , r e d d i s h - b r o w n s a n d y l o a m E ^ i t x h o r i z o n , r e d d i s h t
b r o w n s a n d y lo a m B2 p t h o r i z o n , a n d r e d d i s h - b r o w n s a n d y lo a m
C horizon.

M unising i s

seq u en ce which i n c l u d e s

a w e l l d r a i n e d member o f a d r a i n a g e
s om ew ha t p o o r l y d r a i n e d S k a n e e s o i l s

a n d p o o r l y d r a i n e d Gay s o i l s .
M ethods Used i n t h i s S tu d y
M ethods u s e d i n t h i s
(l)

study c o n s is t

o f two p a r t s :

t h e e x t r a c t i o n p r o c e d u r e s and ( 2 ) t h e q u a n t i t a t i v e d e t e r ­

m in atio n of the i l l u v i a l

o r g a n i c c a r b o n , Fe a n d A1 i n t h e

so il ex tracts.
The a q u e o u s e x t r a c t a n t s u s e d i n t h e s t u d y a r e o f t h e
ty p e which have t h e a b i l i t y

to c h e la te m etals.

tin g agents in c lu d e th e te tra -so d iu m s a l t
acid

( N a^-pyrophosphate),

Such c h e l a ­

of pyrophosphoric

an i n o r g a n i c c h e l a t i n g a g e n t ,

w e l l a s t h e f o l l o w i n g Na s a l t s

of organic c h e la tin g ag en ts:

d i e t h y le n e t r i a m i n e p e n t a a c e t ic a c id , pentasodium s a l t
DPTA); e t h y l e n e d i a m i n e t e t r a a c e t i c
EDTA); a n d n i t r i l o t r i a c e t i c

as

acid,

(Na^-

disodium s a l t

a c id disodium s a l t

(Na2 -

(Na2 -NTA).

4o
The c h e m i c a l f o r m u l a e a n d t h e s t a b i l i t y

constants

of th e se

c h e l a t i n g a g e n t s w i t h F e a n d A1 a r e p r e s e n t e d i n T a b l e 3 .
E xtracting procedure:
u sed, as fo llo w s:

2g.

B asco m b 's

air-d ry so il

250ml. c e n t r i f u g e b o t t l e s

( 1 9 6 8 ) p r o c e d u r e was

( < ^ 2mm) w e r e p l a c e d i n

( p o l y p r o p y l e n e ) a n d 2 0 0 m l o f 0.1M

e x t r a c t i n g s o l u t i o n were added t o t h e s o i l s .
containing s o ils

and s o l u t i o n s w ere capped and s h a k e n o v e r ­

n i g h t a t room t e m p e r a t u r e .
w ere added and t h e b o t t l e s
A fter th is

of 0 .4 $ s u p e r flo e

shaken a g a in f o r f i v e m in u te s.

o r u n t i l t h e s u p e r n a t a n t l i q u i d was c l e a r i n r e ­

flected lig h t.

The s o i l e x t r a c t s w e r e t h e n t r a n s f e r r e d t o

containers

for fu rth er an aly sis.

S o il ex tract c o lo r:
100ml g l a s s b o t t l e s ,
uniform .

Five drops

t h e s a m p l e s w e r e c e n t r i f u g e d a t 2 , 0 0 0 rpm f o r

te n m inutes

p lastic

The b o t t l e s

The s o i l e x t r a c t s w e r e p l a c e d i n

th u s keeping th e s o lu ti o n th ic k n e s s

Th e c o l o r v a l u e s w e r e d e t e r m i n e d i n r e f l e c t e d

l i g h t by me an s o f a M u n s e l l c o l o r c h a r t .
S o il e x tra ct re a c tio n :

The h y d r o g e n i o n a c t i v i t y

of

th e e x t r a c t i n g s o l u t i o n s were d e te r m in e d b e f o r e e x t r a c t i o n
and im m e d ia te ly a f t e r e x t r a c t i o n .

A glass

Z e r o m a t i c pH m e t e r was u s e d i n t h e s o i l

e l e c t r o d e Bec km an

ex tra ct reactio n

m easurem ent.
Fe and Al i n t h e s o i l e x t r a c t s :

The e x t r a c t s w e r e

a n a l y z e d f o r i r o n a n d a l u m i n u m u s i n g a 303 m o d e l P e r k i n - E l m e r
atom ic a b s o r p t i o n s p e c t r o - p h o t o m e t e r .

A c e ty le n e and a i r were

41

Table 3.

Chemical formulae and some of the equilibrium constants of the
chelating agents used in this study

Ligand

Abbreviated formula

Metal ion
Equilibrium constants
_____________________ Log (K)_________

Pyrophosphoric acid
Fe (II)

0 = P^_OH

(Na^PpOy)

Fe (III)

0 = P < — -OH

^"-OH

A1 (III)

Diethylenetriaminepentaacetic acid
DPTA

HOOCCH,H—

,

CHpCOO

CH2

?h2
-Ni

Fe (II)

16.5

Fe (III)

2 8 .6

(Na5DPTA)

CHgCOO
A1

CH2

(III)

CHo
H—
OOCCH.

-CH2COOH

Ethylene diaminetetraacetic acid,
EDTA

OOCCHp

/c h 2 c o o

Fe (II)

14.33

Fe (III)

25.1

A1 (III)

16.3

(Na2H2 EDTA)
H — iriCH2C H 2Ni

HOOCCH, /

c h 2c o o h

Nitrilotriacetic acid,
NTA

Fe

(II)

8 .8 2

,c h 2c o o
Fe (III)
HN-

•c h 2c o o h

(Na2HNTA)
A1

'CH2C00H

(III)

15-9

42
used f o r i r o n d e t e r m i n a t i o n as f u e l and o x id a n t,
ively.
oxide

resp ect­

The o x i d a n t u s e d f o r A1 d e t e r m i n a t i o n was n i t r o u s
to provide a

h o t t e r flam e.

th e e x t r a c t were c a l c u l a t e d u s i n g
CV ( d f )
% e l e m e n t =vyVj_Q ~$qq
' '
5

The p e r c e n t Fe a n d A1 i n
the follow ing equation:

W h er e

V = volume i n u n d i l u t e d sample
d .f. = d ilu tio n facto r
W = w eight of
sample
C = concentration
of elem ent in
sample s o l u ­
tio n s obtained
from s t a n d a r d
c u r v e i n ppm

The e l e m e n t a l F e a n d A1 a r e e x p r e s s e d i n p e r c e n t a g e
o f t h e s o i l sam p le, oven d r y .
T o tal carbon in s o i l s b e fo re e x t r a c t i o n :

T otal c a r­

bon i n s o i l s w ere d e te r m in e d by t h e d r y c o m b u stio n method
u s i n g a "LECO 70 S e c o n d C a r b o n A n a l y z e r " .

S o i l sam ples were

ground f o r s i x m in u tes i n a h ig h speed im pact s h a k e r,
one h u n d r e d m i l l i g r a m s

of f i n e l y ground s o i l

then

( 8 0 m e s h ) was

p l a c e d i n t o a s p e c i a l c e r a m i c c r u c i b l e a n d one s c o o p ( a p p r o x ­
i m a t e l y 1 gram) e a c h o f i r o n c h i p and t i n
added.

a c c e l e r a t o r s were

The c r u c i b l e was p l a c e d i n t h e s p a c e p r o v i d e d i n t h e

c o m b u s t i o n t u b e o f t h e i n d u c t i o n f u r n a c e t h r o u g h w h i c h 02
was b e i n g p a s s e d .
over l670°C ,
read ily .

The c o m b u s t i o n t u b e p r o v i d e s a t e m p e r a t u r e

s u f f i c i e n t l y high t o

o x i d i z e or b u rn t h e sample

Th e C i n t h e s a m p l e was o x i d i z e d t o C02 .

Th e g a s

m i x t u r e l e a v i n g t h e i n d u c t i o n f u r n a c e was p a s s e d t h r o u g h a

43
dust trap to f i l t e r

out th e s o l i d t i n and i r o n o x id e s ,

f o l l o w e d b y a s u l f u r t r a p c o n t a i n i n g Mn02 t o a b s o r b s u l f u r
g a se s which m ig h t have b e en o x id iz e d d u r in g t h e c o m b u stio n
of th e sam ple, and f i n a l l y th ro u g h a h e a te d c a t a l y s t t o
d i z e a n y CO f o r m e d t o C02 .
was r e m o v e d b e f o r e i t

o xi­

The m o i s t u r e o f t h e g a s m i x t u r e

e n t e r e d t h e a n a l y z e r by an an h y d ro n e

trap .
Th e g a s m i x t u r e ( 0 ^ a n d C02 ) w h i c h h a d u n d e r g o n e t h e
c o m b u s t i o n a n d p u r i f i c a t i o n p r o c e s s e s was t h e n p a s s e d i n t o
a c y l i n d e r l o c a t e d i n a t e m p e r a t u r e - c o n t r o l l e d oven (450°C)
in the analyzer.

The t h e r m a l c o n d u c t i v i t y o f t h e g a s m i x t u r e

i n t h e c y l i n d e r was m e a s u r e d b y m e an s o f a t h e r m a l c o n d u c ­
tiv ity cell

of a t h e r m i s t o r - t y p e .

The o u t p u t o f t h e t h e r m a l

c o n d u c t i v i t y c e l l was r e a d on a s p e c i a l DC d i g i t a l v o l t m e t e r
as p e r c e n t carb o n ($C).
T o tal carbon in s o i l s
sam ples

a fte r ex tractio n :

( a f t e r b e i n g s u b j e c t e d t o e x t r a c t i o n ) were washed

w ith d i s t i l l e d w a te r i n #42 f i l t e r p a p e r s

on g l a s s f u n n e l s .

The w a s h i n g s w e r e r e p e a t e d u n t i l t h e f i l t r a t e
n e u t r a l pH.
used.

The s o i l

S i x t o n i n e h u n d re d m l.

resum ed a

o f d i s t i l l e d w a t e r was

Th e s a m p l e s w e r e t h e n a i r - d r i e d a n d t h e i r t o t a l c a r ­

bons were d e t e r m i n e d by t h e d r y c o m b u s tio n p r o c e d u r e a l r e a d y
d escribed.

RESULTS AND DISCUSSION

P relim inary S tudies
P relim inary stu d ie s
a f f e c t in g the e x tr a c tio n
The d i s c u s s i o n

concerning th e v a rio u s f a c to r s

of Fe, A l,

of the r e s u l t s

and c a rb o n w ere c o n d u c te d .

of such ex p erim en ts fo llo w s:

E f f e c t of c o n c e n t r a t i o n of t h e e x t r a c t a n t :
o f 0 .1 M , 0.2 M ,

S o lu tio n s

a n d O . 5M Nag-NTA a n d a l s o 0.1M a n d 0.2M

Na2 ~EDTA w e r e a p p l i e d t o s o i l s a m p l e s .

The e x t r a c t i o n p r o ­

c e d u r e o f Bascomb was f o l l o w e d a n d s l i g h t l y m o d i f i e d b y
using d if f e r e n t c o n ce n tra tio n s
The r e s u l t s

of th e re a g e n ts as in d ic a te d .

a r e shown i n T a b l e 4 .

The s e l e c t e d s p o d i c h o r i ­

z o n s a s w e l l a s o r t s t e i n a n d f r a g i p a n s a m p l e s do n o t s eem t o
have r e l e a s e d h i g h e r amounts o f s e s q u i o x i d e w i t h i n c r e a s i n g
c o n c e n tra tio n of the re a g e n t.
However, t h e a r g i l l i c h o r i z o n
I
( ^ 2 2 ^ ) o f t h e Onaway s e r i e s a n d t h e H i a w a t h a B2 ^ h i r s ho w e d
p r o g r e s s i v e l y low er v a lu e s

o f e x t r a c t a b l e Fe w i t h i n c r e a s i n g

r e a g e n t c o n c e n t r a t i o n , w h ile e x t r a c t a b l e Al i n c r e a s e d
slig h tly .
Effect

of e x t r a c t i o n tim e and s h a k in g t r e a t m e n t s :

Some s e l e c t e d s p o d i c h o r i z o n s a m p l e s w e r e s u b j e c t e d t o 0.1M
s o l u t i o n o f Nap-NTA a n d Nap-EDTA f o r t h r e e d i f f e r e n t
44

T able 4.

E f f e c ts of c o n c e n tra tio n of e x t r a c t a n t s
Al from s o i l s

E xtractants

N a 2 -NTA

H orizon

0 .1M

on t h e e x t r a c t i o n o f Fe a n d

“0.2M

and

675M

concentration

N a2 -EDTA

O I

0.2M

Fe%

A lfa

Fe$

Al %

Fefo

A l fo

Fe%

A l fo

Fefo

Al %

.08

.04
.18

.10

trace

trace

.10

.49

.19

• 03
• 54

.13

.33

.03
.10

.15
.38

.11
.05
.10

.20
.14

.12
• 05
.10

.19
.10

AuG res-Crosw ell
C rosw ell-G raycalm

B2 j h i r
B2 i h i r

.29
.16

R ubicon

B2 1 i r

R ubicon

• 51

.26
.18

• 37
.20

.27
.18

• 29
.2 1

.21

.19

.11

• 45
.21

.2 1

o rtstein

.23
.11

.33
.23
.41

.10

.39
.20

.05

.11 t r a c e

.10

H iaw atha

B2 1 h i r

• 56

.25

.48

.42

.28

• 51

.21

.45

.28

Onaway

B2 2 t

.40

.12

• 38

.14

MO
CM
•

trace
.20

CM
•

B2 1 h i r
B2 1 h i r

mo

K inross
S augatuck-A uG res

.16

. 06

.12

.10

M unising

B2 ^ h i r

.48

.47

.46

.44

M unising

b 3x

.07

.49
.09

.15
.44

.50
.04

• 53
.51
.06 t r a c e

.28

.21

.17

• 19

mean
standard e rro r

.25
-.009

.07 t r a c e
.26
.23
-.008

.09

.03
.26

.20

.15

.18

.59
.06
.21

46
e x tra c tio n tim es.

The f i r s t g r o u p was s h a k e n c o n t i n u o u s l y

f o r a p e r i o d o f f o u r t e e n h o u r s b y me an s o f a m e c h a n i c a l
shaker.

The s e c o n d g r o u p was s h a k e n o c c a s i o n a l l y b y h a n d

f o r t h e same p e r i o d o f t i m e .
hand o c c a s i o n a ll y

Th e t h i r d g r o u p was s h a k e n b y

f o r a p e r i o d of f i v e days (120 h r s . ) .

Nai4.- P 2 ° 7 was a l s o u s e d a s a n e x t r a c t a n t i n t h e f i r s t
The m i x t u r e s

group.

of s o i l and s o l u t i o n s w ere c e n t r i f u g e d a f t e r

each s p e c i f i e d e x t r a c t i o n p e r i o d and t h e c l e a r e x t r a c t s were
a n a l y z e d f o r Fe a n d A l .

