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Bulletin 342

September, 1932

s

PROFILE CHARACTERISTICS

OF

NEW ENGLAND FOREST SOILS

HERBERT A. LUNT

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CONNECTICUT AGRICULTURAL EXPERIMENT STATION

BOARD OF CONTROL

His Excellency, Governor Wilbur L. Cross, ex-officio, President

Elijah Rogers, Vice-President Southington

George A. Hopson, Secretary Mount Carmel

William L. Slate, Director and Treasurer New Haven

Joseph W. Alsop Avon

Edward C. Schneider Middletown

S. McLean Buckingham Watertown

Charles G. Morris Newtown

STAFF

Administration.

Analytical
Chemistry.

Biochemistry.
Botany.

Entomology.

Forestry.

Plant Breeding.

Soils.

Tobacco Substation
at Windsor.

William L. Slate, B.Sc, Director and Treasurer.
Miss L. M. Brautlecht, Bookkeeper and Librarian.
Miss Dorothy Amrine, B.Litt., Editor.
G. E. Graham, In Charge of Buildings and Grounds.

E. M. Bailey, Ph.D., Chemist in Charge.

C. E. Shepard 1

Owen L. Nolan

Harry J. Fisher, Ph.D. > Assistant Chemists.

W. T. Mathis

David C. Walden, B.S. J

Frank C. Sheldon, Laboratory Assistant.

V. L. Churchill, Sampling Agent.

Mrs. A. B. Vosburgh, Secretary.

H. B. Vickery, Ph.D., Biochemist in Charge.

Lafayette B. Mendel, Ph.D., Research Associate (Yale University)

George W. Pucher, Ph.D., Assistant Biochemist.

G. P. Clinton, Sc.D., Botanist in Charge.

E. M. Stoddard, B.S., Pomologist.

Miss Florence A. McCormick, Ph.D., Pathologist.

A. A. Dunlap, Ph.D., Assistant Mycologist.

A. D. McDonnell, General Assistant.
Mrs. W. W. Kelsey, Secretary.

W. E. Britton, Ph.D., D.Sc, Entomologist in Charge, State
Entomologist.

B. H. Walden, B.Agr. "1
M. P. Zappe, B.S.
Philip Garman, Ph.D.
Roger B. Friend, Ph.D.
Neely Turner, M.A.

John T. Ashworth, Deputy in Charge of Gipsy Moth Control.
R. C. Botsford, Deputy in Charge of Mosquito Elimination.
J. P. Johnson, B.S., Deputy in Charge of Asiatic and Japanese

Beetle Quarantines.
Mrs. Gladys Brooke, B.A., Secretary.

Walter O. Filley, Forester in Charge.

H. W. Hicock, M.F. Assistant Forester.

J. E. Riley, Jr., M.F., In Charge of Blister Rust Control.

Miss Pauline A. Merchant, Secretary.

Donald F. Jones, Sc.D., Geneticist in Charge.
W. Ralph Singleton, Sc.D., Assistant Geneticist.
Lawrence C. Curtis, B.S., Assistant.
Mrs. Catherine R. Miller, M.A., Secretary.

M. F. Morgan, M.S., Agronomist in Charge.
H. G. M. Jacobson, M.S., Assistant Agronomist.
Herbert A. Lunt, Ph.D., Assistant in Forest Soils.
Dwight B. Downs, General Assistant.

Paul J. Anderson, Ph.D., Pathologist in Charge.
T. R. Swanback, M.S., Agronomist. _
O. E. Street, M.S., Plant Physiologist.
Miss Dorothy Lenard, Secretary.

> Assistant Entomologists.

CONTENTS

PAGE

Plan of Investigation 743

Description of the Regions 744

Connecticut 744

New Hampshire 745

Classification of the Profiles 746

Soil and Vegetation of the Localities Sampled 748

Strongly podzolized types, New Hampshire 749

Moderately podzolized, Connecticut 753

Raw humus types, Connecticut 755

Humus types, Connecticut 757

Mild humus types, Connecticut 757

Mull types ' 758

Summary list of profiles 763

Physical Properties 764

Total weight of forest floor 764

Volume weight 766

Color 772

Chemical Properties 774

Methods 774

Presentation of data 774

Biological Studies 797

Nitrogen transformation 797

Organic matter decomposition 815

Distribution of Tree Species and Lesser Vegetation by Profile

Types '. . . 823

Discussion 825

Properties of podzol and mull soils 825

Profile development 826

Relation of forest type and soil properties 828

Summary 829

Plant Species Mentioned 832

Literature Cited 834

PROFILE CHARACTERISTICS OF NEW
ENGLAND FOREST SOILS

Herbert A. Lunt

The study of the soil in the forest is a new phase of American
soil science. To the early colonists and the westward-moving
pioneers who followed, the vast areas of virgin forests were
thought of largely as obstacles to the pursuit of agriculture, and
much excellent timber was destroyed to make room for cultivated
fields. It is natural, therefore, that the soil was first studied from
the standpoint of its utilization in the production of farm crops.

Interest in the perpetuation of our forests was awakened near
the beginning of the present century after it had become clear
that our timber resources were not inexhaustible. As the practice
of forestry developed it was inevitable that such an important
factor as the soil of the forest should be given consideration. The
result has been a demand for knowledge regarding the nature and
properties of the soil in relation to the growth of trees. It is in
response to this demand that investigations of forest soils have
been undertaken in America.

Many years ago much of western Europe had reached the stage
of forest depletion in which New England now finds itself and,
as a result, Europeans have made excellent contributions to the
study of forest soils. We find their work extremely valuable to us,
but also it is imperative that we conduct our own research to deter-
mine how our soils compare with those of Europe before we can
be justified in applying European recommendations to our condi-
tions. The first task confronting the American investigator, then,
is to discover the characteristics and properties of our forest soils
in their natural state. Some of the questions that immediately
present themselves are : In what respect do the several forest soil
types differ from each other? What factor or factors are respon-
sible for the development of these different types ? What part does
the forest and minor vegetation play in the development of the soil
profile ? The objective of this research has been to gather some
factual knowledge relative to the foregoing questions, and others,
particularly as they may apply to Connecticut forests.

PLAN OF INVESTIGATION

The first systematic investigation of forest soils undertaken by
this Station was a study of soil type as a factor in determining the
composition of natural, unmanaged mixed hardwood stands. The
results of this work together with that on a study of the relation

744 Connecticut Experiment Station Bulletin 342

of soil factors to tree growth in red pine plantations appeared in
bulletin form in 1931 (20).

In 1928 investigations were started which had as their objective
the ascertaining of some of the basic properties of forest soils
as found under various stands in different parts of the state. This
bulletin is a progress report on these studies. It deals with some
of the important physical, chemical and biological properties and
relationships, as observed in the field and measured in the labora-
tory, of the soil in various kinds of pure and mixed natural stands
and several pine plantations.

Other studies initiated more recently, which are not published
in this bulletin, include :

1. Effect of litter removal by raking and by burning and the effect of
liming upon the soil and upon the growth of the trees in a red pine plantation.

2. Fertilization of coniferous seedlings in the nursery.

3. Fertilization of young red pine trees (5 to 6 feet tall at the beginning
of the experiment).

4. Moisture distribution and other miscellaneous studies.

DESCRIPTION OF THE REGIONS

New England lies east of the State of New York and north of
Long Island Sound and constitutes the extreme northeastern tip of
the United States. The work reported in this bulletin was carried
on in Connecticut, and in a few localities in New Hampshire — in
the latter instance in cooperation with Northeastern Forest Experi-
ment Station of the United States Forest Service.

Connecticut

Since the geology and the soils of Connecticut have been very
ably described by Morgan (33) it will suffice here to state that
Connecticut is divided into a western highland, a central lowland,
and an eastern highland. Granitic and dioritic gneisses and schists
constitute the bulk of the highland rocks, and red sandstones and
shales that of the central lowland. Massive intrusions of basaltic
trap rock are conspicuous features of the landscape in the central
lowland.

Elevations vary from sea level in the south to a maximum of
2355 feet in the northwest portion. None of the localities in
Connecticut described in this bulletin occur at either extreme.

The climate is characterized by relatively long cold winters and
short rather humid summers. The mean annual temperature is
47-49° F. ; mean maximum in winter 31-38°; mean minimum in
winter 15-20°; length of growing season 150-170 days; mean
annual precipitation 44-46 inches, well distributed throughout the
year.

Description of the Regions 745

The forest vegetation of Connecticut has been classified by Lutz
(28) into the following associations : Red cedar-gray birch associa-
tion 20 per cent (of total forested area) ; hardwood association 70
per cent ; hemlock-hardwood association 5 per cent and swamp
association 5 per cent. He describes the hardwood association as
follows :

"In the hardwood association there is great variation in composition, due
to the large number of tree species in the region. An 'inferior hardwood'
and a 'better hardwood' phase may be recognized ; but these two phases are
merely developmental stages within the larger association. Very often during
the early development of a hardwood association the inferior hardwoods
predominate ; dogwood, hop hornbeam, blue beech, red maple, shad bush,
choke cherry, sassafras, butternut, pignut hickory, bitternut hickory, and
iarge-toothed aspen. In the early developmental stages of this association,
red cedar and gray birch individuals are often present with the inferior
hardwoods, representing relics from a preceding red cedar-gray birch
association. As the hardwood association approaches maturity, the inferior
hardwood species become subordinate and the better hardwoods attain domi-
nance. Such species as the following are considered better hardwoods : red
oak, scarlet oak, white oak, chestnut oak, black oak, white ash, shagbark
hickory, mockernut hickory, black birch, paper birch, yellow birch, beech,
yellow poplar, black cherry, white elm, sugar maple, and basswood. With the
establishment of the better hardwoods, hemlock may begin to appear. This
species presages the successional development of the association toward the
hemlock-hardwood stage Over small areas pure stands of certain hard-
wood species may occur, but as a rule the forest is a mixture. With the loss
of chestnut, due to chestnut blight disease (Endothia parasitica (Murr.)
Ander. and Ander.), the oaks have gained greatly in dominance as compared
with the other hardwood species. In fact, at the present time the oaks as a
group make up a predominant part of the southern New England hardwood

association The density of the undergrowth, and also the composition,

depend largely on the past treatment of the area and to a less extent, on the
character of the soil. The herbaceous vegetation is rich, both in number of
species and of individuals."

The soils are quite sandy or gravelly in texture with fine sandy
loam and loam constituting perhaps the largest percentage. Silt
loams and clays are very limited in extent and are rarely forested.

From the standpoint of soil profile development Connecticut lies
on the border line between the gray brown soils to the south and
west and the strongly podzolized soils to the north. Hence it is of
considerable interest to know the controlling factor or factors that
determine the kind of profile that is formed in this region.

New Hampshire

Lying farther north and generally at a higher elevation New
Hampshire has a climate that is somewhat cooler than that of
Connecticut. The Weather Bureau cites the following data as
applicable to New Hampshire and its neighbor state on the west,
Vermont :

746 Connecticut Experiment Station Bulletin 342

Mean annual temperature 41-42° F. ; mean maximum in winter
25-30° ; mean minimum in winter 4-10° ; length of growing season
120-132 days; mean annual precipitation 44-46 inches, fairly well
distributed throughout the year. Due to the great differences in
elevation — sea level to 6293 feet as the extremes — local climates
vary greatly, and must be taken into consideration in each instance.

Westveld (51) has described the following forest type in the
White Mountains section of the state: (1) spruce-flat, (2) spruce-
hardwoods, (3) spruce-slope, (4) spruce-swamp, and (5) old-
field spruce. "Nearly all the so-called pure spruce stands have an
admixture of hardwood species. Stands containing the highest per-
centage of spruce and fir are usually found in the old-field and
spruce-slope types."

Morgan and Conrey (32) describe the origin of the soils of
a typical area as follows : "The soils of the Cherry Mountain tract
are formed from glacial deposits of crystalline rocks, of which a
gray granite gneiss is the most important. For the most part these
deposits are fairly deep, unstratified glacial drift (till), although
on a considerable portion of Plot 1 a typical 'Kame' occurs."

The samplings at Waterville were taken on similar glacial
deposits. The samples at Keene collected for this study were
obtained under white pine occurring on a level terrace not dissimi-
lar to the terraces of central Connecticut.

CLASSIFICATION OF THE PROFILES

At the beginning of this study the classification of the profiles
was based upon the one used by Hesselman. The inadequacy of
this or any other previously developed system is well discussed
by Romell and Heiberg in a recent paper (38) in which they
present a new classification better adapted to American conditions.
Although Hesselman's classification is more or less adhered to
in this bulletin an effort has been made to apply Romell and
Heiberg's nomenclature whenever practicable.

The groupings we have employed are as follows :

(1) Podzol type (Figure 69) in which a definite leached layer is present,
usually one-half inch or more in thickness. This segregation is made irre-
spective of the condition of the organic horizon, which, however, is usually
of the raw humus type.

(2) Raw humus type (with no gray podzolized layer, or at most with only
a very thin layer) Figure 70. The F layer is frequently rather thin, matted
and woven with mycelial threads. The H layer is usually thick (one-half
inch to several inches), mouse gray or black, felt-like and rather tough. This
probably corresponds to Romell and Heiberg's "Greasy Duff."

Classification of the Profiles

747

(3) Humus type, in which there is a definite humus layer* unincor-
porated with the mineral soil, but which is not felty. The nearest ap-
proach in Romell and Heiberg's classification would probably be fibrous
duff.

(4) Mild humus type, a term not wholly satisfactory but fairly de-
scriptive of the condition. It is characterized by the presence of a rather
rapidly decomposing F layer but no H layer. This type is usually found

Figure 69. Strongly podzolized soil. Profile No. 3. Cherry Mountain,

New Hampshire.

in young pine plantations on the better soils and is not considered by
Romell and Heiberg. They speak of it as "Juncker's poorly humified
type."

(5) Mull type (Figure 71) which includes Romell and Heiberg's
crumb mull and grain mull.

It must be accepted, of course, that these designations are not
sharp and absolute. Many border line conditions are observed that
could be put into either of two types, and some are found that
almost defy classification.

748

Connecticut Experiment Station Bulletin 342

SOIL AND VEGETATION OF THE LOCALITIES SAMPLED

Selection of most of the localities sampled was based upon in-
formation furnished by Henry W. Hicock, Assistant Forester at
this Station. Other areas were found by more or less random
observation in the field. M. Westveld, silviculturist at the North-
eastern Forest Experiment Station, located the areas sampled in
the White Mountains. The accompanying map, Figure 72, shows
the distribution of the localities sampled.

Figure 70. Upper portion of a raw humus profile from a scarlet oak
stand. Profile No. 13. Bethany, Conn.

In all cases samples were collected by horizons from one or
two pits dug in a representative portion of the forest. Identification
of the vegetation was made for the most part by Henry W. Hicock,
M. Westveld, or Henry Bull. In all cases the common name of
the plants has been used in the text. The complete list of tree and
ground vegetation together with their scientific names will be found
just preceding the bibliography, page 832.

In this descriptive material the following abbreviations are used :

M = mycorrhiza

R. D. = root development

c. s.

—

coarse sand

s. 1.

=

sandy loam

f. s. 1.

=

fine sandy loam

1. s.

=

loamy sand

1. f. s.

=

loamy fine sand

Localities Sampled

749

Strongly Podzolized Types, New Hampshire

1. Cherry Mountain Plot 1. Clear cut plot. Elevation range 1973 to
2002 feet. Laboratory Nos. 9 - 16. Sept., 1928.
Soil. Northern counterpart of Hinckley s. 1. Hummocky topo-
graphy; excellent to excessive drainage.
F: 0 - Y> in. Readily decomposing soft and hard wood litter.

Fair R. D. and good M.
H: Yz - 2J4 in. Chocolate brown, powdery, fluffy raw humus,
classified between a root duff and a greasy duff. Good R. D.
but no M observed.

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Figure 71. Mull soil profile exhibiting almost no horizon differentiation.
Simsbury, Conn.

A2: 2Y-2. - 4 in. Light gray, structureless 1. s. Poor R. D.

B^: 4 - 6 in. Very dark brown, dense, compact loam with fair R. D.

B2: 6-9 in. Deep rust brown soft to firm s. 1. Fair R. D.

B3: 9-22 in. Reddish vellow brown, loose and open 1. s. Fair

R. D.
C,: 22-30 in. Yellowish gray sand. Fair R. D.
C2: 30 in. 4-. Gray sand. Some R. D.

750 Connecticut Experiment Station Bulletin 342

Forest cover. Spruce and fir had been cut to about 8 inches d. b. h.
and the hardwoods to 10 - 12 inches d. b. h. At the time of
sampling there were left scattered trees of yellow birch, spruce
6 inches to 30 feet high (although most of the taller ones had
blown down), yellow birch, and balsam fir seedlings.

Ground cover. Hobblebush, striped maple, and red maple seedlings.
Rather sparse herbaceous growth with some moss.

2. Cherry Mountain Plot 2. Spruce-hardwood type Fig. 73. El. 1994-

2014 ft. Nos. 17-24. Sept., 1928.
Soil. Bench type. Similar to Peru loam except for podzoliza-

tion. Slope E. 15 per cent. Slow drainage.
F: 0 - J4 in- Moderately decomposing litter. Fair R. D. and

good M.
H: Y4 - 6 in. Nearly black raw humus of the "greasy duff" type.

Excellent R. D. and good M.
A2: 6-8^2 in. Gray, structureless, soft 1. s. Very little R. D.
Bj: 8^4 - 10 in. Dark brown, moderately compact loam. Fair R. D.
B2:' 10- 14 in. Dark yellow brown, friable f. s. 1. Little R. D.
B3: 14-20 in. Mottled dark brown and gray, firm, s. 1.
C1: 20-26 in. Mottled olive and brown, compact f. s. 1.
C2: 26 in. + . Slightly mottled grayish to olive structureless, firm,

1. s. Practically no R. D.
Forest cover. Balsam fir, red spruce, red maple, mountain maple,

striped maple, yellow birch, fire cherry.
Ground cover. Reproduction of the above species, Clintonia, painted

trillium, Indian cucumber, wood sorrel, Canada Mayflower,

aster, spring woodfern, moss on rotting logs.

3. Cherry Mountain Plot 3. Spruce-hardwoods type. El. 2061-2100 ft.

Nos. 25-31. Sept., 1928.
Soil. Upland till type, probably Hermon f. s. 1. by present U. S.
Soil Survey classification. A hill top with excellent drainage.

F: 0 - 1 in. Loose, slightly matted material undergoing fair de-
composition. Some mycelial growth. Excellent R. D. and M.

H: 1 - 1^4 in. Mellow, slightly granular black raw humus with
excellent R. D. and M.

A2: 1% - ZYz in. Mouse gray, structureless, soft f. s. 1. Good R. D.

Bit 3% -6 in. Dark brown, firm to soft f. s. 1. to loam. Excellent
R. D.

B2: 6-18 in. Reddish yellow brown, soft, mellow f. s. 1. Moderate
R. D.

Cj: 18-25 in. Yellow brown to grayish yellow, structureless,
loose, 1. f. s. Slight R. D.

C2: 25 in. +. Light yellowish gray, structureless, loose 1. s. and
gravel.
Forest cover. Yellow birch, beech, red maple, sugar maple. A ma-
ture stand.
Ground cover. Mountain maple and striped maple, fire cherry, hob-
blebush, red-berried elder, sugar maple, beech, and yellow birch
seedlings. Also spring woodfern, Canada Mayflower, raspberry,
aster, wood sorrel.

4. Waterville, vicinity of Cascade Falls. Spruce-hardwoods tvpe, about

2000 feet. Nos. 185-191. Sept., 1929.
Soil. Similar to Brookfield loamy sand of the Connecticut classifica-
tion except for podzolization. Slope N. E. 30 per cent. Good
drainage.

Localities Sampled

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752

Connecticut Experiment Station Bulletin 342

F: 0 - 1 in. Moderately decomposing litter.