The r e s u l t s

of t h i s

experim ent a re

shown i n T a b l e 5*
The d a t a r e v e a l s t h a t i n g e n e r a l t h e f o u r t e e n h o u r s
of o ccasio n al shaking tre a tm e n t b j

r e s u l t e d i n low er y i e l d s

o f b o t h e x t r a c t a b l e Fe a n d A l f r o m t h e s e s o i l s a m p l e s .
t r a c t i o n t i m e o f 120 h o u r s ,
ex tractio n
tinuous

treatm ent c,

o f Fe a n d A l , a n d f i n a l l y

shaking tim e,

treatm ent a,

a m o u n t s o f e x t r a c t a b l e Fe a n d A l .

caused th e g r e a te s t

th e fo u rte e n hours con­

released interm ediate
The e f f e c t s

of c o n t a c t betw een s o i l and e x t r a c t a n t ,
d uration,

Ex ­

of th e tim e

as w e ll as sh a k in g

a r e m o s t d i v e r s e i n t h e a m o u n t s o f Fe a n d A l e x ­

t r a c t e d from t h e b e t t e r d r a i n e d s o i l s w i t h s t r o n g e r s p o d i c
h o riz o n developm ent.

F urtherm ore,

th ese r e s u lts

suggest

t h a t a l t h o u g h b o t h Na2 -NTA a n d Na2 -EDTA h a v e e x t r a c t e d m o re
Fe a n d Al a f t e r 120 h o u r s e x t r a c t i o n t i m e ,
c r e a s e o f Fe e x t r a c t i o n i s
A l.

the r a te

of i n ­

s u b s t a n t i a l l y h ig h e r th a n t h a t of

T able 5 .

E f f e c t o f s h a k i n g a n d e x t r a c t i o n t i m e on t h e a m ou nt o f Fe a n d A l e x t r a c t e d
b y t h r e e 0.1M c h e l a t i n g a g e n t s
E x t r a c t a n t s ,, e x t r a c t i o n t i m e s a n d s h a k i n g t r e a t m e n t s
IM3 2 -W'-L'/V
iNa2
Na4P2®7
(c )
14 h r ^ a ) 14 h r ( a ) 14 h r ^ 12 0 h r
1 14 h r l' a ; 14 h r 1, D^ 12 0 h r l' C ^

C helating agent
E x t r a c tio n tim e

Fe#

A l#

Fe#

H orizon Fe# A l#

K inross

E'2 2 h i r

tr.

. 06

tr.

.08

tr.

S augatuck-AuGres

B2 1 h i r

. 1 9 • 39

.20

.51

.24

A uG res-Crosw e!1

B 2ihir

.24 .29

. 2 9 .3 3

.31

C r o s w e l l - G r a y c a l m B2 ]_hir

.1 2

.18

.16

.23

.20 .21

• 29 . 3 0

Rubicon

B2 1 i r

• 15 . 2 4

.23

.4 1

. 1 5 • 36

.48

Hiawatha

B 2ihir

• 51 . 2 6

.56

.25

Onaway

B2 i i r

. 4 0 • 30

.4 3

M unising

B pphir

.4 7
.2 6

mean
standard e rro r

A l# Fe#

Al# Fe#

S o il S eries

A l#

A l#

Fe# Al#

.0 8 .12

tr.

.09

tr.

.05

. 0 7 . 16

.36

.58

.1 3

• 33

.10

• 25

• 19 • 39

.38

• 39

.1 1

.20

.14 .20

• 29 . 2 1

.05 .14

tr.

.10

.15

.20

• 50

.10

.20

.05 .18

.21

.28

. 4 7 • 15

. 8 5 • 29

.51

.2 1

• 32 . 1 7

.66

.31

.28

. 3 8 .2 1

• 91 • 35

.22 .21

.17

.30

.24

.60

. 4 8 .4 7

.40 .38

.75

.62

.50

•53

• 31 . 4 2

. 6 7 .5 6

.29

• 29 .3 2

.26

.51

• 39

.20 .24

.1 4 .19

.32

.08

.29

.27

+ .0 3 ± . 0 1

( a ) O v e r n i g h t , 14 h o u r s , s h a k i n g i n a r e c i p r o c a l s h a k e r
( b ) O c c a s i o n a l s h a k i n g o v e r n i g h t , , 14 h o u r s
( c ) O c c a s i o n a l s h a k i n g f o r a p e r i o d o f 5 d a y s , 120 h o u r s

.17

.29

The Na^-DPTA s o l u
tio n at i t s

n a t u r a l pH o f 12* a s w e l l a s a t p H ' s o f 7 a n d

10. were a p p l i e d t o s o i l s .

(HC1 was u s e d t o a d j u s t t h e pH

t o 7 and 1 0 .)

The a m o u n t s o f F e a n d A l w e r e d e t e r m i n e d i n

the e x tr a c ts .

C a r b o n was d e t e r m i n e d i n t h e s o i l b e f o r e a n d

a f t e r e x t r a c t i o n a n d t h e d i f f e r e n c e was r e c o r d e d a s t h e
d is p e rs e d organic carbon.
The d a t a r e v e a l s

The r e s u l t s

a re giv en in T able 6 .

a g e n e r a l t r e n d o f i n c r e a s i n g amount

of e x t r a c t a b l e F e , Al and o r g a n i c c a r b o n w i t h i n c r e a s e
pH o f t h e e x t r a c t a n t .

However,

of the

t h e n a t u r a l pH o f 12 o f

Na^-DPTA a p p e a r e d t o b e t o o h i g h t o d e t e c t a n y Fe i n
so lu tio n .
These r e s u l t s

a r e in agreem ent w ith th e stu d y of

T i n s l e y a n d S a l a m ( 1 9 6 1 ) i n w h i c h t h e y s u g g e s t t h a t a s pH
is

r a i s e d th e e q u ilib r iu m betw een
F e r r ic hydroxide
p recip itate
Fe

7 /

io n c o n c e n tra tio n

M etal-o rg an ic com plex^^
Al

A lum inate in
so lu tio n
is

lik ely

t o be d i s p l a c e d t o th e r i g h t w ith c o n se q u e n t i n ­

crease in s o l u b i l i t y
The r e s u l t s

o f t h e o r g a n i c complex.

o b ta i n e d from t h e p r e l i m i n a r y s t u d i e s

make o b v i o u s t h e n e e d f o r some s t a n d a r d p r o c e d u r e a s t o t h e
e f f e c t of e x tr a c tio n tim e,

reagent c o n cen tratio n ,

a n d pH.

Ev en t h o u g h t h e l o n g e r t i m e o f c o n t a c t b e t w e e n r e a g e n t a n d

Table 6.

The e f f e c t o f t h e pH o f 0.1M Na^-DPTA s o l u t i o n s

on t h e e x t r a c t a b i l i t y

of

F e, Al and o rg a n ic c a rb o n o f s o i l sam ples

Na5 --DPTA

CD

hi

pH = 10

11

pH = 7

H orizon

%

S o il series

k lfo

K inross

B2 2 M r

tr.

.08

.08

tr.

. 06

-

tr.

.04

.12

Saugatuck-A uG res

B 2ihir

.1 2

.30

•89

.15

.41

•97

tr.

.53

1.49

AuG res-Crosw ell

B2 ^ h i r

.09

.19

• 32

.21

• 30

.44

tr.

.34

.50

Crosw ell-G raycalm

B2 1 h i r

.04

.1 2

.10

.10

.19

-

tr.

.26

-

R ubicon

B2 1 i r

.09

.21

.10

.18

.27

.20

tr.

.44

.25

Hiawatha

B2 ]_hir

.49

. 16

.51

.58

.20

.68

tr.

.22

.97

Onaway

B2 i i r

.20

.20

.37

.33

.47

.48

tr.

.41

.42

M unising

B2 1 h i r

A l

A l

1.10

.40

.56

1 .90

tr.

A l

2.13

.19

.2 2

.43

.24

• 31

.58

.34

.74

me ans
s t a n d a r d e r r o r f o r pH c l a s s

C

fo*

F efo

k lfo

Cfo

Fefo

k lfo

C.%

-. 07

*Th e p e r c e n t a g e s o f e x t r a c t e d c a r b o n i s b a s e d on t h e t o t a l d r y c o m b u s t i o n v a l u e s o f
o r i g i n a l s o i l and a f t e r e x t r a c t i o n .
Dashes i n d i c a t e n e g a t i v e carb o n v a l u e s .

s o i l m a t e r i a l a p p e a r e d t o r e s u l t i n h i g h e r amounts of e x t r a c t a h l e Fe a n d A l , t h e f o u r t e e n h o u r s

of continuous

s h a k i n g f o r p r a c t i c a l p u r p o s e s i s m o re s u i t a b l e .

The r e ­

a g e n t c o n c e n t r a t i o n o f 0 . 1M a l s o p r o v e d t o b e m o r e e f f i ­
c ie n t sin ce the s e n s i t i v i t y

of th e atom ic a b s o r p tio n u n i t

drops w ith i n c r e a s i n g c o n c e n tr a tio n of th e r e a g e n t.
t h e pH h a s a p r o n o u n c e d i n f l u e n c e
illu v ia l m aterials,
However, i t

as i s

F in ally ,

on t h e e x t r a c t a b i l i t y

of

e v i d e n t f r o m t h e s t u d y w i t h DPTA.

seemed d e s i r a b l e t o u s e t h e r e a g e n t s a t t h e

n a t u r a l pH o f t h e i r s o l u t i o n s a n d t o s t u d y t h e e f f e c t
range of pH 's as w e l l as t h e e x t r a c t a n t s

of a

them selves.

C o n s i d e r i n g t h e above p r e l i m i n a r y s t u d i e s , B asco m b 's
( 1 5 6 8 ) p r o c e d u r e was a d a p t e d a n d s l i g h t l y m o d i f i e d b y s u b s ­
titu tin g

d ifferen t

organic c h e la tin g agents w ith d i f f e r e n t

pH 's f o r t h e K -p y ro p h o s p h a te .

A lso,

s o d i u m was u s e d a s a n

accompanying c a t i o n w ith a l l t h e e x t r a c t i n g r e a g e n t s .
d iscussion

of th e r e s u l t s

The

follow s.

P rin c ip a l S tudies
pH o f t h e e x t r a c t i n g
t a c t w ith th e s o i l
in th is
4 .6 ,

sam ples:

s o l u t i o n s b e f o r e and a f t e r c o n ­
The e x t r a c t i n g s o l u t i o n s u s e d

tudy p ro v id e a range of p H 's.

T h e s e a r e pH 3 - 2 ,

1 0 , a n d 1 2 , c o r r e s p o n d i n g t o 0.1M s o l u t i o n s

Nag-EDTA, N a ^ - p y r o p h o s p h a t e ,

o f Nag-NTA,

a n d Na^-DPTA, r e s p e c t i v e l y .

The Na^DPTA s o l u t i o n was b u f f e r e d s t r o n g l y e n o u g h t o m a i n ­
t a i n a c o n s t a n t pH e v e n a f t e r b e i n g i n c o n t a c t w i t h t h e s o i l

51
sam ples s t u d i e d ,

Table 7.

The N a - p y r o p h o s p h a t e s o l u t i o n s

m a i n t a i n e d t h e i r i n i t i a l pH v a l u e s w i t h i n 0 . 3 pH u n i t .
ever,

the

How­

h o r i z o n of th e H iaw atha and M unising s e r i e s

l o w e r e d t h e pH o f t h e N a ^ - p y r o p h o s p h a t e e x t r a c t i n g s o l u t i o n s
0 . 5 and 0 . 7 u n i t s ,

resp ectiv ely .

c h a n g e t h e pH o f t h e

Those h o r iz o n s d i d n o t

other e x tra c tin g s o lu tio n s ap p re cia b ly .

The p H ' s o f t h e Na2 ~HTA a n d Nag-EDTA e x t r a c t a n t s u s u a l l y r e ­
m a i n e d w i t h i n 0 . 1 pH o f t h e i r o r i g i n a l r e a c t i o n s .
Nag-NTA pH was r a i s e d

from

3 . 2 t o 3 . 6 a n d t h e Na2 ~EDTA pH

was r a i s e d f r o m 4 . 6 t o 4 . 7
h o r i z o n o f t h e Onaway
The r i s e

The

a f t e r c o n ta c t w ith th e a r g i l l i c

so il series.

i n pH o f e x t r a c t i n g s o l u t i o n s (N a2 -NTA a n d

Na2 -EDTA) u p o n c o n t a c t w i t h t h e a r g i l l i c

h o rizo n of th e

Onaway s o i l s e r i e s may b e a t t r i b u t e d t o a t t a c k
m i n e r a l s by s o l u t i o n s

on s i l i c a t e

o f su ch low p H 's and c o n s e q u e n t r e l e a s e

of hydroxyl io n s to th e environm ent.
C olor o f th e s o i l e x t r a c t s :
for e x tra c t colors

The M u n s e l l n o t a t i o n s

a r e shown i n T a b l e 8 .

The A-j_ h o r i z o n

e x t r a c t s were c o n s i d e r a b l y l i g h t e r i n c o l o r as compared t o
th e spodic h o riz o n e x t r a c t s .
w e r e m o re y e l l o w i s h i n c o l o r

H o w e v e r , t h e Na^-NTA e x t r a c t s
( w i t h h u e s o f 2 . 5 7 a n d 57 )

w h i l e t h e Na^-EDTA, N a ^ - p y r o p h o s p h a t e ,
colors

a n d Na^-DPTA e x t r a c t

r a n g e d from t h e y e l l o w i s h brown t o d a r k brow n.

poorly drained s o ils

(K in r o s s and S a u g a tu c k ) had c o l o r s

m o stly in brow nish y ello w

(107R 6/ 6 ) w i t h Na2 -NTA a n d

The

T able 7.

pH v a l u e s o f t h e e x t r a c t i n g s o l u t i o n s b e f o r e a n d
a f t e r c o n ta c t w ith s o i l sam ples

S o il se ries

H orizon

E x t r a c t a n t ( i n i t i a l pH)
Na2 NTA
Nag'EDTA
Na^P^O^
( PH = 3 » 2 )

K inross

( pH =4 . 6 )

(pH =10)

B2 1 ^
B2 2 h i r

3.2

4 .4

9 .8

3-2

4 .4

9 .9

B2 i h i r

3-3

4.6

10.1

B2 2 h i r

3.3

4 .5

IIB 2 ]_hir'
I I B h i r ’m

3.3
3.2

4 .5

9 .9
1 0 .0
1 0 .0

B2 ]_ hir
B2 2 h i r

3.2
3.3

4 .6
4 .6

10.2
10.3

3 .3
3.2

4 .6
4 .5

10.2
10.2

B2 2 h i r

3.1

4 .5

10.3

Omega

b22

4.6

10.3

E astport

b21

3.3
3.2

10.3

Rubicon

A1
B 21ir
B 22ir
o rtstein

3.2

4 .5
4 .4

3-3

4 .6

3.1
3.2
3.2

4 .6

3.3
3.2

4 .5
4.6

3.3
3.2

4 .5

9-9
10.2

4 .5

9 .8

3.3
3.3
3.6

4 .5
4 .4
4 .7
4 .4
4 .4
4.6
4 .6

10.0
10.1
10.1

Saugatuck-A uG res

A uG res-C rosw ell

C ro sw e ll-G ray c a lm U PP.Bp^hir
l o w B2 j h i r

H iaw atha

Al
a2
B2 ]_hir
B22 l r

Onaway

M unising

a2
B22lr
B2 2 i r
B2 2 t
A1
A2
B2 l h i r
B2 2 i r

3.2
3.2
3 .3
3.3

4 .5
4 .4

9.7
10.1
10.2
10.2
9-5
1 0 .0

9.3
9 .9
9-9
10.1

53
Na^-EDTA, w h i l e y e l l o w c o l o r s w e r e d o m i n a n t w i t h N a ^ - p y r o p h o s p h a t e a n d Na^-DPTA.
spodic h o riz o n s

The c o l o r o f t h e h i g h l y d e v e l o p e d

(H iaw atha and M u n isin g )

ra n g e d from s t r o n g

b ro w n ( 7 - 5 YR 5 / 6 ) t o y e l l o w i s h r e d (5Y 5 / 6 ) .
developed sp o d ic h o riz o n s

Th e l e s s

(A uG res-C rosw ell, C rosw ell-G raycalm

and R ubicon) w ere m o s tly w h ite

(5Y 8 / 2 - 8 / 1 ) .