H: 1 - 4 in. Dark brown raw humus.

H: 4-5 in. Black, well decomposed material with good R. D. and

some M.
A2: 5 - 9 in. Gray, structureless, loose 1. s., some R. D.
Bt: 9-10 in. Dark reddish brown (coffee brown) angular slightly

compact s. 1. to loam.
B2: 10-18 in. Dark reddish brown, granular, fairly compact s. 1.

to 1. s. Some R. D.
Q: 18 in. +• Yellowish brown, granular, fairly compact s. 1.
Forest cover. Spruce, fir, hemlock, birch, beech, maple. Advance

reproduction largely red spruce with scattering of fir.
Ground cover. Hobblebush, wood sorrel, Clintonia, club moss, spring

woodfern, and painted trillium.

Figure 73. Spruce-hardwoods type of forest, Cherry Mountain, New
Hampshire. The soil is podzolized. (U. S. Dept. Agric.)

Waterville, vicinity of Greeley Ponds. Spruce slope type. El. about

2300 feet. Nos. 192-197. Sept., 1929.
Soil. A shallow, very variable soil, somewhat similar to the Hins-
dale series of the Connecticut classification, except for degree
of podzolization. E. slope, 20 per cent, granite rock. Excellent
drainage.
Litter — freshly fallen leaves.

F: 0-1J4 in. A somewhat matted raw humus with much mycelia.
Fair R. D. and M.

Localities Sampled 753

H: \y2 -7 in. Very dark brown, greasy duff with excellent R. D.

and considerable M.
H: 7-8 in. Black, smooth muck-like material quite high in

mineral matter.
A2: 8-11 in. Gray to brownish gray, loose, structureless, stony

c. s. Very few roots.
Bj: 11-13 in. Dark reddish brown (coffee brown) granular, fairly

compact, med. to c. s. Fair R. D.
B2: 12 in. +. Reddish j^ellow-brown granular, quite compact med.

to c. s. Few roots.
Extreme stoniness prevented deeper sampling.
Forest cover. Nearly pure stand of mature, virgin red spruce 12-18

inches d. b. h. with small admixture of yellow and paper birch

and red maple. Understory of spruce and fir reproduction.
Ground cover. Hobblebush, some striped maple. Herbaceous: wood

sorrel, gold thread, clintonia.

Moderately Podzolized, Connecticut

6. Bigelow Brook, near Union, Hemlock-Hardwoods. Nos. 44-50.
Soil. Brookfield loam. Fairly level, in a narrow valley bordered by

much higher land. Good drainage.
F: 0 - y2 in. Moderately decomposed leaf litter. Some white

mycelial growth in spots, but no matting. Excellent R. D.

Mycorrhiza.
H: Y2-2Y2. in. Dark chocolate colored, mellow, porous, spongy

pure humus. Not matted. Little or no mycelia. Very well inter-
woven with fibrous roots. Good M. development.
A2: 2^2-3^2 in. Mouse gray leached layer; f. s. 1., firm but not

compact. Roots penetrate but with little branching.
Bt: 3J/2 - 5 in. Brown to reddish yellow brown loam, slightly

compact. Breaks into coarse angular lumps. Poor R. D.
B2: 5-12 in. Reddish yellow brown loam to f. s. 1., less compact

than Bj and more yellow in color. Fairly good R. D.
Q: 12-20 in. Yellow fine s. 1. to loam. Soft, structureless. Fair

R. D.
C2: 20 in. -f-. Not examined but appeared to be fairly typical of

Brookfield loam of a good depth for N. E. Connecticut.
Forest cover. Hemlock 75-100 years old. with black birch, red

maple, sugar maple and white birch. Fairly deep shade.
Ground cover. Very sparse except in openings. Partridgeberry,

whorl pogonia and some hemlock and red maple reproduction

were present in vicinity of pit.

7. Voluntown (7 or 8 miles south of the village) mixed hardwoods.

Nos. 51-59.
Soil. Gloucester s. 1. to f. s. 1. Level, good drainage.

F: 0 - J4 hi. Slightly matted material with but little mycelial
growth. Fair R. D. and M.

H: y^-Xy^'m.. Fairly open material, not felty, with good R. D.
and very good M. Probably a fibrous duff.

A2: \y-2 in. Purplish grav leached laver, 1. s. to sand. Very
little R. D.

Bj: 2 - 4 in. Dark reddish brown, friable f. s. 1. Some R. D.

B2: 4-6 in. Reddish yellow brown, granular, friable f. s. 1. Prac-
tically no R. D. in this horizon or below.

B3: 6-13 in. Yellowish brown, granular f. s. 1.

754 Connecticut Experiment Station Bulletin 342

B4: 13 - 19 in. Grayish yellow brown, granular, firm f. s. 1.
Q: 19-23 in. Yellowish gray, structureless, slightly compact f. s. 1.
C2: 23 in. +• Gray, compact f. s. 1.
Forest cover. Black, scarlet and white oak, red maple, hickory, and
chestnut sprouts. Reproduction of the foregoing and also chest-
nut oak.
Ground cover. Hazelnut, blueberry, shadbush, star flower, winter-
green, and brake fern.

8. Lake Wintergreen, near New Haven, mixed hardwoods Nos. 119-125.
Soil. Wethersfield f. s. 1. Gentle slope N. Fair to good drainage.

F: 0 - Ys in. Slightly matted. Some mycelia.

H: Y% - 1 in. Porous, black, spongy material; a fibrous duff ap-
proaching a greasy duff. Good R. D. and fair M.

A2: 1 - 2 in. Purplish gray s. 1.

Bj: 2 - 4 in. Reddish brown f. s. 1. somewhat compact.

B2: 4-12 in. Light purplish brown f. s. 1. compact.

B3: 12-22 in. Same color but a little coarser and more compact.

Cj." 22 in. +. Brownish purple very compact s. 1. There was some

R. D. in Bj but practically none below that horizon.

Forest cover. Red oak, white oak, chestnut oak, beech, gray birch.

Ground cover. Laurel, huckleberry and low bush blueberry in great

abundance, witch-hazel, male-berry, arrow wood. Red pine and

white pine underplanting.

9. Eastford - Pomfret. Between Phoenixville and Abington on the

Eastford - Pomfret town line. Oak stand. Nos. 180, 370-372,
175. July and Nov., 1929.
Soil. Charlton f. s. 1., but not typical. Gently rolling, good drainage.

Litter: y in. Loose, undecomposed leaves.

H: 0-1^2 in. Raw humus, the upper part of which contains an
admixture of charred organic matter.

Aii \y2 - iy in. Mouse gray f. s. 1.

A2: \y±-2y in. Dark gray leached f. s. 1.

JSt: 2y - Ay2 in. Dark reddish yellow brown f. s. 1.

B2: 4y> - 12 in. Yellowish brown f. s. 1. very granular.

B3: 12-27 in. Light yellowish olive f. s. 1. very granular and lack-
ing coherence.

Q: 27-32 in. Light yellowish olive structureless f. s. 1. It should
be noted that the thickness of the various horizons is very vari-
able in this locality. A very definite "ortstein" was found in
several places at depths of 28 - 34 inches.
Forest cover. Chestnut, scarlet, and black oak. A severe burn oc-
curred in this area in 1926, killing most of the trees. At the
present time the new growth is beginning to add again to the
forest floor.
Ground cover. Mostly blueberry and young oak sprouts.

10. Mohawk Mountain. Mohawk State Forest, Cornwall. Worthington

Lot. Conifer-hardwoods. Nos. 379-385. Nov, 1929.

Soil. Hermon f. s. 1. Topography rolling, surface very rough due to
boulders of granitic gneiss. Detailed information relative to the
several horizons is lacking, although the following horizons were
sampled: Litter, F, H, Bu B2, C1( and C2.

Forest cover. Hemlock, white pine, yellow birch, black birch, red
oak. A fully stocked stand, 150 years old.

Localities Sampled 755

Raw Humus Types, Connecticut

11. Meshomasic Mountain, Meshomasic State Forest, Portland. Oak

forest. Nos. 305-308. Oct., 1929.
Soil. Gloucester f. s. 1. shallow phase. Nearly flat mountain top.
Drainage good. Moderate amount of granitic gneiss rocks and
boulders.

Litter - current leaf fall.

F: 0 - Y/2 in. Matted to fragmentary, slow decomposition. Good
mycelia growth. Fair R. D. and very few M.

H: ^2-3^4 in. Dark brown to black, very fibrous, quite felty,
spongy raw humus. To be classed as fibrous duff. Good to very
good mycelia growth with excellent R. D. Moderate M de-
velopment.

A2: Very thin. Brownish gray leached layer f. s. 1.

Bj: 3^-6^4 in. Reddish yellow brown f. s. 1. Finely granular
structure. Very good R. D. No M.

B2: 6^4 _ ? in. Light yellowish brown f. s. 1., finely granular, firm.
Fair to poor R. D.

Bed rock reached at about 2 feet.
Forest cover. Scarlet oak 98 per cent, occasional white oak. An ex-
tremely open, ragged stand, 80 years, with practically no younger
trees. Formerly much chestnut existed here.
Ground cover. Huckleberry, smilax, brake fern, sheep sorrel, male-
berry, red maple, sassafras, shadbush, high bush blueberry, low
bush blueberry, chokeberry, mosses. Very little oak reproduc-
tion.

12. Mansfield. On Route 109 just East of Houston Nurseries, Oak

forest. Nos. 426 - 432. Sept., 1930.

Soil. Probably Brookfield f. s. 1. Nearly level on top of rounding

hill. Quite stony (gneiss). Excellent drainage.
Litter - current leaf fall.
F: 0 - Yz in. Slightly matted material undergoing decomposition

at a moderate rate. Good development of mycelia and poor R. D.

Very little M.
H: 54-l.x4 in. Dark, moderately raw, somewhat felty. Mycelia,

R. D., and M. well developed.
A2: \% - 4% in. Dull reddish brown, granular, firm f. s. 1. with

good R. D. and M.
Bii 4% - 9% in. Bright reddish brown, with other characteristics

similar to A2. .

B2: 9l/2 - 16^> in. Yellowish red brown, granular, firm f. s. 1.

Fair R. D. and no M.
Ct: 16^4 in. +. Yellowish brown with grayish olive cast. F. s. 1.

single grain structure, firm to slightly loose. R. D. poor.

Forest cover. Black and scarlet oak with some white oak constitut-
ing 98 per cent, about 22 years. Gray birch, large toothed aspen,
mockernut hickory also present.

Ground cover. Low bush blueberry, black cherry, oak and hickory
seedlings, hazelnut, sarsaparilla, huckleberry, shadbush, arrow-
wood, grasses, and mosses.

13. Bethany, on Rainbow Road. Oak stand (Figs. 74 and 70.) Nos.

S358-361. June, 1931.
Soil. Gloucester f. s. 1. Level area on top of hill. Similar in many
respects to the Meshomasic locality with elevation considerably
higher at the latter place. Drainage good.

756

Connecticut Experiment Station Bulletin 342

F: 0-1 in. Matted material containing considerable mycelia.

Fair R. D. and some M.
H: 1 - 2y2 in. Black, felty, raw humus with good R. D. and some

M. A fibrous duff.
A2: Very thin, slightly grayish leached layer. Hardly more than

a trace.
A3: 2^4-5 in. Medium brown with yellowish cast. Granular, firm

f. s. 1.
Bj: 5-10 in. Yellowish brown with slight reddish cast f. s. 1.

Granular, firm. Some rocks.
B2: 10- 17 in. Yellowish brown f. s. 1. Quite rocky.

Figure 74. Slow growing stand of scarlet oak, Bethany, Conn. Profile
No. 13. The soil is a typical raw humus. (Figure 70.)

Forest cover. Scarlet oak and chestnut oak, with some red and black

oak, wild black cherry.
Ground cover. Reproduction of the above species, arrow-wood,

huckleberry, spikenard.

14. Devil's Hop Yard State Park, East Haddam. Hemlock-hardwoods.
Nos. 32 - 37. 1928.

Soil. Brookfield loam to f. s. 1. Nearly level, on a bench considerably
above a stream. Excellent drainage.

Localities Sampled 757

F: 0-^2 in. Normally decomposing mixed hardwood and hem-
lock leaves.

H: Yz- 2>Y2 in. Dense, very dark brown, slightly felty. Consid-
erable mycelia present, but few roots.

At: 2>y2 - 5 in. Brown, light loam, firm.

A2: 5-10 in. Light brown f. s. 1. Mellow.

B±: 10- IS in. Yellowish brown with dull red cast.

B2: 15-21 in. Yellowish brown with bright reddish cast.
Forest cover. Hemlock about 100 years, black birch, aspen, laurel,

witch hazel. Dense shade.
Ground vegetation. Ground pine, rattlesnake plantain, partridge-
berry, Canada mayflower, sweet pepperbush.

Humus Types, Connecticut

15. Maltby Lakes. West of New Haven, red pine plantation of New

Haven Water Co. Nos. 112-118. Aug., 1928.
Soil. Hollis f. s. 1. Nearly level, considerable small stone, good drain-
age.
F: 0 - 3/i in. Rather open needle layer containing considerable

mycelia. Good R. D. and M.
H: % - 1% in. Matted with roots and red moss. A tendency to

become raw humus. Some mycelia present; excellent R. D. and

M. Some evidence of earthworm activity.
At: \y$-\y-i in. Dark gray-brown f. s. 1. Fine crumb structure,

mellow. Good R. D. and M. Some worms.
A2: \y2 -6 in. Brown f. s. 1., same characteristics otherwise.
B: 6 - 22 in. Light to yellowish brown f. s. 1. Single grain, firm.

Very few roots and no M. or earthworms.
d': 22-26 in. Yellowish brown sandy loam.
C2: 26 in. -f. Grayish yellow-brown 1. s., slightly compact.
Forest cover. Pure red pine, 18 years. Site index 18. No ground

cover.

16. Peoples Forest, Barkhamsted. Beech-hemlock stand 100-150 years

old, with a little maple reproduction. Full stand. Nos. 317, 318,
319. Oct., 1929.
Soil. Beckett f. s. 1. Gentle slope. Litter, H and A, sampled.

17. Cockaponset State Forest, Haddam, Beaver meadow district, Com-

partment 7. Hemlock-hardwoods. Nos. 367-369. Nov., 1929.
Soil. Haddam s. 1., on a steep S. W. slope. Considerable gray sand-
stone and granite present. Excellent drainage.
F: 0-1 in. ±. A mixture of hardwood leaves and needles.
H: 1 - 2 in. ±. Black, well decomposed humus, fairly open.
A3: Trace. Dark gray podzolized s. 1.
A3: 2 - 8 in. Reddish brown, loose sand.
B: 8 in. -|-. Brownish red, loose sand.
Forest cover. Hemlock, beech, 70 - 90 years, butternut, black birch,
white oak, mountain laurel, red maple. Ground cover not re-
corded.

Mild Humus Types, Connecticut

18. Rainbow Red pine plantation, Windsor. Block 24. Unthinned. 30

years. Site index about 8. Sept., 1928.

758 Connecticut Experiment Station Bulletin 342

Soil. Merrimac c. s., level terrace, very uniform. Excessive drainage.

F: 0 - Yi in. Slightly matted needle accumulation. Some mycelia
present. Very few M. Fair to good R. D.

Ax: J^-1 in. Brownish gray c. s., single grain loose. Fair R. D.

Aa: 1 -8 in. Grayish brown c. s.

B,: 8-20 in. Yellowish brown with reddish cast, c. s. Poor R. D.

B2: 20-28 in. Yellowish brown, c. s.

Q: 28 in. +. Yellow-gray brown c. s. Some fine gravel present.
Forest cover. Red pine pure stand, planted 1902. No ground cover.

19. Peoples Forest, Barkhamsted. Old field white pine immature. 35

years full stocking. Oct, 1929. Nos. 311, 311J4, 312.
Soil. Merrimac 1. s. nearly level, excellent drainage. F, H and A2
sampled.

20. Cockaponset State Forest, Haddam. Ponsett pine lot. Pine-hard-

woods. Nos. 363 - 366. Nov., 1929.
Soil. Hinsdale f. s. 1. Gentle slope S. W. near summit of hill. Good
drainage. Very little stone.

F: 0 - Y in. ±. Moderately rapid decomposition. Some mycelia.
No R. D. or M.

H: Y - 1 in. ±. Open, rather loose structure with some mycelia.
Good R. D. and M.

A2: Trace. Gray f. s. 1.

A3: % - 7 in. Yellowish brown, mellow f. s. 1.

B: 7 in. +. Reddish yellow-brown f. s. 1.
Forest cover. Old field white pine 35 - 40 years, full stand. Consid-
erable gray birch, some dogwood, red maple and black oak.
Ground cover. Ground pine. This was formerly a cultivated soil.
The pine is becoming stunted. Growth has decreased from ap-
proximately 1^2 feet per year to less than 1 foot during the past

5 or 6 years.

Mull Types

21. Bethlehem, N. H. W. of village 1 mi. El. 1400 feet. Nos. 400 - 403.

June, 1930.
Soil. Loam, not named. Gentle slope W. Fair to good drainage.
Litter - Rapidly decomposing leaves of rather unequal distribution.
Ax: 0 - 7 in. Black, mellow crumb mull, loam. Excellent R. D. but

no M. observed.
B: 7-17 in. Dark yellowish brown, granular, firm, s. 1. to loam.

Good R. D.
d: 17 in. +. Grayish brown, coarsely granular, firm, s. 1. Few
roots.
Forest cover. Beech, yellow birch, sugar maple, 40-80 years; bass-
wood, white ash, spruce, striped maple, American hop hornbeam.
Ground cover. Adders tongue, clintonia, spring woodfern, twisted
stalk, painted trillium, violet, Canada mayflower.

22. Groton, between old Mystic and New London. Mixed hardwoods.

Nos. 60-65, Oct, 1928.
Soil. Gloucester f. s. 1. Nearly level, excellent drainage. Some stone
and gravel. Each annual leaf fall decomposes within the year, so
no accumulation takes place.
Aji 0 - 1 in. Brown with slightly grayish cast. A good earthworm
mull. Crumb structure, mellow. Good R. D. Few M.

Localities Sampled

759

A2: 1 - 7 in. Brown f. s. 1. Crumby and mealy.

B1: 7-13 in. Reddish brown s. 1. Granular and friable. Fair R. D.
No M.

B2: 13 - 19 in. Yellowish brown s. 1.

B3: 19-23 in. Grayish yellow-brown, very f. s. 1. slightly compact.

G: 23 in. +. Yellowish gray to gray very f. s. 1. slightly com-
pact.

Figure 75. Vigorous growing stand of mixed hardwoods. Middlefield,
Conn. Profile No. 23a. The soil is an excellent mull. Compare with
Figure 74.

Forest cover. Red oak, black oak, white oak and hickory 75-100
3rears with understory of sugar maple, blue beech, white ash,
and American hop hornbeam.

Ground cover. Reproduction of forementioned species together with
black cherry, arrow-wood, chestnut, blueberry, huckleberry,
golden rod, spotted wintergreen, greenbrier, aster.

22a. Middlefield. Property of Beseck Fish and Game Club, near Dur-
ham Town Line. Mixed hardwoods, Fig. 75. Nos. S362 - 363.

760 Connecticut Experiment Station Bulletin 342

Soil. Cheshire f. s. 1. to loam. Slope E. 10 per cent. Fair drainage.

The block is subject to some seepage from adjacent higher land.

An excellent mull.
Litter - current year's leaf fall.
At: 0-3 in. Dark brown with reddish cast, mellow f. s. 1. to loam.

Very good R. D. Fair M.
A2: 3 - 8 in. ±. Pale reddish brown to medium brown, mellow

f. s. 1. to loam.
B : 8 - 24 in. ±. Light reddish to yellowish brown coarsely gran-
ular firm to compact f. s. 1.
Forest cover. Red, black, chestnut and white oaks (70 - 80 per cent)

basswood, pignut and bitternut hickories, white ash, beech, sugar

maple, tulip-tree, black birch, sassafras. A high forest with

abundant small trees and large shrubs.
Ground cover. Tall dogwood, arrow-wood, witch-hazel. Asters,

grasses, partridgeberry, several ferns, and a number of small

herbs.
This is an excellent stand containing some fine timber.