In gen eral,

Nac -DPTA c o l o r s w e r e m o s t l y y e l l o w ( 2 . 5Y - 5Y) w h i l e t h e o t h e r
e x t r a c t a n t s were co m p arab le i n c o l o r ,
Fe e x t r a c t i o n r e s u l t s :

I n g e n e r a l t h e Na2 -NTA c h e l a ­

tin g agent r e s u lte d in the e x tra c tio n

o f s u b s t a n t i a l am ounts

o f e x t r a c t a b l e Fe f r o m m o s t o f t h e s o i l s a m p l e s s t u d i e d
(T able 9 ).

Na2 -EDTA e x t r a c t i n g s o l u t i o n y i e l d e d v e r y low

amounts o f F e ,
less

and N a ^ - p y r o p h o s p h a t e e x t r a c t e d somewhat

t h a n Na2 ~NTA.

The m e t h o d s w e r e m o s t d i v e r s e i n t h e

a m o u n t s o f Fe e x t r a c t e d f r o m t h e R u b i c o n p r o f i l e .
Na^-DPTA e x t r a c t s c o n t a i n e d t r a c e a m o u n t s o f Fe
5
( n e t shown i n T a b l e 9 ) .
As d i s c u s s e d e a r l i e r i n t h e p r e l i ­
minary, s tu d y o f th e e f f e c t
Fe, A l,

o f pH on t h e e x t r a c t a b i l i t y

of

a n d C, t h e lo w q u a n t i t y o f i r o n i n t h e s e e x t r a c t s

was d u e t o t h e h i g h pH o f t h i s
caused the p r e c i p i t a t i o n
If

e x t r a c t a n t , w hich would have

o f Fe a s F e ^ H ) ^ .

only th e e f f e c t

o f pH w e r e t o b e c o n s i d e r e d ,

d a t a r e v e a l s t h a t t h e lo w pH e x t r a c t a n t s h a v e r e s u l t e d

the
in

t h e h i g h e s t amounts of e x t r a c t a b l e Fe; y e t t h e N a ^ -p y ro p h o s phate

(pH=10) h a s a l s o e x t r a c t e d a s much F e a s Na^-EDTA

(pH =4.6).

Furtherm ore,

t h e Na2 -NTA e x t r a c t a b l e Fe i s

54
T a b l e 8.

C olor o f th e sp o d ic B e x t r a c t s by d i f f e r e n t
ex tractan ts

Na2 NTA

M unsell n o t a ti o n s
E xtractant
Na5DPTA
Na2 EDTA N a ^ P ^ y

B2 1 h
B ophir

10YR7/8
10YR7/8

7.57H 5/8
10YR6/8

10YR6/8
2 . 5y7/8

2 .5 7 7 /8
2 .5 7 7 /6

B2 } h i r

10YR 6/8

10YR6/8

10YR6 / 8

2 .5 7 7 /6

B2 2 h i r

10YR7/8

10YR6/8

2 . 577/8

2.577/8

I I B 21h i r '
IIB h ir'm

10YR6/8
2 . 5 Y 7 /8

10YR6/8
2.577/8

2 .577/8
2 .577/8

2 .577/8
2 . 5Y7/8

B2 i h i r
B2 2 h i r

2 . 5 Y 7 /8
-

577/6
578/1

2.5 7 7 /6
577/4

2 . 5Y7/8
5 Y 8/ 4

A1
B2 i i r

5 Y 7 /8
5Y 8/2
5Y 7/ 6

5Y 8/2
577/6
578/1
7-5YR5/8

5Y8/4
577/6
578/2
5YR3/4

2 .5 7/6

577/6

578/3
5Y7 / 6
5Y8 / 2
5YR3/3
2 . 5Y6/8

B2 2 i r

5Y 8/3

578/1

578/1

S o il series;
K inross
S augatuckAu Gre s

AuGresC rosw ell
C rosw ellGraycalm

Rubicon

Hiawatha

H orizon

UPPB2 i h i r
lo w B2 i h i r
B2 2 h i r

Al
B 2ihir

2.577/6
578/3
7 .5 7 R 5 /6 7-5YR5/8
2 . 5Y7/8 2 . 5 7 7 / 8

577/6
5Y 8/2

1 OYR5 / 6

2 .575/6
7 . 5YR5/6 2 . 5 Y 6 / 8
2 . 5Y6 / 6
577/8

Onaway

B2 2 i ^
B2 l i r
B2 2 i r

2 . 5 Y 6 /8
2 . 5 Y 7 /8

2 . 5Y6 / 8
2.577/8

IOYR7 / 8
2 .5 7 7 /6

2 . 577/8
5Y7 / 8

M inising

Al

2.577/6

10YR6/8

5YR3/4

7 . 57R4/4

B2 ^ h i r

5YR5 / 8
2.577/8

5YR5 / 8
2.5Y 7/8

IOYR5 / 6
10Y R6/8

2.5 7 6 /8
577/8

B2 2 i r

55
commonly n o t s i g n i f i c a n t l y h i g h e r t h a n N a ^ - p y r o p h o s p h a t e
e x t r a c t a b l e F e , b u t r a t h e r c o m p a r a b le t o them.
The c h e l a t i n g p o w e r s o f t h e r e a g e n t s a r e d i f f e r e n t .
M a r t e l l and C a l v i n (195*0 g i v e t h e s t a b i l i t y
NTA w i t h F e ++ a s 8 . 8 2 a n d t h a t
Therefore,
lates

EDTA i s

constants

of

o f EDTA w i t h F e ++ a s 1 4 . 3 3 *

c a p a b l e o f f o r m i n g m o re s t a b l e F e c h e ­

c o m p a r e d t o NTA.

In ad d itio n ,

EDTA p o s s e s s e s tw o

donor groups in t h e s t r u c t u r e which re n d e r a s t r o n g e r a b i ­
lity

to c h e la te m etals.

so ils

However,

th e d ata o b tain ed fo r the

s t u d i e d h e r e show m o r e e x t r a c t i o n b y NTA t h a n EDTA i n

a l l sam ples.
Na-DPTA h a s t h r e e d o n o r g r o u p s , t h e h i g h e s t number
5
o f d o n o r g r o u p s among t h e t h r e e o r g a n i c c h e l a t i n g a g e n t s
used in th e study.

T herefore,

l a t e m e ta ls most r e a d i l y .
Nac -DPTA w i t h Fe ++ i s

16. 5.

i t w ould be e x p e c t e d t o c h e ­

The s t a b i l i t y

c o n s t a n t of

As m e n t i o n e d e a r l i e r ,

pH v a l u e may h a v e m a s k e d t h e c h e l a t a b i n t y
ant.
Its

Its

ex tractio n

ab ility

of th is

th e high
ex tract­

o f i r o n was g r e a t l y i m p r o v e d a t pH 1 0 .

t o c h e l a t e aluminum w i l l be d i s c u s s e d l a t e r .

N a^-pyrophosphate i s

an i n o r g a n i c

c h e l a t i n g a g e n t and

h a s r e s u l t e d i n c o m p a r a b l e a m o u n t s o f e x t r a c t a b l e Fe a s
Na2 ~NTA a n d Na2 ~EDTA.
background, th e r e s u l t s

W ith t h e above g e n e r a l i z a t i o n s

as

o b ta in e d f o r each of th e p r o f i l e s

s t u d i e d a r e shown i n T a b l e 9 a n d F i g u r e 2 a n d w i l l b e e x a ­
mined i n t h e f o l l o w i n g p a r a g r a p h s .

56

I

T a b l e 9-

P e r c e n t t o t a l c a r b o n and e x t r a c t a b l e I r o n and al umi num c o n t e n t o f s o i l
samples wi th d i f f e r e n t e x t r a c t i n g s o l u t i o n s ( c h e l a t i n g a g e n t s)

—
%
total
______________________________________ c a r b o n
S oil series

Horizon

Lab §

Extractant
0.1MNa2 'NTA 0.1MNa2 ~EDTA 0 . lMNaaPPO/,
pH=3. 2
pH= 4 . 6
pHSlO
j£Fe
%Fe
% kl
%Fe
^A1

0 . lMKac'DPTA
pH=10
$Fe
S&U

Toposequence:
Kinross
Saugatuck.Au Gres

A
E2 2 h i r

1
2

l.li
. 66

tr.
tr.

. 05

Ep ] Ri r

3
U

0 .27
1.4o
1 40
6°

.11
. 02
.01

.51
. 52
.4 0
. 16

.13
. 05

7
A

1.29

.29

59

• 15

9
10

53
5pci

.16
. l '•
. 0'<

i'2 2 h i r
IIE21h i r 1
I IE Li r 1r.
Au Gres Croswell

B2 i h i r
B2 2 b,ir

CroswellO rayca1m

UPPI'2 j h i r
low B o i h i r
~ •: - :. i r

5
C

11

.09

tr.
tr.

-

.10
.09

tr.
tr.

.08
.06

-

.04
.04

-

.53
. 41
.48
.16

. 33

• 15

.01

.25
.32
.15

. 02
. 02

• 39
.26
.33
.19

. 33
.22

.11
.04

.20
.10

.24
. 0?

.29
.18

-

.34

.23
.21

.05
. 12

.12
.18

.1?

.03

.14
.16
.07

.18
.20
.10

-

.26
.23
.23

.21
.10
. 04

.01

.07

.02

.12

-

.07
.02

.05
.03
.20
.06
.11
.02
.02
.21
.26
.01

.14
• 05

-

.31
.26
.02

• 51
.21
.04

.10
.03
.24
.12
.19
.01
.02
.26
• 35
.02

.21
. 11

.40
.30

.30
.12

. 06

.11
. 06

•05
.02

-

.29
.01

.08

. 01

-

.01

-

.45

.02

.07

.29

Range o f s p o d i c d e v e l o p m e n t :
Omega

B22

12

.44

Eastport
Hut i c o n

£21

13
19

.2"
2 . 5c

. 12
.04

19
1-:
17
1i°
20
21
22

1.07

.23

Ai
B2 1 i r
E2 2 i r
ort s t e i n

Hi awat ha

Onaway

.10
. 01
.05
.03
.04

• 15
.03
.08

-

.44

-

.31
.24
.01
.01
.22
.41
.01

t 22ir

24

.c2
5.40
• 79
2.15
1.3S
1.27
1.45
1.04

B2 2 t
—1

29
£6

1.2“
5.4c.

.40
.oC

.12
. 02

.16
.04

A?

27

1. 3c

• Of

.02

.04

.03
.02

E2 l h i r

2"

3 . 1 ■■

.4“

.4?

■50

.53

.47

Bopi r

2 '‘

1 . :‘2

• 34

.54

. 20

.44

.33

. 46

-

.49

V

30

.45

.07

.07

.04

. 06

.07

.37

-

• 05

A1
A2
Bpihir
E2 2 i r
A2
cvj

Mun isi ng

• 39
.11

. 41
.24

■05
• 05
.56
.27
. 02
.43
.34

• 1?
.02
. 03
.25
.49
.02
.23
.16

• 51
.10
.01
.22
.17

.03
.07

C'O

-

-

.41
.22

57
A. T o p o s e q u e n c e o f p r o f i l e s :
K inross:

The I^-^h a n d

horizons

of K inross

s e r i e s y i e l d e d n e g l i g i b l e a m o u n t s o f Fe u p o n e x t r a c t i o n w i t h
a ll

of th e e x tr a c tin g s o lu tio n s used in t h i s

findings

study.

These

a re in agreem ent w ith a r e c e n t stu d y by C o llin s

( 1 9 7 1 ) i n w h i c h t h e a u t h o r was a b l e t o d e t e c t
Fe i n h i s p y r o p h o s p h a t e e x t r a c t s .

only t r a c e s

T his p r o f i l e i s

of

lo cated

t w e n t y f e e t o u t i n t o a l e a t h e r - l e a f - s p h a g n u m b o g on a n e a r l y
le v e l area w ith poor d ra in a g e.

Th e w a t e r t a b l e i s

a t 6" b e l o w t h e s u r f a c e d u r i n g t h e g r o w i n g s e a s o n .

commonly
I t was

d e v e l o p e d i n r e d u c i n g c o n d i t i o n s w i t h low pH w h e r e a l l
i r o n may b e i n t h e f e r r o u s f o r m s a n d i s
Saugatuck-A uG res:
l e a s e d by a l l

the

l e a c h e d away.

The a m o u n t o f e x t r a c t a b l e F e r e ­

e x t r a c t a n t s were c o n s i d e r a b l y h i g h e r i n

u p p e r s p o d ic h o r i z o n s and d e c r e a s e d w ith d e p t h .

the

Nag-NTA

and N a ^ -p y ro p h o s p h a te e x t r a c t e d t h e h i g h e s t amount o f i r o n
from B ^ ^ h i r and B ^ h i r ,

w h i l e Na2 ~EDTA e x t r a c t e d l e s s

the upper B ^ h i r h o rizo n .

from

The a m o u n t s o f Fe r e l e a s e d b y t h e

t h r e e r e a g e n t s w e r e a l m o s t t h e same f o r b o t h t h e l o w e r Bg
a nd c e m e n t e d s p o d i c h o r i z o n s , I T E ^ ^ h i r 1 a n d I I B h i r ' m .
s i d e r i n g t h e m o i s t u r e regim e of th e p r o f i l e
th a t the in te r n a l drainage i s

Con­

and t h e f a c t

im p e rfe c t, w ith the w ater

t a b l e a t an a v e ra g e d e p th of 2 8 " d u rin g th e grow ing s e a s o n ,
th e data c l e a r l y

sho ws t h a t t h e l o w e r c e m e n t e d h o r i z o n s f r o m

l6"-33" are le ss

a e r a t e d as th e r e s u l t of th e p re s e n c e of a

SAUGATUCK -AU GRES

RUBICON

S B hir'm

ONAWAY

Orfstein

.10

.20

.30
% Fe

.40

.50

.10

.20
% Fe

.30

.10

.40

HIAWATHA

CROSWELL-GRAYCALM

.2 0

.30
% Fe

.40

.50

MUNISING

cn
00

2
upp B 2 ihi r

hir

low B2 , hi r

ir

822^*1

nt
F ig.

3x

.10

.20
%Fe

2.

.30

.10

.20

.3 0
% Fe

.40

.50

.60

.10

.2 0

.3 0
% Fe

E x t r a c t a b l e ir o n c o n te n t o f s e l e c t e d h o riz o n s o f pedons s t u d i e d u sin g
d ifferen t e x tra cta n ts.

.40

.5 0

mmmmsmtmmmfm'm’

SAUGATUCK -AU GRES

ONAWAY

RUBICON

B21 hir

Bgghir
IT 8 2 1 hir'
I I B hir'm

Orlstein

.10

.20

.30
% AP

.4 0

.5 0.55

.20

.30
% AP

.40

.50

.10

.20
.30
%AP
MUNISING

HIAWATHA

CROSWELL-GRAYCALM

.40

ui

VD

upp B 2 1 hir

621 hir

.10

.2 0

% AP

F ig.