23. Middlebury, Whittemore property, red pine plantation. Nos. 76-81.

Oct., 1928.
Soil. Charlton f. s. 1. to loam on a 5 per cent slope E. Some stone.
Drainage moderate to good.

F: 0 - 1 in. Red pine needle litter undergoing moderate decompo-
sition. Fairly open. Considerable mycelia. Very good earth-
worm activity. Fair F. D. and some M.

A1: 1 - 5 in. Very dark brown f. s. 1. to loam. An excellent crumby
mull, very mellow. Good R. D. and M.

A2: 5-8 in. Dark brown mellow mull with good R. D. and M.

Bj: 8-13 in. Reddish yellow-brown, granular, friable. Fair R. D.
Poor M.

B2: 13-17 in. Light reddish yellow-brown, granular but firm.
Poor R. D. and no M.

B3: 17-23 in. Yellowish brown with reddish cast, f. s. 1.

d: 23 -25 inches. Olive gray, heavily mottled with reddish brown.
Firm. Very f. s., micaceous.

C3: 25 in. +. Olive gray, slightly mottled.
Forest cover. Pure red pine, about 19 years. Site index 21. No
ground cover.

This profile is characterized by the exceptionally good mull con-
dition of Ai and A2.

24. Devil's Hop Yard State Park, Haddam. Hemlock. Nos. 38 - 43.

1928.
Soil. Hinckley f. s. 1. on a 50-60 per cent slope E. Small boulders
present and much coarse gravel. Drainage excellent.
F: 0 - J4 in. Rather loose, rapidly decomposing needle and leaf

litter, showing some earthworm activity.
A1: % - 2J4 in. Dark gray brown f. s. 1. An excellent crumb mull,
very mellow. Good R. D. and fair M. Much earthworm activity.
A2: 2y2 - 5 in. Dark brown f. s. 1. Fair crumb mull, mellow. Fair

R. D.
A3: 5-10 in. Light brown with yellowish cast, granular, friable.
B : 10-20 in. Yellowish brown f. s. 1.

Co.: 20 in. +. Bright yellowish brown sandy and gravelly loam.
Forest cover. Hemlock 75 - 100 years. Reproduction of sugar maple.
Ground cover. A sparse covering of ferns and some partridgeberry.

Localities Sampled 761

25. South Coventry, Pine Lake Shores, real estate development, Coven-

try. Red pine. Nos. 373-376. Nov., 1929.
Soil. Hinsdale f. s. 1. on the lower end of a long rather steep slope.

Excellent drainage. The forest floor was an average plantation

accumulation undergoing moderately rapid decomposition.
F, Au B„ and B2 sampled.
Forest cover. Red pine 18 years old making exceptionally rapid

growth. Site index 22, which is the highest recorded in the

state (20, p. 745).
Ground cover. None.

26. West Hartford. Hartford Water Board land; near block No. 42.

Mixed hardwoods. Nos. 178, 179. Aug., 1929.

Soil. Holyoke f. s. 1. to loam on gentle slope. Good drainage. Lit-
ter and Aj sampled. An excellent mull.

Forest cover. Red oak, sugar maple, white ash, white oak, bitternut
hickory.

Ground cover. Reproduction of the above; dogwood, hobblebush.

27. Farmington, about 2.5 miles N. of the village. Mixed hardwoods.

Nos. 377, 378. Nov., 1929.
Soil. Holyoke f. s. 1. to loam, very similar to profile 26. A very good

mull. Litter and Aj sampled.
Forest cover. High forest of red, black and white oaks, sugar maple.

Some white ash, pignut hickory, black birch, shagbark hickory

and American bop hornbeam.
Ground cover. Dogwood, arrow-wood, Christmas fern, grape fern,

aster, bittersweet, grasses, woodbine, and many herbs.

28. Middletown - Middlefield. Mr. Comp's property near the town line.

Oak. Nos. 309, 310. Oct., 1929.
Soil. Cheshire f. s. 1. Nearly level upland. Good drainage. An ex-
cellent mull. Litter and Aj sampled.

Forest cover. White oak 90 per cent, black oak, shagbark hickory,

sugar maple.
Ground cover. Seedings of the above, dogwood, huckleberry, high

bush blueberry, low bush blueberry, sassafras, toothed viburnum,

grasses, small herbs and some ferns.

29. Peoples Forest, Barkhamsted, North of Whittemore camp ground.

Young hardwood stand of mixed oaks 30 - 35 years. Full stand.
Nos. 313, 314. Oct., 1929.

Soil. Merrimac 1. s. Litter and A± sampled.

30. Peoples Forest, Barkhamsted. Pure beech stand, 100-150 years,

full stand. Nos. 315, 316. Oct., 1929.
Soil. Litchfield f. s. 1. on a nearly level portion of a long slope. Lit-
ter and A, sampled.

31. Eastford, 0.6 mile west of Phoenixville on road to Mansfield. Oak

stand. Nos. 419-425. Aug., 1930.
Soil. Hinsdale f. s. 1. Upland, 8 per cent slope S.
F: 0 - % in. Flaky, fragmentary material.
H : %. - y2 in. Very thin and not uniformly present. Crumby,

black fine grained material with very good root development.

Few M.

762 Connecticut Experiment Station Bulletin 342

Ai'. */> - 1*A in. Very dark to blackish brown mellow f. s. 1. with
good R. D.

A2: 1^2 - 5J/2 in. Brown with reddish yellow cast, f. s. 1., mealy and
mellow with very good R. D.

B: Sy2 in. + . Yellowish brown with slight reddish cast, finely
granular friable f. s. 1.

This soil is not a true mull, but it scarcely fits into any other
classification.
Forest cover. White, red, black and scarlet oaks 40 years. Occa-
sional hickory.

Ground cover. Witch-hazel, oak seedlings, arrow-wood, dogwood,
wintergreen, partridgeberry, dewberry, low bush blueberry, red
maple, grasses, mosses, some herbs.

In addition to the foregoing profiles, some additional ones
were sampled for volume weight and associated determina-
tions. These are briefly described as follows (the sampling
depths of the various horizons are given in Table 3) :

32. Waterville, N. H., between Mad River Farm and Waterville. White

birch, yellow birch and sugar maple with an understory of
spruce. A strongly podzolized profile overlaid by a six inch
greasy duff layer. B2 very compact; d firm to compact; C2 firm
c. s. with some fine gravel.

33. Keene, N. H. Five Mile Drive. El. about 530 ft. White pine stand

probably 100 years old with some hemlock and maple. This is a
well developed podzol profile in sandy terrace material similar
to the Merrimac sand at Rainbow, Conn., though not as coarse.
Ortstein occurs at a depth of 15-18 in. Q is very compact.

34. Keene, N. H. Another part of the same stand described in No. 33.

The leached layer is 6 in. thick instead of 3 in. and no "ortstein"
was encountered to the depth of the excavation (17 in.) although
the B2, 10- 17 in., was very compact.

35. Norfolk, on Windrow Road, a short distance east of Toby Pond.

On the edge of a terrace. Merrimac f. s. Sampled at a road cut.
A most unusual condition as will be seen by the following de-
scription:

Aja: 0-5 in. Dark brown, f. s., crumb structure.

Axb: 5-10 in. Medium brown, f. s., fine crumb.

A2: 10- 17 in. Grayish white structureless leached 1. s.

B: 17-33 in. Reddish yellow, somewhat compact 1. s.

Q: 33 in. -)-. Brownish yellow sand.

Grass is the only cover.

The above measurements are subject to great variation, the A2, for
example, varying from 0 to 12 in. in thickness, while the over-
laying brown Aj is between 5 and 17 in. thick. According to
Professor R. F. Flint of the Department of Geology, Yale Uni-
versity, there is no evidence that the brown surface soil was
deposited mechanically upon the leached layer.

36. Norfolk. Sample taken on opposite side of the road from No. 35.

A scrubby growth of gray birch and some smaller shrubs re-
sulted in the At being a fairly good mull. Here it was only 5 in.
thick, with the leached A2 only 4 to 5 in.

Localities Sampled 763

37. Windsor Locks, Conn., on road to East Granby. Hardwood stand

of white oak, red oak, maple, ash, cherry. Ground cover of oak,
maple and chestnut reproduction, huckleberry, vaccinium, hazel-
nut, ferns, wintergreen. The soil is Merrimac sand similar to
Profile 18 except that the forest has brought about a greater
modification of the upper layers. There is a definite H layer,
overlaying a slight podzolization. The former agricultural A
horizon is thinner, somewhat lighter in color and shows a defi-
nite trend away from an agricultural soil profile. The F is *4 in.
in thickness, H 24 m-, A2 (leached) trace to % hi-, and A3 5 to 6
in.

38. Lake Wintergreen. Hardwoods, mull, located further up the slope

than No. 8. Younger trees and a larger percentage of gray birch
present. Otherwise similar to No. 8.

39. Lake Wintergreen. Red pine plantation, 18 years. Not very distant

from the previous locality. A mull type.

40. West River. Porter Hill Road, Bethany. Red pine plantation.

Brookfield f. s. 1. A mull.

41. Lake Chamberlain, Bethany. Red pine plantation. Hollis f. s. 1.

to loam. A mull.

42. Middlebury. Whittemore property, opposite big bend in road.

Red pine plantation. Charlton v. f. s. 1. to loam. A mull type.

43. Middlebury pasture. Across road from No. 36. Similar soil but in

pasture instead of forest.

44. Salisbury, East side of Miles Mountain between the summit and

the Housatonic River. Pasture land. Probably Dover f. s. 1.