3.

.3 0

.10

.20

.3 0
% AP

.40

.50

.2 0

.30

.40

% AP

E x t r a c t a b l e a l u m in u m c o n t e n t o f s e l e c t e d h o r i z o n s o f p e d o n s s t u d i e d
using d i f f e r e n t e x tr a c ta n ts .

.5 0

.60

6o

w ater ta b le .

C onsequently, th e p r e v a i l i n g red u cin g c o n d i­

t i o n s h a v e r e s u l t e d i n l o w e r Fe c o n t e n t .

The Fe ma xima i s

in th e u p p e r s p o d ic developm ent w ith f i n e r t e x t u r e .
tractab le

iro n in th is p r o f ile

Th e e x ­

decreased w ith depth i n th e

spodic h o riz o n .
A uG res-C rosw ell:

Among t h e t h r e e e x t r a c t a n t s

the

Na^-NTA e x t r a c t e d t h e l a r g e s t a m o u n t o f i r o n .
Na, - p y r o p h o s £
4
p h a t e a n d Na^-EDTA r e l e a s e d t h e i n t e r m e d i a t e a n d l o w e s t
amounts o f F e ,
taken i s

respectively.

The s i t e w h e r e t h e s a m p l e was

a b e t t e r d rain ed lo c a tio n w ith a d rain ag e c la s s

im p erfect to m oderately w e ll d ra in e d .

of

The d e p t h o f t h e

w a te r t a b l e a v e ra g e s 36 " d u r in g th e grow ing s e a so n .

The Fe

maximum o c c u r s i n t h e s p o d i c h o r i z o n s o m e w h e r e i n t h e u p p e r
B2 h i r a n d d e c r e a s e s i n t h e l o w e r p a r t o f t h i s
C rosw ell-G raycalm :

The Fe maximum o c c u r s i n t h e

l o w e r B2 ]_hir i n t h e l o c a t i o n f r o m w h i c h t h i s
taken.

horizon.

s a m p l e was

The Na2 -NTA a n d N a ^ - p y r o p h o s p h a t e r e l e a s e d t h e same

amounts o f i r o n from t h i s

h o r i z o n w h i l e Na -EDTA e x t r a c t e d

th e l o w e s t amounts of Fe.
b e tte r drained s i t e

in th is

This p r o f i l e

is

toposequence.

located a t a
It

i s m oderately

w e l l d r a i n e d w ith t h e w a t e r t a b l e a t an a v e r a g e d e p th
d u rin g t h e grow ing s e a s o n .

The e x t r a c t i o n

o f Fe i s

of 58"

low er

i n t h e B2 2 h i r h o r i z o n .
Summary:

The e x t r a c t i o n d a t a o v e r a l l shows a h i g h

a c c u m u la tio n o f Fe i n a l l t h e s p o d ic h o r i z o n s

of the s o i l s

6l

i n t h i s t o p o s e q u e n c e e x c e p t t h e v e r y p o o r l y d r a i n e d m e m be r,
K inross.

Th e maximum a c c u m u l a t i o n i s

d r a i n e d me mbers ( C o l l i n s ,
B.

P ro files

i n t h e somewhat p o o r l y

1971).

r e p r e s e n t i n g range of sp o d ic developm ent:

The s e c o n d g r o u p o f s o i l s

in c lu d e s a range of spodic

h o r i z o n d e v e lo p m e n t from t h e w e a k e s t t o t h e s t r o n g e s t d e v e l ­
op m e nt i n M i c h i g a n ( L i e t z k e ,
ex tractio n

1969).

The r e s u l t s

o f t h e Fe

f o r t h e s e s o i l s a r e summarized i n t h e f o l l o w i n g

paragraphs.
Omega:

The B22 h o r i z o n o f Omega s e r i e s

contained a

l a r g e p r o p o r t i o n o f Na2 - N T A - e x t r a c t a b l e Fe a s c o m p a r e d t o
Na^-EDTA a n d N a ^ - p y r o p h o s p h a t e .
r e l e a s e d only very l i t t l e
E astp o rt:

The l a t t e r t w o e x t r a c t a n t s

i r o n from t h i s p a r t i c u l a r h o r i z o n .

B21 e x t r a c t a b l e F e c o n t e n t w i t h t h e c h e l a ­

tin g agents used in t h i s

s t u d y was g e n e r a l l y h i g h e r i n com­

p a r i s o n w i t h Omega B2 2 .

The e x t r a c t a b i l i t y

reagents in a decreasing

order i s

o f i r o n by th e s e

as fo llo w s :

N a ^ - p y r o p h o s p h a t e = Na2 -NTA^> Nag-EDTA
Rubicon:
th is

A]_, B2 ^ i r , B2 2 i r a n d o r t s t e i n h o r i z o n s

of

s o i l s e r i e s were s u b j e c t e d t o e x t r a c t i o n w ith th e c h e ­

la tin g agents.

E x c e p t f o r t h e A^ h o r i z o n s w h e r e b o t h N a^-

p y r o p h o s p h a t e a n d Na,-,-NTA y i e l d e d s i m i l a r s m a l l q u a n t i t i e s
e x tra c ta b le Fe,

of

t h e e x t r a c t i o n p a t t e r n f o l l o w e d t h e same

g e n e r a l t r e n d i n t h a t Na2 -NTA e x t r a c t e d t h e h i g h e s t q u a n t i t y

62

o f F e , Na2 -EDTA t h e l o w e s t a m o u n t , a n d N a ^ - p y r o p h o s p h a t e
interm ediate q u a n titie s .

Th e a m o u n t o f e x t r a c t a b l e F e f r o m

th e o r t s t e i n h o riz o n l i e s betw een t h a t
horizons.

o f B2 1 i r

a n d B2 2 i r

O r t s t e i n o c c u r s a t a d e p t h r a n g i n g f r o m 9" t o 2 7 "

w ith chunks or tongues 1 1 /2 " -3 " t h i c k ,
W h ite s id e and J o h n so n ( 1 9 6 7 ).

as d e s c r i b e d by

This s o i l g ives r i s e

F e maxima d u e t o t h e p r e s e n c e o f o r t s t e i n ,

t o two

i n which e x t r a c t -

a b l e Fe c o n t e n t o f t h e s e c o n d z o n e o f maxima i s

considerably

l o w e r t h a n t h e f i r s t Fe maxima i n t h e B2 1 i r h o r i z o n .
H iaw atha:
z on o f t h i s
an ts.

Th e p e r c e n t Fe e x t r a c t e d f r o m e a c h h o r i ­

so il is

The

q u ite s im ila r fo r the d i f f e r e n t e x t r a c t ­

a n d A2 h o r i z o n s y i e l d e d t h e l o w e s t v a l u e s

w h i l e t h e maximum e x t r a c t a b l e Fe o c c u r r e d i n t h e B2 l h i r h o r i ­
z on w h e r e t h e s p o d i c h o r i z o n e x p r e s s i o n i s
in th e f ie ld .

q u i t e pronounced

Th e d i f f e r e n c e s i n t h e a m o u n t s o f e x t r a c t a b l e

Fe o b t a i n e d w i t h t h e s o l u t i o n s u s e d i n t h i s
n o t i c e a b l e i n t h e B2 2 i r h o r i z o n .

s tu d y were q u i t e

The o r d e r o f e x t r a c t i o n i s

sh ew n b e l o w :
Nag-NTA - N a ^ - p y r o p h o s p h a

Na2 -EDTA

T h is s o i l i s w e l l d r a i n e d and has b e e n c l a s s i f i e d a s a T ypic
H a p l o r t h o d a c c o r d i n g t o 19 67 c l a s s i f i c a t i o n s .
ch aracteristics
field .

and m orphology a r e e a s i l y

The s p o d i c

observable in the

The h i g h c o n t e n t o f e x t r a c t a b l e F e a l s o c o n f i r m s t h i s

s tr o n g developm ent.

63
!

Onaway:
th is

The A2 , B

ir, B ^ ir,

a n d B2 2 t h o r i z o n s

of

s o i l s e r i e s w e r e s t u d i e d f o r e x t r a c t a b l e Fe c o n t e n t .

The r e s u l t s

s h ow e d t w o F e m a x im a .
T h e s e o c c u r r e d i n B2 -^ir
r
a n d t h e a r g i l l i c h o r i z o n B2 2 t wlrien Na^-NTA was u s e d a s t h e
ex tractan t.

The o t h e r t w o e x t r a c t a n t s ,

N a ^ -p y ro p h o s p h a te and

Na2 -EDTA, r e s u l t e d i n o n l y on e Fe maximum i n t h e B ^ i r h o r i ­
zon.

Na2 -EDTA e x t r a c t e d t h e l o w e s t a m o u n t o f Fe f r o m t h e

B2 i r ,

w hile s im ila r ,

larg er q u an tities

o f e x t r a c t a b l e Fe

w e r e o b t a i n e d w i t h N a ^ - p y r o p h o s p h a t e a n d Na2 ~NTA s o l u t i o n s .
As m e n t i o n e d e a r l i e r ,

t h e N T A - e x t r a c t a b l e Fe c o n t e n t f r o m

t

B2 2 t was c o n s i d e r a b l y h i g h e r t h a n t h e a m o u n t e x t r a c t e d w i t h
the other s o lu tio n s .
clay p a r tic le s

T h i s may b e d u e t o t h e f a c t t h a t t h e

in th is p a r t i c u l a r horizon (c la y c o n ten t =

2 4 . 9 $ ) w e re more s e r i o u s l y a f f e c t e d by t h i s
O th e r forms o f F e ,

acid s o lu tio n .

in a d d itio n to those c h a r a c t e r i s t i c

sp o d ic h o r i z o n s , were e x t r a c t e d as w e l l .

of

The o t h e r s o l u ­

t i o n s , w i t h h i g h e r p H ' s , w ere more s p e c i f i c

as t o t h e form

of iro n b ein g e x tra c te d .
M unising:

E x c e p t f o r t h e B2 2 i r h o r i z o n , w h i c h

yield ed d iff e r e n t q u a n titie s

o f e x t r a c t a b l e Fe w i t h t h e e x ­

tractan ts

all

so il

used in th e stu d y ,

re s u lte d in the re le a s e

the oth er horizons

of s i m i l a r q u a n t i t i e s

w ith th e th re e c h e la tin g agents used.

of th is
o f Fe

The A , A2 a n d f r a g i -

p a n B^x c o n t a i n e d t h e l o w e s t e x t r a c t a b l e F e c o n t e n t s .
B2 l h i r h o r i z o n c o n t a i n e d t h e h i g h e s t a m o u n t .

The

Therefore,

an

64
F e maxima o c c u r r e d i n t h i s h o r i z o n n e a r t h e t o p .
has more c l a y c o n t e n t t h r o u g h o u t t h e p r o f i l e

T his s o i l

a s c o m p a r e d mo

H i a w a t h a , y e t t h e e x t r a c t a b l e Fe c o n t e n t o f t h e s p o d i c h o r i ­
zon i s

q u i t e com parable t o t h a t of H iaw atha.
Aluminum e x t r a c t i o n r e s u l t s :

The e x t r a c t i o n o f A1

w ith th e c h e la tin g agents used in t h i s
g e n e r a l p a t t e r n as t h a t

s t u d y f o l l o w t h e same

o f F e , T a b l e 9? F i g u r e 3 j e x c e p t t h a t

s u b s t a n t i a l q u a n t i t i e s w e r e e x t r a c t e d b y Na^-DPTA.
I n c o n t r a s t t o Fe e x t r a c t i o n ,

a c o n s i d e r a b l e amount of

A l was e x t r a c t e d f r o m a l m o s t a l l t h e s o i l s w i t h a h i g h pH
Na,--DPTA s o l u t i o n .

T h i s was p a r t i c u l a r l y t r u e

o f t h e Onaway,

S augatuck-A uG res, Rubicon, and C ro sw ell-G ray calm ped o n s.
Na^-NTA e x t r a c t e d m o r e A l a s c o m p a r e d t o N a ^ - p y r o p h o s p h a t e
a n d Na2 ~EDTA e x t r a c t a n t s .

However, t h e m a g n itu d e o f d i f f e r ­

e n c e s a r e m a r k e d l y h i g h e r w i t h t h e B2 ]_ir a n d B2;- , i r h o r i z o n s
o f R u bicon and C r o s w e ll- G r a y c a lm p e d o n s .

The o t h e r p e d o n s

d o n o t show a c o n s i s t e n t d i f f e r e n c e i n t h e a m o u n t o f e x t r a c t a b le Al w ith th e d i f f e r e n t

ex tractan ts,

although th e re

ex ists

a v e ry p ro n o u n c e d v a r i a t i o n i n t h e amount of e x t r a c t a b l e Al
from h o r i z o n t o h o r i z o n w i t h i n a p r o f i l e .
is

e v id e n t i n th e low er B g ir h o r iz o n s .

This r e l a t i o n s h i p

The p r o f i l e v a r i a t i o n s

w i l l be d i s c u s s e d i n more d e t a i l i n t h e f o l l o w i n g p a r a g r a p h s .
D a t a on s o l u b i l i t y

of Al i n s o l u t i o n s

a t d i f f e r e n t pH

v a lu e s i s g iv e n by M a g is ta d (1 9 2 5 ), J a c k s o n ( 1961) ,
( i 9 6 0 ).

and R ich

The s u g g e s t e d b e h a v i o r o f A l i n r e s p o n s e t o v a r i o u s

65
pH v a l u e s i n d i c a t e t h a t i n s t r o n g l y a c i d s o l u t i o n t h e A l
ex ists

as t h e t r i v a l e n t c a t i o n complex w i t h s i x w a t e r m o le ­

cules in s ix c o o rd in a tio n s,
(1961)

form ing A l(H 20)^p.

Jackson

d e s i g n a t e s t h e r e s u l t i n g t r i v a l e n t i o n complex

"alum inohexahydronium ".

W i t h i n c r e a s i n g pH t h e H2 O g r o u p s

l o s e a n H* i o n t o f o r m a n OH

ion.

This r e s u l t s

in d i-

or

m ono-valent hydroxy-Al c a ti o n s w ith th e form ula
A l ( 0 H 2 )p_(0H) +2 a n d A1(0H2 ) ^ ( 0H)2 + 1 , r e s p e c t i v e l y .
subsequent in c re a se s
w ill re su lt.

W ith

i n pH t h e p r e c i p i t a t i o n A l ( O H ) 0 H 2 ) ^

H o w e v e r , f u r t h e r i n c r e a s e i n pH w i l l s o l u b i l i z e

A l b y f o r m a t i o n o f A l( O H ) g

.

T h e r e f o r e t h e h i g h e r amounts of

A l e x t r a c t e d b y Na^-DPTA may b e a r e f l e c t i o n
a s s o c ia te d w ith t h i s

o f t h e h i g h pH

e x tractan t.

The a m o u n t o f A l e x t r a c t e d b y a l l t h e c h e l a t i n g a g e n t s
m a rk e d ly e x c e e d s t h e c o r r e s p o n d i n g amounts o f e x t r a c t a b l e Fe.
This i s

i n a g re em e n t w i t h M a r t i n and Reeve ( 1 9 5 7 ) .

These

a u t h o r s p o s t u l a t e t h a t t h e h i g h e r c o n t e n t of e x t r a c t a b l e Al
may b e a r e f l e c t i o n
present in a l l

of th e excess

so ils.

o f t o t a l A l o v e r t o t a l Fe

C onsequently i t

is

d i f f i c u l t t o assume

t h a t Al h a s a p r e d o m in a n t i n f l u e n c e i n c o m b in in g w i t h t h e
organic

fractio n .
The f r e e i r o n

oxide c o n te n ts

a nd t h e t o t a l

A l o f some o f t h e p e d o n s u s e d i n t h e s t u d y ,
lab o rato ry ,

a r e shown i n T a b l e 1 0 .

exchangeable

d e t e r m i n e d b y SCS

The o r t h o p h e n a n t h r o l i n e

c o l o r i m e t r y a n d f l u o r i d e t i t r a t i o n m e t h o d s a r e u s e d f o r Fe

66

oxide and exchangeable Al determination, respectively.

The

data shows that, except for the Onaway B21ir and B22ir hori­
zons, the spodic B horizons have higher contents of Al com­
pared with Fe.

Al exceeds Fe six to seven times in the case

of Munising Bpqhir and B22ir.

These results may serve to

confirm the validity of Martin and Reeve's postulate.
The results of the extractable Al for all the pedons
are further discussed in the following paragraphs.
A.

Toposequence of profiles:
Kinross:

The Bpqh and B22hir horizons released more

Al upon extraction with the chelating agents as compared with
Fe, but the extractable Al was also lowest in this poorly
drained member of the toposequence.

The extractable Al of

this soil is comparable with all four extractants used.
From the very low amounts of extractable Fe it seems that Fe
plays little or no

part in stabilizing organic matter in

this poorly drained soil.

It is therefore concluded that Al

is the "active" metal involved in stabilizing the organic
fraction in the spodic horizon of this soil.
Saugatuck-AuGres: The amount of Al extracted by the
chelating reagents is quite diverse.
more Al than any other horizon.

The Bpqhir released

The effect of the extracting

solutions on the amount of extractable Al is as follows:
A1-DPTA> Al-NTA

Al-pyrophosphata> Al-EDTA

67
T a b le 10.

S o il series

P e r c e n t f r e e i r o n oxide and t o t a l ex ch a n g e ab le
A l o f some o f t h e s o i l p e d o n s u s e d i n t h e s t u d y
by o r t h o p h e n a n t h r o l i n e c o l o r i m e t r y and f l u o r i d e
t i t r a t i o n methods

and h o r i z o n

T o ta l i r o n oxide
a s % Fe

% Exchangea b l e Al

Omega

B22

0.40

0 .4 0

Eastport

i—
i
CM
PQ

0.30

0.10

Al

0.20

0.60

B2 1 i r

0.50

i . 4o

B 2 2 ^-r

0.20

0.40

ortstein

0.20

0.50

Al

0.40

0.10

A2

o . 4o

0.30

B2ihir

1.10

2.40

E^ir

o.6o

1.90

a2

0.50

0.40

B2iir

1 .7 0

i . 4o

Bgpir

1.40

1.00

B2 2 t

2.00

trace

A1

o . 4o

0.30

A2

0.40

0.90

B22hir

1.00

6.10

B22ir

0.60

4.00

b 3x

o .4o

1.20

Rubicon

Hiawatha

Onaway

Munising

68

The h o r i z o n w i t h t h e n e x t h i g h e s t e x t r a c t a b l e a m o u n t o f A l
was I I B 2 ] _ h i r ' .

The E ^ h i r h a s an i n t e r m e d i a t e amount o f

e x t r a c t a b l e A l , w h i l e t h e I I B h i r ' m y i e l d e d t h e l e a s t amount
of Al upon e x t r a c t i o n .

T h e d a t a s u g g e s t t h a t A l was l o s t

f r o m t h e B2 2 h i r h o r i z o n a n d a c c u m u l a t e d i n t h e I I B g ^ h i r ' ,
p r o b a b l y c o m p l e x e d a nd f i x e d w i t h o r g a n i c m a t t e r .

The

B ^ h i r and I I B ^ h i r 1 e x t r a c t a b l e Al c o n t e n t s w ere q u i t e d i ­
v e r s e u p o n DPTA, NTA a n d p y r o p h o s p h a t e e x t r a c t i o n *

w hile

EDTA e x t r a c t e d t h e same a m o u n t o f A l a s p y r o p h o s p h a t e .
A uG res-C rosw ell:

The DPTA e x t r a c t a b l e Al f r o m t h e

B g i h i r a n d B2 2 h i r h o r i z o n s w e r e g r e a t e s t *
t r a c t e d t h e l e a s t amount o f A l.

w h i l e EDTA e x ­

The o t h e r tw o e x t r a c t i n g

s o l u t i o n s r e s u l t e d i n i n t e r m e d i a t e amounts of e x t r a c t a b l e
A l.

I n e v e r y c a s e t h e B ^ h i r h a d m o r e e x t r a c t a b l e A l com­

p a re d w ith th e low er B ^ h i r h o riz o n .
C rosw ell-G raycalm :

The maximum e x t r a c t a b l e A l

o c c u r r e d i n t h e l o w e r B2 q h i r when EDTA a n d p y r o p h o s p h a t e w e r e
u s e d a s t h e e x t r a c t i n g a g e n t s , w h i l e t h e maximum o c c u r r e d i n
t h e u p p e r B p ^ h i r w i t h DPTA a n d NTA.

In general,

t h e DPTA

s o l u t i o n e x t r a c t e d t h e h i g h e s t amount o f Al from a l l h o r i ­
zons,
order.

f o l l o w e d b y NTA, p y r o p h o s p h a t e ,

a n d EDTA, i n d e c r e a s i n g

The a m o u n t o f A l e x t r a c t e d was l e s s

in t h is w ell

d r a i n e d member o f t h e t o p o s e q u e n c e t h a n i n t h e s o m e w h a t
p o o r l y d r a i n e d member.

69

B.

Profiles representing range of spodic development:
Omega:

Al.

The B22 had a high amount of DPTA extractable

The NTA extractable Al was intermediate, while EDTA and

pyrophosphate extracted lower amounts of Al.
Eastport:

The B21 horizon had a high DPTA extract-

able Al content as compared with other extracting solutions.
NTA and pyrophosphate extracted the same intermediate amounts
of Al from this horizon, and EDTA the least.
Rubicon:

The A-j_, B^ir, B ^ i r and an ortstein were

subjected to extraction by the chelating agents.

The A^ had

a trace amount of extractable Al with all of the reagents
used.

Maximum Al occurred in the B21ir horizon.

The B22ir

contained less extractable Al compared to the upper B22ir.
Ortstein had an intermediate amount of extractable Al.

This

drop in the amount of Al in the B22ir and its subsequent
increase in the ortstein was only evident with EDTA and
pyrophosphate extractions.

DPTA and NTA showed a continuous

decrease in the amount of extractable Al from the B22ir hori­
zon downward.

DPTA and NTA extracted more Al from the B2^ir

horizon compared to Al extracted from the same horizon by
EDTA and pyrophosphate.
Hiawatha:

The A^ and A2 horizons contained traces of

extractable Al with all the extracting agents used.

The

B ^hir had the less extractable Al than the lower B22ir.
NTA resulted in the maximum extractable Al from the B22ir,

70
f o l l o w e d b y DPTA, p y r o p h o s p h a t e ,
order.

a n d EDTA i n d e c r e a s i n g

The d a t a s u g g e s t t h a t t h e A l h a d b e e n t r a n s l o c a t e d

deeper in t h i s p r o f i l e th a n i n th e o th e r pedons s tu d ie d ,
where t h e e x t r a c t a b l e Al u s u a l l y d e c r e a s e s w i t h d e p t h .
Onaway:

The A2 h o r i z o n c o n t a i n e d t r a c e s

of e x t r a c t-

a b l e Al w i t h a l l t h e e x t r a c t i n g s o l u t i o n s .
t r a c t a b l e A l o c c u r r e d i n t h e B2 1 i r ;
an a r g i l l i c
®22^-r '

horizon;

Th e maximum e x t
t h e l o w e s t i n t h e B2 2 t ,

and i n t e r m e d i a t e e x t r a c t a b l e Al i n th e

g e n e r a l> t h e DPTA e x t r a c t a b l e Al c o n t e n t was c o n ­

s i d e r a b l y h i g h e r t h a n t h e c o r r e s p o n d i n g EDTA e x t r a c t a b l e A l ,
w h i l e p y r o p h o s p h a t e a n d NTA s o l u t i o n s r e l e a s e d i n t e r m e d i a t e
amounts o f A l.
M unising:

The A-j_, A , a n d t h e f r a g i p a n h o r i z o n s c o n ­

t a i n e d v e r y lo w q u a n t i t i e s

of e x t r a c t a b l e A l.

The h i g h e s t

a m o u n t o f A l o c c u r r e d i n t h e B2 ^ h i r a n d B g ^ i r h o r i z o n s .
The d i s t r i b u t i o n

o f e x t r a c t a b l e Al depended upon t h e e x t r a c t ­

ing ag en t used.

Upon e x t r a c t i o n w i t h N a ^ - p y r o p h o s p h a t e a n d

Na^-EDTA, t h e maximum o c c u r r e d i n t h e B2 -j_hir, w h i l e NTA r e ­
s u l t e d i n maximum e x t r a c t a b l e A l i n t h e B2 2 i r .

DPTA e x ­

t r a c t e d t h e same a m o u n t f r o m b o t h t h e B0 -^hi r a n d B2 2 i r
h orizons.
Carbon e x t r a c t i o n r e s u l t s :

The t o t a l c a r b o n c o n t e n t

of th e s o i l s used, b e fo re e x tr a c tio n w ith d i f f e r e n t c h e la tin g
agents,

a r e shown i n T a b l e 9-

s am p les and l a c k o f c a r b o n a t e s ,

(Due t o t h e lo w pH o f t h e s o i l
th e t o t a l carbon is

tak en to

71
be equal to th e organic carbon p r e s e n t in th e s o i l . )

The

e x t r a c t a b l e c a r b o n was o b t a i n e d f r o m t h e d i f f e r e n c e i n c a r ­
bon betw een th e n o n - t r e a t e d
so il,

(o rig in al)

a s shown i n T a b l e 1 1 .

s o i l and t h e t r e a t e d

Th e f a c t t h a t some c a r b o n m e a s ­

u rem en ts were g r e a t e r a f t e r e x t r a c t i o n i s
w i l l be d isc u sse d l a t e r .

a p e c u lia rity th at

Th e p e r c e n t o f t o t a l c a r b o n e x ­

t r a c t e d by th e d i f f e r e n t e x t r a c t a n t s a r e a l s o c a l c u l a t e d in
T a b le 11.

Wh ere c a r b o n m e a s u r e d d i d n o t c h a n g e o r i n c r e a s e d

w ith e x t r a c t i o n , no f i g u r e i s

g iv e n and a d a s h i s

In a d d i tio n to spodic h o riz o n s ,
A ^ , A2 ,

o rtstein ,

arg illic

su b stitu ted .

o t h e r h o r iz o n s su ch as

and f r a g i p a n were s u b j e c t e d t o e x ­

t r a c t i o n by t h e d i f f e r e n t c h e l a t i n g a g e n t s .
The h i g h o r g a n i c m a t t e r s u r f a c e h o r i z o n s ,

su ch as

R u b i c o n A ^ , H i a w a t h a A ^ , a n d M u n i s i n g A^ h a v e v e r y l i t t l e
tr a c t a b l e carbon.

ex­

H o w e v e r , t h e h i g h pH Na^-DPTA s o l u t i o n e x ­

t r a c t e d a s much a s 2 2 $ o f t h e t o t a l c a r b o n f r o m M u n i s i n g A^.
In g en eral,

it

used in t h i s

can be c o n clu d e d t h a t th e c h e l a t i n g e x t r a c t a n t s

study a re n o t s p e c if ic

m atter p re sen t in surface s o i l,
efficien cy

of e x tra c tio n

t o t h e form o f o r g a n ic

a s e v i d e n t b y t h e v e r y low

o f s u c h m a t e r i a l s , T a b l e 11.

A2 h o r i z o n s u s e d i n t h e s t u d y a r e low i n i n i t i a l
ten t.

The

carbon con­

Th e H i a w a t h a A2 d i d n o t y i e l d a n y e x t r a c t a b l e c a r b o n .

The o t h e r

horizons

tiv e ly higher contents

(Onaway a n d M u n i s i n g ) , w h i c h h a v e r e l a ­
of organic carbon, y ie ld e d sm all

amounts o f e x t r a c t a b l e c a r b o n .

72

T a b l e 1 1.

P e r c e n t o f t o t a l c a r b o n a f t e r e x t r a c t i o n , p e r c e n t e x t r a c t a b l e c a r b o n , and
th e p e r c e n t o f t o t a l carbon e x t r a c t e d by t h e d i f f e r e n t e x t r a c t a n t s used
In t h i s stu d y
E xtractan ts

S o il series

H orizons

Kinross

SaugatuckAuGr es

AuGresCroswell
C rosw ellGraycalm

Omega
Eastport
R u b l e on

Na2 -NTA
-------------------------------------------#C a f t e r $ e x t . % o f
extracc(l)
to ta l C
tlo n
e x t .(2 )
.70

. 41
. 27

37
40

.77
.05

.34
.61

30
92

.73
.77

. 3 8 37

.3°

E? ] h i r

1 .78

I .03 75
c; q

1.13

1.12

4y

.79

37

1 .27

F-2 2 h i r
I I B 21h i r
I I B h i r ' ■■

.*7

t-4
57
a

.77
.7]
.76 1 . 00
.77
-

r

. 20

.>*1
. --4
. 49

-

•5
.67
• o2

Bo/iir

. 62

.67

51

.7 k

72

.62

F22n i r

59

-

.37

. 22 37

.57

UPPE2 1 h i r
Low B2 1 h i r
E2 2 h i r

t■0

. 53
.57

. 5 8 50
. 12 1 8

.78 1.79 65

. 7 9 97
.07
-

.77
. 70
.97

.70 k [
.76 92
. 1 9 21

.77

3fc

.79

. 90 38

.05

-

.79

. 1 0 16

. 47

.05

11

• 37

.16

30

.70

_

_

_

34

.11

12

66

-

-

-

-

30

.77
.37

.77
QQ

-

.30
-

-

.78

-

-

.58

-

-

-

I-22

-

-

. 3'-'

-

-

.82

-

-

.77

-

-

-

-

■7 k

-

-

.71

-

-

.£'9

-

-

2.3"
1 . :,2
.37

. 06

r.