Summary List of Profiles

Strongly Podzolized, New Hamp- Mild Humus Types, Connecticut
shire 18. Rainbow

1. Cherry Mountain, Plot 1 19. Peoples Forest

2. Cherry Mountain, Plot 2 20. Cockaponset State Forest

3. Cherry Mountain, Plot 3

4. Waterville, Cascade Falls M"H Types

5. Waterville, Greeley Ponds 21- Bethlehem, New Hampshire

. 22. Groton, Connecticut

Moderately Podzolized, Connecticut 22a. Middlefield

6. Bigelow Brook 23. ' Middlebury

7. Voluntown 24. Devil's Hop Yard
b. Lake W intergreen 25. South Coventrv
9. Eastford - Pomfret 26. West Hartford"

10. Mohawk Mountain 27. Farmington

Raw Humus Tvpes, Connecticut 28- Middletown - Middlefield

11. Meshomasic Mountain 29- Peoples Forest

12. Mansfield 30- Peoples Forest

13. Bethany 31. Eastford

14. Devil's Hop Yard u,v i r> ci

Additional Profiles

Humus Types, Connecticut 32. Waterville, New Hampshire,

15. Maltby Lakes Podzol

16. Peoples Forest 33. Keene, Podzol

17. Cockaponset State Forest 34. Keene, Podzol

764

Connecticut Experiment Station Bulletin 342

35. Norfolk, Connecticut, Podzol

36. Norfolk, Podzol

37. Windsor Locks, Podzol

38. Lake Wintergreen, Mull

39. Lake Wintergreen, Mull

40. West River, Mull

41. Lake Chamberlain, Mull

42. Middlebury, Mull

43. Middlebury, Pasture

44. Salisbury, Pasture

PHYSICAL PROPERTIES

Total Weight of Forest Floor

One outstanding characteristic of forest soil, particularly in the
northern forests, is the layer of organic debris upon its surface.
Measurements of the amount of this material on the ground were
made in a number of stands. The procedure was to collect carefully
all of the debris in one square foot, using a hollow iron square of
this dimension. The material was then dried, weighed and the
amount calculated to an acre basis. From two to four samplings
were made of each profile. Since thickness was noted also, it was
possible to calculate the approximate weight per acre inch. These
results are shown in Table 1.

Table 1. Weight of Forest Floor
Pounds per acre

Forest type

F layer

H layer

Profile

<D

Per

a;

Per

type

"^ OJ

Total

acre

M V

Total

acre

o •

u O

•° %

inch

'£ a

inch

P4 2;

H.S

H-h

New Hampshire

Podzol types

White pine

33

134

42981

24560

VA

75697

50464

White pine

34

H

21107

28142

14

46531

37224

Spruce-hdws.

32

—

—

534

263547

43924

Spruce-hdws.

32a1

34

15350

20466

2/2

95460

38184

Connecticut

Podzol types

Hardwoods

8

54

10361

16576

34

45860

61148

Hardwoods

9

—

—

134

88553

50600

Hardwoods

37

y2

12760

25520

34

80781

107708

Humus types

Hardwoods

13

%

11800

13500

IVz

53726

35818

Red pine

18

m

42981

22920

—

—

Mull types

Hardwoods

38

V*

7579

20208

—

—

. — .

Red pine

39

4

7942

31768

—

—

—

Red pine

40

34

7051

9400

—

—

—

Red pine

41

1/2

13824

9216

—

—

—

Red pine

42

1

14928

14928

—

—

—

Average

19767

53133

132a. Check plot in a girdling experiment near Waterville, N. H. Not previously described.

Physical Properties

765

Measurements made in 1929 on the Station's plantation at Rain-
bow are given in Table 2.

Table 2. Weight of Forest Floor in Coniferous Plantations

Red pine 27 years old,

thickness of duff,

yi - lyi inches

Pounds per acre

White pine 27 years old,
thickness of duff,

J4-1 inch
Pounds per acre

1

21024

2

21024

3

32736

4

25920

5

32064

6

34176

Plot

7

26400

8

16800

9

15072

10

30240

11

15648

12

25344

Average 27920

Average 21590

This table shows that for the same age of trees, the accumula-
tion under red pine is greater than under white pine.

Considering the data in both tables, it is evident that even in
Connecticut forests there is a rather large accumulation of the
F portion of the duff and, where it occurs, a large amount of the
more decomposed H material, equal in many cases to that found
in the more strongly podzolized white pine region of Keene and
the spruce-hardwood region of the White Mountains of New
Hampshire. The total amount of duff is always greater in the
podzol or raw humus types than in the case of mull or mild humus.

While the total amount of H material found under the northern
spruce and spruce-hardwood forests may vary tremendously, yet
the variation in weight per acre inch is much narrower. Apparently
an increase in thickness does not result in a corresponding increase
in compactness.

Taking all the facts into consideration, we may assume the
following weights per acre inch of duff as being approximately
correct for the types given :

Northern forests with strongly

podzolized soils
Connecticut mild podzol
Connecticut mull

Weight per acre inch
F H

20,000 pounds 40,000 pounds
15,000 pounds 40,000 pounds
15,000 pounds —

These figures have been used in this bulletin in calculating the
weight of duff of those profiles whose thickness, but not weight,
was taken at the time of sampling.

In studies carried on by Alway and Harmer (2) on forest floor
material from three different localities in Minnesota, they found
amounts varying from 25,000 to 56,000 pounds under virgin or

766 Connecticut Experiment Station Bulletin 342

nearly virgin maple-basswood-oak type, and 47,000 to 193,000
under spruce-balsam-birch type, with an average of 42,108 pounds
in the first instance and 100,188 pounds in the second.

Auten's (4) observations in the Mont Alto State Forest of
Pennsylvania reveal values ranging from 23,000 to 121,000 pounds
per acre. In every case a slope had more duff than a ridge, and a
valley more than a slope.

Henry (18) gives the following figures as the average total air
dry weight of the forest floor under three forest types : Beech,
9297 pounds per acre ; spruce 12,369 pounds ; and Scotch pine,
16,317 pounds. These values found under Central European condi-
tions are not greatly dissimilar to the results of measurements
made in Southern New England, but are considerably lower than
the values found in the more northern forests, as would be
expected.

Volume Weight

In order to make comparisons on an acre basis it is necessary
to know the density or volume weight of each soil horizon. The
commonly accepted value of 2,000,000 pounds of soil for the sur-
face 62/z or 7 inches, and 4,000,000 pounds for the 7 to 20 inch
depth for arable soils, is wholly inadequate in the forest. Harland
and Smith (16) have shown variations of approximately 1,800,000
to 2,400,000 pounds per acre for the upper 6% inches, even in
agricultural soils.

In the present work profiles typical of various conditions were
selected and density determinations were made by the methods
described below. Because of the stoniness of the soil, the presence
of tree roots, and the relative thinness of some of the forest soil
horizons, only two of the several methods (11, 16) that have been
used by other investigators to study soil in place were considered
practical for our conditions. These methods were (a) the tube or
cylinder1 method as recommended by Burger (7) and Craib (10)
in which a steel cylinder 10 cm long and having a capacity of
1000 cc. is driven into the soil and the contents weighed after
drying; and (b) the paraffine-immersion method as described by
Shaw (40).

In some cases both methods were used, in others only the one
more suitable. The paraffine-immersion method was very satisfac-
tory for horizons less than 4 inches in thickness, provided the soil
was moist enough to prevent crumbling. Correction was made for
the weight and volume of stones present that were larger than one-
quarter inch.

iThe writer is indebted to the late Prof. J. W. Tourney of the Yale School of Forestry
for loaning cylinders for this work.

Physical Properties 767

In addition to density, the following related soil properties were
determined on these samples: Moisture equivalent (48), loss on
ignition, organic carbon by the Parr method (3, 6), clay and silt
plus clay, by the hydrometer method (5), and several size fractions
of sands obtained by sieving the material remaining after determin-
ing the silt plus clay. The results are to be found in Table 3.

Segregation of the profiles in the table was based upon the type
of A horizon rather than upon soil series as would normally be true
of non-forested soils. In forest soils the A and upper B horizons
are of considerably more importance than the remainder of the
profile due to the greater role these horizons play in the nutrition
of the forest, and due also to the fact that these horizons are greatly
affected morphologically by the forest and its environment.

In studying the volume weight values in this table it will aid one
who is accustomed to thinking in terms of 2,000,000 pounds of soil
per acre 6^3 inches, to keep in mind that a density of 1.0 means
1,510,835 pounds per acre. Two million pounds per acre mean a
density of 1.324. It is well to note the following points :

a. The low volume weights of the A horizon of the mull types, particularly
in contrast to those of the two pasture soils included.

b. The lower volume weight of the zone of accumulation, Bj, and to a
lesser extent B2 in the podsols.

c. The high volume weight of the "ortstein" samples. (See end of table).

These results are in agreement with those of Burger (7) and
Simpson (41). They sampled by arbitrary depths only, hence
only their upper sample, 0-10 cm, can be compared with the
writer's results.

V

olume Weight of Soil

(0-

10 cm)

(Burger)

(Simpson)

Unmanured meadow

1.034

Denuded site

1.186

Field soil

1.326

Forest site

0.952

Cutting

1.071

50 - 60 year conifers

0.796

100 year hardwoods

0.855

By referring to Figures 76 and 77 one observes the relationships
between several other physical properties and volume weight.
Neither clay alone nor silt and clay are correlated to any definite
degree, and therefore these values were not plotted. On the other
hand organic carbon, loss on ignition, and moisture equivalent all
show a very good correlation. When the data are treated statistic-
ally, the correlation is — .800 ± .033 for carbon and — .511 ±
.0678 for moisture equivalent. Thus it is the organic rather than
the inorganic colloids that control the density of these soils.

768

Connecticut Experiment Station Bulletin 342

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Connecticut Experiment Station Bulletin 342

t

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•

X

• LOSS ON IGNITION
XCARBON

k

-6-

O

■* e

O 6

■

X

f>

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-1 1 1 1

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3

2 <->

.7 .8 .9 1.0 I.
VOLUME WEIGHT

1.2 1.3
{.WATER -•

Figure 76. Relation between loss on ignition, organic carbon and volume
weight. (Each point is a group average.)

To present the density of forest soils a little more concretely,
Table 4 gives the total weight per acre of the several horizons
making up some typical profiles.