A1
E2 1 i r
B2 2 i r

Ai

2 . 99

.11

4
17

. 54

• 15
.23

5. 1 “
7"

.37

. 66

. 22

4

7.93

-

-

. 72

1 . 02

7 :-

1.37

*"3

E22^-r

1 .20

. 1 ''

13

a2
E2 1 i r

1 .25

. 02

1

] .13

'7
(' 2

.11
.42

41

•7s
,?7

■"1

.k k

-

■. , 4 3

B2ihir

P22 i r
'~ 2 2 t

Munising

-

Na^-DPTA
-------------------

B21

a2

Onaway

Na4 - P 2 0 .,
-----------------------

B22*^r

ortstein
Hiawatha

Na2 -EDTA
-----------------------

’2

Ai
A-

7.4-

E2 1 h i r

1.11

^2 2 ^r
e 3x

1.1/
7
.40

.17
2 . )■:

12

1.14

59
11

.05

. 10

6

2.85

.11

7

2.50

. 05

-

1.10

-

-

.82

-

-

. 76

-

-

.58

-

.70

-

-

.66

.37

6

-

-

.k 7
-

5.03

-

1 . 1 3 52
• 32 1 . 0 2 73

• 97 1 . 2 1

-

-

2 . 6 7 2 . 5 3 47
1. 90
1.1

. '-7 4n
. 67 4f

. -1

.77

56
37

.1*+ 11

1.20

.07

6

1.16

. 11

. 70 77

. 6 0 70
.02
-

1.06

kk

.88
1.02

1.00

. 7 2 23
.07
-

, a7 ( 7

1.12

.16

12

1.23

• 05

-

8. 6 0

-

. 77 o7

1.2.6

-

2 . 3 1 72
. 6 1' 1 . 2 3 67
.24

. 'OP

■29 23
-

. 2 1 76

1.16 2.01

-

63
. 7 9 1 . 1 3 96
.76
-

.77

-

7 . 2 6 1 . 21 22
1.36

-

-

1 . 06 2 . 1 3 66
. 66 1 . 0 6 55
.79

-

( 1 ) C a l c u l a t e d from t h e d i f f e r e n c e b e t w e e n t h e o r i g i n a l ( T a b l e 9 ) and t h e t r e a t e d s a m p l e s .
D a s h e s I n d i c a t e w h ere n e g a t i v e v a l u e s w e r e r e c o r d e d .
( 2 ) P e r c e n t e x t r a c t a b l e c a r b o n d i v i d e d by p e r c e n t t o t a l o r i g i n a l c a r b o n ( T a b l e 9 ) x 1 0 0 .

-

73
The o n l y e x t r a c t a n t c a p a b l e o f d i s p e r s i n g c a r b o n f r o m
t h e o r t s t e i n h o r i z o n o f t h e R u b i c o n p e d o n was t h e a c i d i c
u t i o n o f Na2 -NTA ( p H = 3 . 2 ) .
to tal

so l­

T h i r t y - s e v e n p e r c e n t of th e

organic carbon of t h i s

h o r i z o n was e x t r a c t e d b y Na2 -NTA.

T h is e x t r a c t a n t a l s o r e s u l t e d i n r e l a t i v e l y h i g h amounts of
Fe and Al from t h i s
fore,

horizon,

as d i s c u s s e d p r e v i o u s l y .

There­

Na2 -NTA may h a v e d i s t u r b e d t h e a s s o c i a t i o n b e t w e e n s e s -

q u i o x i d e s and o r g a n i c m a t t e r and c o n s e q u e n t l y r e s u l t e d i n
hig h er carbon e x tr a c tio n .
The low pH e x t r a c t a n t s

a p p e a r e d t o b e more e f f e c t i v e

i n e x t r a c t i n g c a r b o n from t h e a r g i l l i c
Onaway p e d o n .
of the t o t a l

(B2 2 t )

h o riz o n of th e

Na2 -EDTA a n d Na2 -NTA e x t r a c t e d 6 5 $ a n d 51$
organic carbon,

resu lted in ex tractio n

resp ectiv ely .

o f 12$ of th e t o t a l

N a^pyrophosphate
c a rb o n and th e

h i g h e s t pH e x t r a c t a n t r e s u l t e d i n a v e r y m i n u t e a m o u n t o f e x ­
t r a c t a b l e carbon.

This p a r t i c u l a r h o riz o n c o n ta in s

2 4 . 9 $ c l a y and i t c a n be p o s t u l a t e d t h a t t h e a c i d i c
ants

released

about
ex tract­

o r g a n i c m a t t e r a d s o r b e d on c l a y s u r f a c e s .

Na^-EDTA a p p e a r e d t o b e t h e m o s t e f f e c t i v e
o f c a r b o n from t h e f r a g i p a n h o r i z o n o f M u n is in g .

ex tractan t
F o rty -six

p e r c e n t o f t h e t o t a l c a r b o n was e x t r a c t e d b y t h i s c h e l a t i n g
agent.

Na^-NTA r e s u l t e d i n c o n s i d e r a b l y l e s s

organic carbon.

Th e o t h e r e x t r a c t a n t s

extractab le

did n o t r e s u l t in

d i s p e r s i o n and c o n se q u e n t e x t r a c t i o n o f o rg a n ic
M unising f r a g ip a n .

c a r b o n from

7^
In general,

th e su b -su rfa ce horizons i n i t i a l l y

low i n

organic carbon c o n te n t d id n o t respond to th e e x tr a c ti n g
so lu tio n s,
sity

regardless

of t h e i r i n t e r n a l d ra in a g e or i n t e n ­

of e x p r e s s io n of pedogenic p r o c e s s e s .

I n c l u d e d among

t h o s e h o r i z o n s a r e C r o s w e l l - G r a y c a l m B2 2 h i r ,
E a s t p o r t B2 1 , a n d R u b i c o n B2 2 i r .

The o r g a n i c c a r b o n c o n t e n t

of th e se s o ils p r io r to e x tra c tio n are
. 33, re s p e c tiv e ly .

Omega B2 2 ,

.25>

. 2 8 , and

More o r g a n i c c a r b o n was d e t e c t e d i n

t h e s e sam p le s a f t e r t h e s o i l s w ere s u b j e c t e d t o d i f f e r e n t ex
tractan ts,
nic carbon.

r e s u l t i n g i n n e g a t i v e amounts o f e x t r a c t a b l e
The p o s s i b i l i t y

orga

o f t h e a d s o r p t i o n o f some o f

th e c h e la tin g ag en ts by s o i l p a r t i c l e s

d o e s n o t s ee m t o b e

valid

since th ese s o ils

It

a l s o e v i d e n t f r o m t h e p r e c i s i o n o f d e t e r m i n a t i o n on

is

rep licates

c o n ta in very l i t t l e c la y p a r t i c l e s .

o f t h e same s a m p l e t h a t t h e v a r i a t i o n i s n o t s u f ­

f i c i e n t to obscure carbon changes in th e s e s o i l s .

The c a r ­

bon e x t r a c t i o n r e s u l t s w i l l be f u r t h e r examined as f o ll o w s :
K inross:

From l 8 / o - 9 2 $ o f t h e t o t a l c a r b o n o f t h e

B2 1 h a n d B2 2 h i r h o r i z o n s

of th i s

s o i l s e r i e s was e x t r a c t e d

by t h e c h e l a t i n g a g e n t s u sed i n t h i s

study.

However, Na^-

p y r o p h o s p h a t e d i d n o t e x t r a c t a n y c a r b o n f r o m t h e BQ2h i r
horizon.
Saugatuck-A uG res:

The m o r e a c i d i c

ex tractan ts

(Na2 ~NTA a n d Na2 -EDTA) w e r e m o re e f f i c i e n t i n e x t r a c t i o n o f
o r g a n ic c a r b o n from t h e lo w er B h o r i z o n s ,

s u c h a s B2 2 h i r ,

75
I I B g h i r ' , and I I B h i r 'm .

H o w e v e r , t h e u p p e r B (B2 1 h i r )

gave

h i g h e r r e c o v e r i e s w i t h t h e h i g h pH Na^-DPTA e x t r a c t a n t .
g eneral,

In

f r o m 2 1 $ t o 71 $ o f t h e t o t a l o r g a n i c c a r b o n was e x ­

t r a c t e d by th e f o u r c h e l a t i n g a g e n ts used i n th e s tu d y .
A uG res-C rosw ell:

The l o w pH e x t r a c t a n t s

r e m o v e d m o r e c a r b o n t h a n t h e h i g h pH e x t r a c t a n t s
B2 p h i r h o r i z o n o f t h i s

so il series.

(NTA, EDTA)
from t h e

In the b e t t e r drained

C r o s w e l l - G r a y c a l m h i g h pH s o l u t i o n s ( p P q I j . 5DPTA) w e r e u n a b l e
to e x tra ct d etectab le q u a n titie s

of carbon.

H i a w a t h a B ^ h i r a n d M u n i s i n g B2 1 h i r r e s u l t e d

in the

h i g h e s t p e r c e n t a g e o f t o t a l c a rb o n e x t r a c t e d by a l l t h e e x ­
tractan ts

used.

However, t h e B p p i r h o r i z o n s

c o n t a i n so m e w h a t l e s s

e x tra c ta b le carbon.

d a ta w ith th o s e of s u r f a c e h o riz o n s
appears t h a t th e se e x tr a c ta n ts

of th e se s o i l s

Com paring t h e s e

o f t h e same s o i l s ,

it

a r e much m o r e s p e c i f i c

to the

forms o f o r g a n ic m a t t e r e l u v i a t e d from t h e u p p e r p a r t

of the

so ils.
The Onaway B2 ^ i r h o r i z o n was a l s o e x t r a c t e d e f f i ­
c i e n t l y by th e e x t r a c t a n t s ,
bon w ere removed.

a l t h o u g h l e s s e r amounts of c a r ­

In g en eral,

t h e low pH e x t r a c t a n t s

appear

t o b e so m ew ha t m o r e e f f i c i e n t i n e x t r a c t i n g t h e i l l u v i a l
carbon.
S ta tis tic a l an aly ses:

The d a t a w e r e s t a t i s t i c a l l y

a n aly z e d u s in g a C o n tro l D ata C o rp o ra tio n
com puter.

(CDC) 3 6 0 0 d i g i t a l

The M i c h i g a n S t a t e A g r i c u l t u r a l e x p e r i m e n t

76
s t a t i o n STAT r o u t i n e s w e r e u s e d .

The e x t r a c t a b l e F e , A l

and C by d i f f e r e n t e x t r a c t a n t s were s u b j e c t e d t o a n a l y s i s
variance.

Th e t w o - w a y a n a l y s i s

was u s e d f o r Fe a n d A l .
and e x t r a c t a n t .

of variance w ith in te r a c t io n

The c a t e g o r i e s w e r e s o i l h o r i z o n s

T h e d e s i g n u s e d f o r c a r b o n was t h e same e x ­

c e p t f o r t h e u se o f t h e m ethod o f f i t t e d
fo r th e h ig h ly unbalanced d a ta .
the data is

shown i n T a b l e 1 2 .

d i f f e r e n c e s due t o s o i l s
cant a t the

Y fo

of

lev el.

constants

A nalysis

of t h e v a r i a n c e of

The F t e s t

and e x t r a c t a n t s

to account

shows t h a t t h e

are highly s i g n i f i ­

However, t h e s t a t i s t i c a l

an aly sis

f a i l e d t o show a s i g n i f i c a n t d i f f e r e n c e f o r c a r b o n d u e t o
d iffe re n t ex tractan ts

a t t h e 1 % a n d 5$ l e v e l s .

The T u k e y ' s W - p r o c e d u r e was u s e d t o c o m p a r e t h e t r e a t ­
ment means.

The f o l l o w i n g c o n c l u s i o n s a r e drawn from t h e

com putation of th e d a ta .
Th e r e s u l t s

f o r Fe e x t r a c t i o n r e v e a l t h a t t h e r e was a

s i g n i f i c a n t d i f f e r e n c e b etw een t h e e x t r a c t i n g power of th e
NTA, p y r o p h o s p h a t e ,

a n d EDTA e x t r a c t a n t s

a t t h e 5% l e v e l .

The t r e a t m e n t m e a n s a r e r a n k e d i n a n i n c r e a s i n g o r d e r a n d
the r e s u lts

o f t h e T u k e y ' s t e s t f o r Fe w i t h l e a s t s i g n i f i c a n t

r a n g e (LSR)

(5 /0 = -0265 can be summarized as f o l l o w s :

NTA

pP0||

EDTA

.1673

.1383

.0973

The t h r e e m e a n s a r e s i g n i f i c a n t l y d i f f e r e n t .

T a b l e 12.

A n a l y s i s of v a r i a n c e of t h e e x t r a c t a b l e F e , Al and c a r b o n

Fe
Source of v a ria n c e

d .f.

Soils
E xtractant

Al
M.S.

c

d .f.

M.S.

d .f.

M .S.
0 . 1 8 8 8 **

29

0.1107**

29

0.1705**

23

2

0.0742**

3

0 . 0 9 9 0 **

3

0 . 0 0 8 2 MS

S o il ex tracta n t

58

0.0036

87

0.0053

45d )

0.0398

R em aining e r r o r

90

0.0004

120

0.0006

72

0.0009

T otal

179

239

143

NS = n o t s i g n i f i c a n t a t t h e 5 $ l e v e l
( l ) = d e g re e of freedom
com binations.

f o r i n t e r a c t i o n r e d u c e d ow ing t o m i s s i n g t r e a t m e n t

78
The T u k e y ' s t e s t f o r A l w i t h ISR ( 5 $ ) = * 0 3 4 8 i s

sum­

m a riz e d below :
DPTA

NTA

. 2 4 0 7 ____________. 2 1 1 7

pPO ^

EDTA

.1780

.1470

( a n y t w o m e a n s n o t u n d e r s c o r e d b y t h e same l i n e a r e s i g n i f i ­
can tly d iff e r e n t.)

The r e s u l t s

a n d DPTA e x t r a c t a n t s

show t h a t a l t h o u g h t h e NTA

r e s u lt in higher e x tra c tio n

of A l,

the

d i f f e r e n c e s b e t w e e n th e m a r e n o t s i g n i f i c a n t a t t h e 5$ l e v e l .
H o w e v e r , t h e DPTA r e s u l t s a r e s i g n i f i c a n t l y d i f f e r e n t f r o m
th e pyrophosphate e x tr a c ti o n r e s u l t s .
not sig n ific a n tly

The l a t t e r i s

d i f f e r e n t f r o m t h e EDTA r e s u l t s .

f e r e n c e s b e t w e e n NTA a n d pPO^ i s

also
Th e d i f ­

approaching s ig n if ic a n c e

a t t h e 5$. l e v e l .
A m o d i f i e d T u k e y " s LSR ( 5 $ ) was u s e d f o r c o m p a r i s o n
o f t h e c a r b o n t r e a t m e n t means due t o u n b a l a n c e d number o f
o b s e r v a t i o n s i n e a c h t r e a t m e n t mean.
is

G e n e r a l l y T u k e y ' s LSR

d e f i n e d by e q u a t i o n
W = q « ( P , n ) Sx

¥ = LSR
q«(P , n) i s

a f a c t o r o b t a i n e d from a t a b l e

percentage p o in ts

of upper

of th e s tu d e n tiz e d range

w ith p t r e a t m e n t , n e r r o r d e g re e o f freedom
a n d a n o< e r r o r r a t e .
S x = s t a n d a r d e r r o r o f t h e mean

79
I n t h e c a s e o f u n e q u a l o b s e r v a t i o n s on e a c h mean a m o d i f i c a ­
tio n is

su g g e ste d by Sokal and R o h lf ( 1969) as:
Sx =

where

S

2

S2

nl + n2
2n^2

= varian ce of in d iv id u a ls

n ^ = n u m b e r o b s e r v e d on t h e f i r s t m ean i n
th e com parison
n 2 = n u m b e r o b s e r v e d on t h e s e c o n d mean i n
th e com parison.
Th e t w o l o w pH e x t r a c t a n t s d e m o n s t r a t e d t h e g r e a t e s t
e ff ic ie n c y in e x tr a c tio n of carbon.
th e m a r e s i g n i f i c a n t a t t h e 5 % l e v e l .
resu lts

The d i f f e r e n c e s b e t w e e n
The EDTA e x t r a c t a n t

a r e a l s o s i g n i f i c a n t l y d i f f e r e n t f r o m t h e h i g h pH

p y r o p h o s p h a t e a n d DPTA e x t r a c t a n t s , w h i l e t h e NTA i s n o t .
Th e T u k e y ' s t e s t

f o r c arb o n e x t r a c t i o n can b e sum m arized as

follow s:
EDTA

NTA

pPO^

. 5117

. 3 7 1 7 _________ . 3 4 1 7 _________ . 2 9 1 7

( a n y t w o m e a n s n o t u n d e r s c o r e d b y t h e same l i n e

DPTA

are s i g n i f i ­

c antly d i f f e r e n t . )
The a b o v e s t a t i s t i c a l a n a l y s i s r e v e a l s t h a t DPTA
e x t r a c t e d t h e h i g h e s t a m o u n t s o f A l , a n d EDTA t h e h i g h e s t
amounts o f c a r b o n from t h e s p o d ic h o r i z o n s u s e d i n t h i s
study.

However, t h e f o r m e r i s n o t a s u i t a b l e e x t r a c t a n t f o r

Fe due t o i t s

h i g h pH, a n d t h e l a t t e r e x t r a c t e d t h e l o w e s t

80
a m o u n t s o f Fe a n d A l f r o m t h e s o i l s

used.

T herefore,

e x t r a c t a n t which r e s u l t e d i n t h e m ost e f f e c t i v e

the

ex tractio n

o f F e , A l , a n d c a r b o n f r o m t h e s p o d i c h o r i z o n s u s e d was t h e
low pH,

. 1M Na2 ~NTA.
C lassificatio n

of th e s o i l s :

The p e d o n s u s e d i n t h i s

study a re c l a s s i f i e d a cc o rd in g to th e c r i t e r i a
t h e new s o i l c l a s s i f i c a t i o n
and as g iv e n by C o l l i n s

system

( S o i l T a xono m y , 1 9 7 0 , u n e d . )

(1971) and L i e t z k e ( 19 6 8 ) , a s f o l l o w s :

(1)

K inross (o rg an ic s u rfa c e ):
san d y , m ixed, f r i g i d .

(2)

S a u g a tu ck -A u G res: A e rie H aplaquod;
m ixed, f r i g i d , o r t s t e i n .

sandy,

(3)

A uG res-C rosw ell:
m ixed, f r i g i d .

sandy,

(4)

C rosw ell-G raycalm :
m ixed, f r i g i d .

(5)

Omega:

(6 )

E astp o rt:

(7)

R ubicon:
frig id .

(8)

H iaw atha:
frig id .

(9 )

On awa y:
frig id .

(10)

H i s t i c H aplaquod;

E n tic Sideraquod;

E ntic H aplorthod; sandy,

T y p ic U dipsamment; m ix e d , f r i g i d .
S p o d ic U dipsamment; m ix e d , f r i g i d .
E n tic H aplorthod;
Typic H a p lo r th o d ;
A lfic

H aplorthod;

san d y , m ixed,
san d y , m ixed,
f in e - lo a m y , m ixed,

M unising: A lfic F rag io rth o d ; coarse-loam y,
m ixed, f r i g i d .

The c h e m i c a l c r i t e r i a
considered in th is
ratio

explained in

for c la ssific a tio n

of S podosols

stu d y a re th e accu m u latio n in d e x and th e

o f % p y r o p h o s p h a t e e x t r a c t a b l e Fe a n d Al t o % c l a y ,

81
T a b l e 13 .

The i n d e x o f a c c u m u l a t i o n i s

CEC(pH 8 . 2 )
index i s

expressed as

tim es th ic k n e s s

- 1/2$ c la y

i n cm. = 6 5 .

This

a m e a s u r e o f t h e amount o f amorphous m a t e r i a l i n

th e spodic h o riz o n .

The c a l c u l a t i o n o f t h e i n d e x i s b a s e d

on t h e c o n s i d e r a t i o n o f t h e h i g h c a t i o n e x c h a n g e c a p a c i t y o f
t h e amorphous m a t e r i a l ,
of th e h o rizo n .

as w e l l as t h e $ c l a y and t h i c k n e s s

T h i s w o u l d s e t some l o w e r l i m i t f o r t h e

amount o f p r e c i p i t a t e d i l l u v i a l m a t e r i a l .

The $ c l a y i s

s i d e r e d in an a tte m p t to c o r r e c t f o r t h a t p a r t
change c a p a c i t y which i s
sent in the s o il.

of th e e x ­

a fu n ctio n of the s i l i c a t e

clay pre

Th e r e a s o n f o r t h e c o n s i d e r a t i o n o f t h e

s o il horizon th ic k n e ss i s
tio n

con

to e v alu a te the v e r t i c a l d i s t r i b u ­

o f t h e amorphous m a t e r i a l i n t h e s p o d ic h o r i z o n .
The c r i t e r i o n

o f t h e % p y r o p h o s p h a t e e x t r a c t a b l e Fe

and Al o v e r % c l a y b e i n g e q u a l o r g r e a t e r t h a n
sub-horizon,

.2 ,

i n some

i s b a s e d on t h e f a c t t h a t t h e e x t r a c t i o n w i t h

p y r o p h o s p h a t e a t pH=10 i s

s e l e c t i v e f o r t h e co mp oun ds t h a t

a re t y p i c a l of spodic h o riz o n s.

Furtherm ore,

s in c e sm all

amounts o f s e s q u i o x i d e s a r e a s s o c i a t e d w i t h c l a y s u r f a c e s
or o t h e r amorphous m a t e r i a l s p r e s e n t i n t h e s o i l ,

the %

c l a y i s c o n s i d e r e d t o a ll o w f o r t h e a d s o r b e d i r o n and alu m ­
inum o x i d e s .
T a b l e 13 shows t h e a b o v e r a t i o s a n d t h e Fe a n d A l / $
clay r a t i o s w ith o th er c h e la tin g agents s u b s tit u te d fo r
pyrophosphate.

The s p o d i c h o r i z o n s s t u d i e d g e n e r a l l y a g r e e

82
w ith th e re q u ire d accum ulation in d ex .

However, t h e e x c e p ­

t i o n s a r e Omega a n d E a s t p o r t .
Most o f t h e s o i l s

do n o t m eet t h e r e q u i r e d r a t i o

% e x t r a c t a b l e Fe a n d k \ / % c l a y .

This i s p a r t i c u l a r l y tru e

w ith th e h ig h ly ex p re ssed spodic h o riz o n s in th e f i e l d ,
as M unising.
l o w e r Fe +
ants.

In general,

of

such

EDTA e x t r a c t i o n h a s r e s u l t e d i n a

A l /% c l a y

ratio

ascompared w ith th e o th e r e x t r a c t

Th e NTA, pPO^ a n d DPTA r a t i o s

a re f a i r l y com parable.

The c h a n g e s o f t h e % Fe + A l t o fo c l a y w i t h i n t h e
p r o f i l e can be f u r t h e r summarized as f o l l o w s :
(1)
Au Gre s

I n tw o o f

the

so ilp ro files,

and H iaw ath a, t h e r a t i o

w ith d epth.

namely S a u g a tu ck -

o f Fe + k l / % c l a y i n c r e a s e d

Th e h i g h e r r a t i o s w e r e o b s e r v e d i n t h e l o w e r

spodic s u b - h o r iz o n s .
(2) I n A u G res-C rosw ell t h e h i g h e r r a t i o

o f Fe + k l / %

c la y o ccu rred in th e upper spodic B h o riz o n .
( 3 ) I n K i n r o s s , Onaway, a n d M u n i s i n g ,

t h e Fe + A l

t o % c l a y rem ained c o n s t a n t th ro u g h o u t th e p r o f i l e .
(4) I n C rosw ell-G raycalm th e r a t i o

of Fe + A l/% c l a y

in c re a s e d to a c e r t a i n d epth (low er B p p h ir).

Beyond t h a t

depth th e r a t i o d e c re a se d .
( 5 ) R u b i c o n s how e d a d e c r e a s e o f t h e r a t i o w i t h
d e p t h w i t h EDTA a n d p y r o p h o s p h a t e e x t r a c t i o n .
NTA a n d DPTA e x t r a c t i o n s
out th e p r o f i l e .

However, t h e

re s u lte d in a co n stan t r a tio

through

83
T a b le 13.

Th e a c c u m u l a t i o n i n d e x a n d t h e p e r c e n t e x t r a c t a b l e Pe p l u s Al o v e r % c l a y b y d i f f e r e n t e x t r a c t ­
a n ts of spodic h o riz o n s used i n t h i s stu d y

—
S o il S eries

H orizon

K inross

Bpih
B2 2 h i r

Acc.

index

E x t r a c t a n t and % Fe +
$ Al/% c l a y
NTA EDTA pPO^ DPTA
.05
.04

.05
.03

.04
.05

.02
.02

65.3
109.1
227.1
135.1

.0 8
.06
.13
.15

.05
.05
.11
.15

.07
.05
.11
.20

.08
.07
.16
.17

181.4
79.6

Saugatuck-A uG res

B2 i h i r
B2 2 h i r
IIB g ih ir1
IIB h ir'm

A uG res-C rosw ell

B2 i h i r
B2 2 h i r

64.7
44.8

.14
.08

.07
.03

.12
. 06

• 13
.08

C r o s w e l l - Graycalm

UppB2 1 h i r 6 . 0
lo w B2 i_hi r 3 2 . 5
B22 b i r
45 .5

.08
.11
.07

.04
.08
.03

. 06
.10
. 06

.08
.11
.11

Omega

B22

19.3

.11

.02

.05

.11

E astport

B21

28.2

.17

.10

.18

• 30

Rubicon

B2 l i r
Al
B2 2 i r
o rtstein

82.8
64.9
27.3
-

.17
.02
.16
.33

.08
.01
.03
.17

.11
.02
.07
.2 8

.16
.004
.16
.35

Hiawatha

Al
B2 i h i r
B2 2 i r

78.5
97-5
172.9

.02
.12
.32

.01
.10
.15

.01
.11
.28

.002
.11
.27

Onaway

B2 i i r
B2 2 i r
B2 2 t

65.5
34.6
46.0

.04
.03
.0 2

.0 2
.0 2
.01

.04
.03
.01

.05
.05
.01

M unising

Al
B2 i h i r
B2 2 i r

61.3
209.2
221.4

.0 2
.09
.11

.0 2
.10
.08

.02
.10
.10

.002
.09
.1 1

20.8

.03

.0 2

• 03

.01

B3 x

84
From t h e c o n s i d e r a t i o n o f t h e a b o v e c r i t e r i a ,
highly d e s ir a b le to s e t a lim it fo r th e r a t i o
% clay to prevent the exclusion

horizons

it

is

o f Fe & A l /

of th e w e ll-d e v e lo p e d spodic

observable in th e f i e l d .

This i s p a r t i c u l a r l y tr u e

f o r t h o s e w i t h a low e x t r a c t a b l e Fe a n d A l c o n t e n t o r h i g h
p e r c e n t a g e o f c l a y , which t e n d t o lo w er t h e r a t i o below t h e
c u rre n tly accepted re q u ire d v alue.
the r a t i o
dosols

I t is

suggested to

o f Fe & A l / / c l a y t o = 0 . 1 0 t o i n c l u d e m o s t S p o -

(A uG res-C rosw ell, C rosw ell-G raycalm ,

The same r a t i o i s
drained,

and M u n isin g ).

s u g g e s t e d t o be s e t a t = .04 f o r t h e w e l l -

f i n e - t e x t u r e d S p o d o s o ls as w e l l as th e p o o r l y -

d ra in e d Spodosols

(Onaway a n d K i n r o s s s e r i e s ) .

The o l d e r c h e m i c a l c r i t e r i a
fo r the r a t i o

f o r spodic h o rizo n s c a l l s

of % t o t a l carbon or % e x tr a c ta b le carbon,

e x t r a c t a b l e F e , and % e x t r a c t a b l e Al over % c l a y .
e x t r a c t a n t s w e r e u s e d f o r Fe a n d Al e x t r a c t i o n .
q uently,

low er

%

D ifferen t
Conse­

d i f f e r e n t l i m i t s were p ro p o se d ( L i e t z k e ,

1968).

S u c h r a t i o s w e r e s e t a t = . 1 2 when t o t a l c a r b o n a n d a c i d
ammonium o x a l a t e was u s e d .

T a b l e 14 s hows t h e r a t i o

of /

t o t a l c a r b o n p l u s % e x t r a c t a b l e Fe a n d A l o v e r % c l a y w i t h
th e e x tr a c ta n ts used in t h i s

study.

e x t r a c t a b l e Fe a n d A l o f L i e t z k e i s
parison.

The a v a i l a b l e

oxalate

a l s o i n c l u d e d f o r com­

A ll of th e sp o d ic h o riz o n s u sed i n th e stu d y meet

t h e r e q u i r e d r a t i o i n some s u b - h o r i z o n .
one o f t h e m a i n c o n s t i t u e n t s

S ince carbon is

of th e i l l u v i a l m a te ria l of th e

85
spodic h o riz o n in th e s e s o i l s ,

it

is

suggested t h a t th e

r a t i o h e u s e d i n p r e f e r e n c e t o t h e % Fe & A l / / c l a y r a t i o
c u rre n tly in use.

86
T able 14.

Th e r a t i o o f % t o t a l C, % e x t r a c t a b l e F e , a n d
fo e x t r a c t a b l e A l o v e r % c l a y f o r s p o d i c h o r i z o n s
used in th e study

S o il S eries

H orizon

E x t r a c t a n t a n d $ C + $ f ’e +
% A l/ % clay
_______
NTA EDTA
PPO4
DPTA O x a l a l

K inross

B2 i h
B2 2 h i r

.58
.40

.58
.39

• 57
.41

.55
.38

B2 1 h i r
B2 2 h i r
IIB 2]_hir'
IIB h ir'm

.33
.28
.60
.77

.30
.27
.58
.77

.32
.27
.58
.82

.33
•29
.63
• 79

B 2lhir
B2 2 h i r

.44
.20

.37
• 15

.42
.1 8

.43
.20

U p p .B 2 i h i r
lo w B2 ]_ hir
B2 2 h i r

.19
• 35
.16

.15
.32
.12

.17
.34
.15

.19
• 35
.20

—

b 22

.26
.38

.17
• 31

.2 0
• 39

.26
• 51

• 25
.37

.45
.31
1.01

.36
.18
.85

• 39
.22
• 96

.44
.31
1.03

.4 0
• 29
1.08

.38
.41

B22i r

.40
.43
.9 2

• 75

.39
.42
.88

• 36
.42
.87

a2
B2 1 i r
B2 2 i r
B2 2 t

.30
.13
.10
.07

.30
.11
.09
. 06

.31
• 13
.10
. 06

.29
.14
.12
.06

3.7
.40
.32
.1 2

3.7
.40
• 34
.13

3.3
.39
.35
.11

Saugatuck-A uG res

A uG res-C rosw ell
C rosw ell-G raycalm

Omega
E astport

B21

Rubicon

B2 i i r
B2 2 i r
o rtstein

Hiawatha

a2

B 2ihir
Onaway

M unising

a2

B 2ihir
Bp2 i r
B^x

3.8
.39
.35
.13

-

—

-

_

.44
.78
.15
.13
-

-

.40
.33
-

SUMMARY AND CONCLUSIONS

T h i s r e s e a r c h was i n i t i a t e d t o s t u d y t h e d e g r e e o f
accum ulation of th e i l l u v i a l m a te r ia l,

as m easured by d i f ­

f e r e n t e x t r a c t i n g m edia and i n f l u e n c e d by p e d o l o g i c a l p r o ­
c e s s e s and s o i l fo rm a tio n f a c t o r s ,
dosols.
is

in the B horizons

The i l l u v i a l m a t e r i a l o f i n t e r e s t

(activ e m aterial)

c o n s i d e r e d t o b e composed o f s e s q u i o x i d e s

t h o s e o f Fe a n d A l ) a n d o r g a n i c m a t t e r .

o f Spo-

(p articu larly

The f o l l o w i n g c o n ­

c l u s i o n s may b e d r a w n f r o m t h e d i s c u s s i o n o f t h e r e s u l t s .
S o i l d r a i n a g e and t h e i l l u v i a l m a t e r i a l :
g ib le q u a n titie s

The n e g l i ­

o f e x t r a c t a b l e Fe i n t h e e x t r a c t s

of poorly-

d r a i n e d K i n r o s s s o i l may b e e x p l a i n e d b y c o n s i d e r i n g t h e
follow ing p o s s i b i l i t i e s :

( l ) Since th e w ater ta b le i s

c l o s e t o t h e s u r f a c e and i t

commonly a v e r a g e s 6 i n c h e s b e ­

lo w t h e s u r f a c e d u r i n g t h e g r o w i n g s e a s o n ,
th a t th e p r e c i p i t a t i o n
occasional flu sh es

(2)

it

is

un lik ely

o f i r o n o x id e s have o c c u r re d by

of oxy g en ated w a te r which o x i d i z e f e r r o u s

compo und s a n d d e c r e a s e t h e i r s o l u b i l i t y .
sib ility

very

However, t h e p o s ­

of m i c r o b i a l o x i d a t i o n s h o u ld a l s o be c o n s id e r e d .