The value of the foregoing data will be more apparent in another
part of the bulletin where the chemical data are presented.

Color

Included in Table 3 are the colors of the various soils collected.
All color observations were made on air dry soil in the laboratory

Table 4. Total Weight per Acre of Some Typical Forest Soil Profiles
to a Depth of 24 Inches

Strong Podzol

Moderate Podzol

Mull

Profile No. 2

Profile No. 6

Profile No. 23

Horizon

Thickness

Thickness

Thickness

inches

pounds

inches

pounds

inches

pounds

F

3/4

15,000

y2

7,500

1

15,000

H

5Va

210,000

2

80,000

—

A,

—

—

4

724,800

A2

2y2

707,800

1

260,500

3

679,500

B,

iy2

305,800

1^

322,800

4

1,177,900

B2

4

996,600

7

1,585,600

5

1,585,600

B3

6

1,766,800

8

2,718,100

6

1,970,700

c3

4

1,359,100

4

1,359,100

1

339,800

Total

5,361,100

6,333,600

6,493,300

Physical Properties

773

under natural daylight from a north window. Most of the samples,
particularly the browns and yellows, were compared directly with
a set of standard samples that Morgan had previously collected
and analyzed for color by the Munsell color disk method (33).
Others were compared with a portion of a set of standard soils
furnished by the Bureau of Chemistry and Soils, Washington.

20

O

ly 10

I

s*

5

.8

1. 7 1.8

.9 1.0 U f.2 13 1.4 1.5 1.6
VOLUME WEIGHT (WATER = /)

Figure 77. Correlation of moisture equivalent and volume weight.

The remaining samples, which differed from any of the soils in
either set of standards, were analyzed for color by the writer with
results given in Table 5.

Table 5. Color Analysis of Certain Soils Found in New England

Yellow

Black

Descriptive term

White
(Neutral 9)

(Yellow
8/8)

Red
(Red 4/9)

(Neutral
1)

Light gray

34

7

10

49

Brownish purple

20

10

42

28

Light yellowish olive

15

33

6

46

Brownish yellow

2

16

23

59

Reddish yellow brown

2

12

20

66

Very dark reddish yellow

1.5

9

11

78.5

Very dark reddish brown

5

7

10

78

(coffee brown)

Do

2

5

7

86

Very dark brown with

5

7

8

80

reddish cast

Very dark brown

5

6

5

86

Grayish black

5

3

3

89

Black

0

2

2

96

774 Connecticut Experiment Station Bulletin 342

CHEMICAL PROPERTIES

Methods

All total analyses were made on 100 mesh air dry soil, while
unground soil passed through a two-millimeter sieve was used
for the determination of pH and the elements in the exchangeable
or water soluble form. Acid soluble iron, R2O3 (oxides of Fe,
Al, P, Mn), and calcium were obtained by digestion of the soil
in HC1, sp. gr. 1.115 on a steam bath for 10 hours. Separation
was made by a modification of several published methods (14,
39, 42). The iron in an aliquot portion was reduced to the ferrous
condition by stannous chloride and then oxidized by a standard
solution of potassium dichromate. The R2O3 constituents were
precipitated and weighed as the hydroxide by the usual methods.

Reaction was determined with the quinhydrone electrode, and
often checked by the Lamotte-Morgan colorimetric test. Nitrogen
and calcium were run by the usual methods ; organic carbon was
determined by means of the Parr apparatus (3, 6). Exchangeable
calcium and magnesium were obtained by leaching the soil with
normal ammonium acetate solution, and exchangeable potassium
by leaching with 0.5 normal acetic acid. Truog's magnesium nitrate
method was used for total phosphorus, while soluble phosphorus
was determined by a modification of Truog's method in which the
soil was treated with 0.004N H2SO4 (47). Exchangeable hydrogen
and total adsorptive capacity were estimated by the method of
Pierre and Scarseth (37).

Presentation of Data
Reaction

One of the outstanding characteristics of a northern forest soil
is the high acidity of its upper horizons, particularly the H layer.
Generally speaking, the thicker the humus and the more nearly
it approaches the raw or greasy state, the greater its acidity. Stated
in another way, such a state is indicative of maximum unsaturation,
the bases being replaced by hydrogen.

The reaction of the soils investigated is given in Table 6. It will
be observed that the pH of the Q layers varies but relatively little
in the different profiles. The relatively low pH of the podzol En
horizon is quite noticeable. In practically all of the profiles re-
ported by Tamm (45) the pH of the Bi layer is greater than that
of the A2.

Hesselman (19) found the raw humus types to be more acid as
a rule than the better humus and mull types. After discussing the
pH values found in different forest types he says, "While it is

Chemical Properties

775

important to know the reaction of forest soil, yet by no means is
that the controlling factor. Mull and raw humus may be of the
same pH and a good, highly productive beech forest soil can be
decidedly acid (pH about 4). Such acidity is no hindrance there-
fore to good production or a favorable soil condition, but on the
contrary it is characteristic of very highly productive soils. A
change in acidity in an alkaline direction is generally favorable,
however, since a marked acid reaction, as has been observed, is
detrimental, not in itself, but in conjunction with other factors."

Table 6. Reaction Expressed as pH

Strong podzol type

Moderate podzol type

1

2

3

4

5

Ave.

6

7

8

9

10

Ave.

Litter

.

4.2

3.9

4.4

4.2

F

5.7

4.7

5.4

4.5

3.9

4.8

4.7

4.3

4.4

—

4.6

4.5

H

3.7

4.4

5.8

3.3

3.8

4.2

3.9

3.9

3.7

4.6

3.9

4.0

A2

3.8

5.8

5.0

3.7

3.7

4.4

3.5

4.0

3.8

—

—

3.8

Bx

4.0

4.0

4.0

3.7

3.8

3.9

4.2

4.5

4.2

4.5

4.0

4.3

B2

4.5

4.8

4.8

4.3

4.3

4.5

4.6

5.1

4.3

4.7

4.5

4.6

B3

4.8

5.7

—

—

—

5.3

—

4.7

4.4

—

—

4.6

Q

5.0

5.8

6.7

4.3

—

5.5

5.1

5.1

4.8

5.3

5.3

5.1

c2

5.1

6.0

6.7

—

—

5.9

5.5

5.3

—

—

5.5

5.4

Raw humus type

Humus type

Mild humus type

11

12

13

14

IS

16

17

Ave.

18

19

20

Ave.

Litter

4.0

4.4

4.7

4.4

_

F

4.0

4.7

4.6

4.3

4.5

—

4.3

4.4

4.7

4.4

4.9

4.7

H

3.5

4.4

4.1

3.9

4.2

4.2

4.0

4.0

—

3.8

4.5

4.2

A,

—

—

—

4.1

4.2

—

—

4.2

4.6

—

—

—

A2

—

4.8

4.4

4.3

4.3

4.8

4.4

4.5

4.9

4.3

5.0

4.7

Bx

4.4

4.9

—

4.6

—

—

—

4.6

4.8

—

—

_

B2

—

4.8

—

4.6

5.0

—

—

4.8

5.4

—

5.0

5.2

Q

—

5.2

—

—

5.2

—

—

5.2

5.5

—

—

—

c2

—

—

—

—

S.2

—

—

—

—

—

—

—

Mull type

21

22

22a

23

24

25

26

27

28

29

30

31

Ave.

Litter

4.8

4.4

4.3

4.4

4.6

5.1

4.6

4.6

F

—

—

4.8

5.5

5.3

4.9

5.3

5.2

Ax

4.5

4.6

5.1

4.9

5.5

5.0

3.9

5.2

4.8

4.6

4.7

5.6

4.9

A2

—

4.7

—

5.1

5.6

—

—

—

—

—

—

5.2

5.2

Bx

—

4.8

—

5.2

—

5.3

—

—

—

—

—

5.6

5.2

B2

5.3

4.9

—

6.0

5.5

5.7

5.5

5.5

B3

—

5.0

—

5.6

—

—

—

—

—

—

—

—

5.3

Cx

5.3

4.9

—

5.8

5.6

5.9

5.5

c2

—

—

—

b.O

—

—

—

—

—

—

—

—

—

Romell and Heiberg (38) found a rather wide range of pH
values in the various humus classes, but the greasy and fibrous
duffs were all more acid than 5.5 and their twin and crumb mulls

776 Connecticut Experiment Station Bulletin 342

less acid than 4.1. The average pH values for Danish heath podzol
soils, according to Weis (50) are as follows:

Raw humus

3.6

(3.5—3.6)

Bleached sand

3.9

(3.7—4.5)

Humus hardpan

4.1

(3.9—4.3)

Iron hardpan

4.5

(4.0—4.7)

Subsoil

4.8

(4.4—5.9)

The relatively small variation in this group of 12 profiles studied
by Weis was due to the fact that all were located adjacent to
one another where the land was level and quite uniform.

Iron, R203, and Insoluble Matter

No analysis of forest soils is more interesting than that show-
ing the vertical distribution of iron, RaOa and insoluble matter
(Table 7). The data on several of these profiles are shown
graphically in Figure 78. Note the definite accumulation of iron
in the B horizon of the podzols, with B2 possessing a higher
percentage than Bi. Even in the mull types a slight accumulation
is apparent.

The insoluble matter generally decreases with the increase in
iron content. In the case of the mull types, on the other hand, the
insoluble matter increases with depth regardless of iron content.

These data furnish the laboratory sanction for the horizonal
designation given to the soils in the field — the B layer being the
zone of accumulation. This point will be brought out further on
in connection with the carbon data.

An interesting comparison may be made with some data obtained
by Tamm (43). An average of five or six of his profiles (profiles
Nos. 1, 2, 3, 4, 12 and 13) is as follows:

FeO

Al ,0,

"Humus"

a 3

2 3

(loss on ignition)

A2

• 1.8

9.8

2.19

B

4.0

12.0

2.32

C

3.2

12.0

0.56

All these profiles are quite strongly podzolized, the B horizon
being either "orstein" or "orterde." Note that the iron content of
the C horizon is higher proportionally in relation to B than are
the strongly podzolized soils in New England (profiles 1, 2, 3).
The same may be said for ALOs It will be observed also that the
humus content of the A2 in relation to that of the B is higher in
the Swedish soils than it is in our New England podzolized soils.