The p r e s e n c e o f t h e p r e v a i l i n g r e d u c i n g c o n d i t i o n s p r o ­

b ab ly have r e s u l t e d in th e occurence of th e ir o n in th e r e ­
d u c e d (Fe"*-*") f o r m .

C onsequently i t could have been le ac h e d

away f r o m t h e s u b - s o i l ,

since th a t is

t h e more s o l u b l e form

88

of iro n .

T h i s phenomenon c a n h e s u p p o r t e d by D e b 's

(19^9)

s t u d y i n w h i c h t h e a u t h o r c o n c l u d e s t h a t t h e l o w pH o f m o s t
p o d z o l s p r e c l u d e s t h e e x i s t e n c e o f a n y i r o n a s Fe
is

4-4-

, which

so lu b le a t those re a c tio n s .
The d a t a o b t a i n e d i n t h i s

s t u d y shows t h e a m o u n t s o f

e x t r a c t a b l e Fe from t h e p o o r l y d r a i n e d K in r o s s s u b s o i l i s
n eg lig ib le,
Therefore i t

e v e n when t h e l o w pH e x t r a c t a n t s w e r e u s e d .
in v a lid a te s th e p o s s ib ility

th e o x id iz e d Fe.

Furtherm ore,

it

is

of th e e x is t e n c e of

s u g g e s t e d t h a t A1 may

be a ss ig n e d a m ajor r o l e in s t a b i l i z i n g th e o rg a n ic m a tte r
in the B h o rizo n s

of th is

so il,

although th e q u a n titie s

of

e x t r a c t a b l e A1 a r e a l s o low i n t h e s u b s o i l o f K i n r o s s .
The b e t t e r - d r a i n e d s o i l s

of t h i s

drainage caten a are

shown t o h a v e a h i g h e r a m o u n t o f e x t r a c t a b l e F e .

Th e i m p e r ­

f e c t l y - d r a i n e d S a u g a tu c k - A u G r e s c o n t a i n s more e x t r a c t a b l e
Fe i n t h e u p p e r B h o r i z o n , a n d d e c r e a s i n g a m o u n t s i n t h e
low er B h o r i z o n , where t h e low er p a r t

of th is

h o riz o n occurs

a t th e av erage observed depth to th e w a ter t a b l e .

The

A u G r e s - C r o s w e l l maximum e x t r a c t a b l e Fe o c c u r s i n t h e u p p e r
B h o riz o n , w h ile C rosw ell-G raycalm has i t s
u l a t i o n i n th e low er B h o riz o n .
o f t h e l a t t e r tw o s o i l s
a b le organic m a tte r,
those h o rizo n s.

maximum Fe a c c u m ­

The maximum e x t r a c t a b l e Fe

c o r r e l a t e w i t h t h e maximum e x t r a c t -

s u g g e s t i n g g r e a t e r complex f o r m a t i o n i n

Among t h e s o i l s

of t h i s

to p o s e q u e n c e , AuGres-

C rosw ell has e x h ib ite d th e h ig h e s t e x t r a c t a b l e Fe.

However,

89

t h i s i s n o t in agreem ent w ith th e g r e a t e s t e x t r a c t a b i l i t y

of

o r g a n i c m a t t e r i n t h e t o p o s e q u e n c e , aid c o n s e q u e n t l y t h e
highest in te n s ity

of spodic h o riz o n developm ent, as w i l l be

seen l a t e r in t h i s

chapter.

Th e m a g n i t u d e o f t h e A1 e x t r a c t e d b y a l l

of the che­

l a t i n g a g e n t s e q u a ls o r e x ce e d s t h e c o r r e s p o n d i n g amounts o f
i r o n e x t r a c t e d from t h e s p o d i c h o r i z o n s i n a l l t h e s o i l s
s t u d i e d e x c e p t E a s t p o r t , Hiawatha I ^ h i r ,
may b e a r e f l e c t i o n

a n d Onaway.

This

o f t h e g r e a t e r i n v o l v e m e n t o f A1 i n

c h e la tio n r e a c tio n s w ith organic m a tte r ,
t o t a l A1 o v e r Fe p r e s e n t i n t h e s o i l .

or th e ex cess

of th e

The l a t t e r p o s s i b i l i t y

may b e m o r e v a l i d s i n c e t h e e x c h a n g e a b l e A1 e q u a l s

or ex ceeds,

the t o t a l c i t r a t e - d i t h i o n i t e

e x tr a c ta b le Fe,

E a s t p o r t a n d Onaway p e d o n s .

In th e p o o rly -d ra in e d K inross

so il i t

is

d e f i n i t e l y shown t h a t A1 i s

except in th e

th e m ajor elem ent

a s s o c ia te d w ith th e e x tr a c ta b le o rganic m a tte r.
is d if f ic u lt

However, i t

t o s a y w hich m e ta l h a s t h e p re d o m in a n t i n f l u e n c e

in com bining w ith th e o rg a n ic f r a c t i o n

of th e spodic h o riz o n s

of th e oth er s o i l s .
The a m o u n t s o f A1 do n o t seem t o b e i n f l u e n c e d b y
d r a i n a g e a s much a s F e .

However, t h e p o o r l y - d r a i n e d K i n r o s s

s o i l c o n t a i n s t h e l o w e s t a m o u n t o f e x t r a c t a b l e A1 w h i l e t h e
so m ew ha t p o o r l y d r a i n e d S a u g a t u c k - A u G r e s h a s t h e h i g h e s t
e x t r a c t a b l e A l , w i t h tw o m a x im a , t h e s e c o n d maxima b e i n g
a s s o c ia te d w ith a d i f f e r e n t p a re n t m a te r ia l,

IIB 2 .

The h i g h

90
c o n t e n t o f A1 i n S a u g a t u c k - A u G r e s c o r r e l a t e s w i t h t h e h i g h
accum ulation of organic m a tte r as w e ll as th e i n t e n s i t y of
spodic h o riz o n developm ent i n t h i s
It

is

so il.

a p p a r e n t from t h e e x t r a c t i o n d a t a t h a t c o n s i ­

d e r a b l e amounts o f t h e B h o r i z o n o r g a n ic m a t t e r a r e a s s o ­
c ia te d w ith a f r a c tio n of the t o t a l s e s q u io x id e s .

F u rth er­

m ore, i t

are spe­

cific

is

evident th a t the c h e la tin g e x tra c ta n ts

to the e x tr a c tio n

B horizons,

of th e organic m a tte r p r e s e n t i n th e

s i n c e v e r y s m a l l amounts o f c a r b o n w ere e x t r a c t e d

from t h e s u r f a c e A h o r i z o n .
Spodosols

of v a rio u s d eg rees of spodic h o riz o n

d ev elo p m en t and t h e i l l u v i a l m a t e r i a l :
plexed iro n in c re a s e s

The a m o u n t o f com-

from t h e w e a k e s t s p o d ic h o r i z o n e x p r e s ­

sio n to th e s t r o n g e s t developm ent.

Th e maximum e x t r a c t a b l e

Fe o c c u r s i n t h e u p p e r B h o r i z o n i n a l l t h e s o i l s
group.

of th is

The Omega a n d E a s t p o r t , w h i c h a r e c l a s s i f i e d a s

T ypic Udipsamments

(Brown P o d z o l i c s o i l )

ment (R e g o so l Po d zo l i n t e r g r a d e ) ,
lo w e s t amounts of e x t r a c t a b l e Fe.
spodosols,

and S p o d ic U dipsam-

resp ectiv ely ,

c o n ta in the

O th e r more d e v e l o p e d

such as R ubicon, H iaw atha,

and M u n isin g s e r i e s ,

c o n t a i n h i g h e r amounts o f e x t r a c t a b l e Fe.
The a m o u n t s o f e x t r a c t a b l e A1 show t h e same t r e n d a s
Fe,

i n w hich i t

developm ent.

in c re a s e s w ith the i n te n s ity

of p e d o lo g ic a l

The A1 a n d Fe maxima o c c u r i n t h e s am e h o r i ­

z o n ( B ^ ^ i r ) i n R u b i c o n a n d Onaway s o i l s e r i e s , w h i l e t h i s i s

91
n o t th e c a s e w ith H iaw atha and M u n isin g .

In th e l a t t e r the

maximum A1 o c c u r s d e e p e r i n t h e p r o f i l e , n a m e l y i n t h e l o w e r
s p o d i c B h o r i z o n (B2 2 i r )*

E x t r a c t a h l e Fe i s c o n s i d e r a b l y

p r e d o m i n a n t i n t h e Onaway a n d M u n i s i n g p r o f i l e s , w h i l e A1
i s p re d o m in a n t i n t h e R ubicon and H iaw atha p r o f i l e s .

However,

H i a w a t h a B2 i h i r d a s m o r e e x t r a c t a b l e Fe c o m p a r e d t o A l .
A h i g h p e r c e n t a g e "of e x t r a c t a b l e c a r b o n , a s c a l c u l a t e d
from t h e d i f f e r e n c e b e tw e e n t h e n o n - e x t r a c t e d and e x t r a c t e d
so ils,

occurs in th e spodic h o riz o n s .

t r u e in s u b s o ils w ith a high i n i t i a l

This i s

esp ecially

carbon c o n te n t.

The

e x t r a c t a b l e C maximum o c c u r s a t t h e same h o r i z o n ( B g i i r )
Fe a n d A l maxima i n R u b i c o n a n d Onaway s e r i e s .

of

However,

H i a w a t h a a n d M u n i s h i n g e x t r a c t a b l e C a n d F e maxima o c c u r
a t the upper B h o rizo n
a t th e low er B ^ i r
nant ro le

(B2 p h i r ) w h i l e t h e A l maximum o c c u r s

horizon.

T h i s may s u g g e s t t h e p r e d o m i ­

o f Fe i n t h e s e s o i l s

in the s o l u b i l i t y

of organic

m atter.
S ta tis tic a l an alyses:

The s t a t i s t i c a l

analysis

of

t h e e x t r a c t i o n d a t a r e v e a l s t h a t t h e NTA, pPO^, a n d EDTA
e x t r a c t i o n p r o c e d u r e s f o r Fe p r o d u c e r e s u l t s w i t h s i g n i f i ­
c a n t d i f f e r e n c e s b e tw ee n them.

The e x t r a c t a b l e F e , EDTA

v a lu e s a r e s i g n i f i c a n t l y low er th a n th e o th e r e x t r a c t a n t s .
The ETA e x t r a c t a b l e Fe i s

i n d i c a t e d t o be a good e s t i m a t e

o f t h e amount o f c o m p le x ed F e .

92
The DPTA a n d NTA e x t r a c t a b l e A l a r e a l s o c o m p a r a b l e .
H o w e v e r , NTA a n d pPO^ e x t r a c t a b l e A l a r e n o t s i g n i f i c a n t l y
d i f f e r e n t f r o m e a c h o t h e r , w h i l e DPTA e x t r a c t a b l e A l r e s u l t s
a r e s i g n i f i c a n t l y h i g h e r t h a n p y r o p h o s p h a t e a n d EDTA r e s u l t s .
T h e r e f o r e NTA i s

suggested to be a s u ita b le e x tr a c ta n t fo r

A l.
The e x t r a c t i o n o f c a r b o n h a s b e e n m o r e s u c c e s s f u l w i t h
t h e lo w pH s o l u t i o n s .

EDTA a n d NTA e x t r a c t a b l e c a r b o n a r e

s i g n i f i c a n t l y d i f f e r e n t from each o t h e r .

H o w e v e r , EDTA i s

s i g n i f i c a n t l y d i f f e r e n t f r o m t h e o t h e r tw o h i g h pH e x t r a c t ­
a n t s , w h i l e t h e NTA r e s u l t e d i n c o m p a r a b l e a m o u n t s o f e x t r a c t a b l e C w i t h t h e h i g h pH e x t r a c t a n t s .

E ve n t h o u g h EDTA h a s

th e h ig h e st e ffic ie n c y fo r th e e x tra c tio n of carbon,
s u l t e d i n t h e l o w e s t e x t r a c t a b l e Fe and A l.
o v erall s t a t i s t i c a l analysis
NTA s o l u t i o n i s

it

re­

T herefore,

the

s u g g e s t s t h a t t h e lo w pH,

. 1M

th e most s u i t a b l e e x t r a c t a n t f o r Fe, A l,

and C from t h e M ic h ig a n s p o d i c h o r i z o n s .
C hem ical c r i t e r i a
ical c rite rio n

in s o il c l a s s if ic a t io n :

The c hem ­

o f th e % e x t r a c t a b l e Fe and Al o v e r % c l a y ,

fo r th e c la s s if ic a t io n

of Spodosols,

is

suggested to be

low ered to = 0.1 0 to in c lu d e most S p odosols
C rosw ell-G raycalm ,

and M u n i s i n g ) .

It

is

(A uG res-C rosw ell,

a lso suggested th a t

th e r e q u ir e d r a t i o needs t o be low ered t o = 0.0 4 f o r th e
w ell-d rain ed ,
Spodosols

f i n e - t e x t u r e d as w e ll as th e p o o r l y - d r a i n e d

(Onaway a n d K i n r o s s s e r i e s ) .

The d a t a o b t a i n e d i n

93
th is

r e s e a r c h a l s o i n d i c a t e t h a t t h e fo t o t a l c a r b o n , fo

e x t r a c t a b l e F e , a n d fo e x t r a c t a b l e A l o v e r % c l a y , = . 1 2 ,
th e previous c r i t e r i o n f o r c l a s s i f i c a t i o n

of Spodosols,

g i v e s a much b e t t e r e s t i m a t e o f t h e a c t i v e i l l u v i a l m a t e r i a l
of th e spodic B h o riz o n .

Therefore i t

is

suggested t h a t t h i s

r a t i o be used i n p r e f e r e n c e t o th e c u r r e n t l y used r a t i o
fo

e x t r a c t a b l e Fe a n d A l o v e r

fo

clay.

of

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