All of Tamm's soils considered above are what he calls iron
podzols. The A2 of his humus podzols (45) is much higher in
humus — seven profiles (Nos. 6, 7, 8, 9, 10, 11, 12) averaging 6.70
per cent, B horizon 6.28 per cent, and C horizon 0.90 per cent
(data on B and C given on first three profiles only).

Chemical Properties

777

PER CENT SESQUIOXIDES

f«,o.

mmm oxides other than Fet o3

0 5 10 15

PROFILE I PODZOL

PROFILE 6 PODZOL

PROFILE 8 PODZOL

PROFILE 14 RAW HUMUS

PROFILE 2 2 MULL

PROFILE 2 3 MULL

Figure 78. Vertical distribution of sesquioxides in six typical profiles.
(Table 7.)

In this connection Jenny (23) studying alpine soils reports the
following analyses.

Iron podzol

Humus

podzol

Fe203

Humus

Fe2°3

Humus

+ A1203

+ A1203

A2

3.99

2.87

1.79

4.61

B

17.00

3.51

4.56

11.22

C

9.70

2.68

2.91

6.12

778

Connecticut Experiment Station Bulletin 342

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Chemical Properties 779

He makes this statement : "Typical of the iron podzol is the
great accumulation of iron compounds in the B-horizon, which
gives to the profile the distinct redbrown color. The main feature
of the humus podzol is the extreme humus accumulation in the
B-horizon, giving it a chocolate color." Jenny refers to Frosterus'
statement that iron podzols contain less than 3 per cent humus
in the B horizon.

It would appear, therefore, that the strongly podzolized soils
of New England would be classified as iron-humus profiles, for
both iron and organic matter are quite low in A2 and high in B.

A profile of considerable interest has been reported from South
Africa. The Frenchhock profile in Western Province (12) was
taken in a valley surrounded by high mountains. The rainfall is
about 40 inches. The soil that now supports a luxuriant vegetation
was formerly covered with a poplar forest, which had been cut
before sampling. The soil, formed from sandstone, "is deep, has
lain undisturbed for a very long period and has a hard iron-humus
pan a few inches below the surface." A portion of the data is
as follows :

Loss on Fe203 Fe203 Fe.,0., pH

Ignition +A1203 +A12°3

A 4.25 3.35 1.328 .42 5.3

B, 6.45 12.25 6.540 .73 4.71

B2 7.45 5.75 1.991 .34 5.16

C 4.15 5.50 1.896 .34 4.81

This profile is interesting in that the greatest concentration of
organic matter is in the B2, but iron and aluminum are concentrated
in Bi. Since loss on ignition was used as a measure of organic
matter these results may be due to a hydration of the colloids.
The fact that the water table fluctuates considerably but seldom
falls more than a few feet below the surface may help to explain
the condition found by analyses. If the iron and aluminum were
equal to or greater in concentration in the B2 than in Bi, this
profile would compare very favorably with New England podzol
soils.

Forest profiles XV, XVI, and XVII reported by C. F. A. Tuxen
in Miiller's "Natiirliche Humusformen" (34) compare in both
humus and iron oxide with the distribution found in New England
soils.

The virgin Culluna-heath soils investigated by Weis (50)
are very interesting in several ways, but particularly so from the

780

Connecticut Experiment Station Bulletin 342

standpoint of iron and humus distribution. The average of 10
profiles is as follows:

Thickness

Fe203

A1203

"Humus"

cm

%

%

%

Aj Raw humus

8.9

0.11

0.12

27.03

Transition zone

3.8

—

—

—

A2 Pure bleached sand

7.0

0.04

0.03

1.79

A3 Humus hardpan

7.4

0.57

0.96

12.65

Bj Iron hardpan

6.2

0.95

0.59

2.65

B2 Transition zone

34.4

—

—

—

Q Subsoil begins at 67.8 cm

0.17

0.17

0.24

Here we see a very distinct differentiation between the ac-
cumulation of the humus and that of the iron. This may be called
an iron-humus podzol with the bulk of the iron occurring separate-
ly and below the bulk of the humus. As has been previously
mentioned, many of the forest soils lying in the podzol zone of
Europe are either humus podzols or iron podzols. Those in this
country appear to be iron-humus podzols, but the iron and humus
are not so distinctly segregated as in the case of the heath soils
investigated by Weis.

Nitrogen

The data for total nitrogen are given in Table 8. In the podzols
we find, in agreement with Edington and Adams (13) the duff
proportionately high in nitrogen, A2 very low, a decided rise again
in B, and C as low or lower than A2. Considering the averages
of the several types we find the nitrogen content of the duff to
be highest in the strongly podzolized types and decreasing through
the humus to the mull types. In every case it is higher in the F
layer than in the litter. This is due, of course, to the relatively
high proportion of carbon to nitrogen in the litter, as will be
brought out later.

Owing to the extreme variations in weight and thickness of the
several horizons in forest soils the presenting of the data on a
percentage basis is somewhat misleading with respect to the total
amount of nitrogen in the profile. When recalculated on this basis
the figures for a few typical profiles to a depth of 24 inches are as
follows :

Podzol type

Mull

type

Profile

Pounds N

Profile

Pounds N

No.

per acre

No.

per acre

1

8129

21

17628

6

5417

22

5717

8

3154

23

11004

If the vertical distribution of this nitrogen in these profiles were
charted, the graph would be almost identical to that showing the

Chemical Properties

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0.291

Ol

0.913

1.400

0.116
0.044

0.017

3-.

0.901
1.159

0.083

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0.705
0.240

X

O CM CM CO Tf CM m

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1.512
1.194
0.097
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u

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782

Connecticut Experiment Station Bulletin 342

distribution of organic matter. The reader is referred, therefore,
to Figure 79. It must be kept in mind that in actual amount the
N values run approximately 1/30 to 1/50 of those for organic
matter.

Organic Matter

The best measure of soil organic matter is the organic carbon
content. The data in Table 9 are expressed in this form. To
convert to organic matter it is customary to multiply the carbon
content by the factor 1.724. This factor is considered satisfactory

POUNDS ORGANIC MATTER PER ACRE-INCH

10000 20000 30000 40000 0 10000 20000 30000 40000

TOTAL 404651 LBS

TOTAL 520736 LBS.

TOTAL 278109 LBS.

TOTAL 2192)9 LBS.

TOTAL 132606 LBS.

TOTAL 322168 LBS.

Figure 79. Vertical distribution of organic matter in pounds per acre
inch, and the total amount per acre to a depth of 24 inches.

for the mineral horizons, but it is not correct for materials high
in organic matter such as forest duff and peats. In a previous
paper (27) the writer showed that the stage of decomposition of
the duff must be taken into consideration when using a conversion
factor. The factors recommended are as follows :

Litter (freshly fallen leaves)

F layer (decomposing material whose original

structure is still discernible)
H layer (well decomposed, structureless humus)

1.85
1.80

Chemical Properties

783

CSj I ^

o 06 06 co" *' eg

>o "*■ CO

rnNin 00 ■— i
(\i CM* 0\ ' lo -^

OrnN00\0

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cvi .-I vo o r>! cj

OON^DiO'l-CO-t
CMLOCOCOCCCMco^f;

r-i C\ iH NO lO CO rM 6

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i-j CM "* cq is. u-j ro

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q oq oq t-. -h
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oo

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i-jovq

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00 CO VO **- CM t-i — i

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oor^ ON-*
mm I cm >-o

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^ t-H t~>. LO TJ- CO

C\ Tf' <-< o o cm"

o

o

^

"■+

T-i

CM

CM 1

1 ■*

1 ^

oo

~

1 cm"

1 o

hjfc<<eqpqpQU

784

Connecticut Experiment Station Bulletin 342

* to c q w h
cm c4 d «-5 wi 10

iO CO CO CO CM CM

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oq oq o\ r>.. <

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^ \d iO *-h cm' I ^h
COCM CM CM CO CM

\qoqrv.\qoq^i-oqo\

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coCMi-h.-iCOCM'-'CM

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_) fe ffi< pq cn pq CJ U

■>*■ CO CO

t^.CM

1 °°

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1 co

CN)

coqiocotN

co t-C c5 ^- CM
VO CO CM CM CM

I ■ • I

NO CO

coonoono

CO NO ON t^
COCM r-i-H

vdoNodrH I

iqooo I I i-j

ocm'o I I co

VO CO CO CM

jttHffi<<m pq

VO O CM CN) CM *»■ VO

o o- 1>. cq

co-ndd

^O CO CM CM

sigi

NO CM

"■> i CM

d vo

t^ Tt 1 t^ CM
CM' co I "* CO
iru-i r-lCM

■* CM t^. ON t>j

on u-i io r->! od

CMtJ-

CO CM On NO CM t>.
iri 00 •-< CO NO CO
CM CM CM »-i *-h CM

rf ,-h i-i

J fc < < pq eq cq U

Chemical Properties 785

The graphs in Figure 79 were constructed from data in which
the foregoing factors were used. Note the large quantity of organic
matter present in the B horizons of the podzolized soils. There is
a marked similarity between these graphs and those in Figure 78
showing the distribution of iron.

Nitrogen-Carbon Ratio

One characteristic of the majority of soils in the forests of
New England is their wide carbon-nitrogen ratio as compared with
agricultural soils. In no case have we found the ratio of the A
horizon to be narrower than 13:1 (Table 10). This is no doubt
due to the less rapid breaking down of the duff in the podzol types.
The material — present in all stages of decomposition — remains on
the surface for the most part. In the mull type, on the other hand,
as fast as the material breaks down it is incorporated into the
mineral soil primarily through the activity of earthworms.

The table shows also in the case of the B layers a wider ratio
in the podzol types than in the mulls.

Inspection of the data on Danish heath soils presented by Weis
(50) reveals that the proportion of C to N is invariably higher in
the leached layer than in any other horizon. This is not true in
the case of our New England soils.

Calcium

The data on total calcium is shown in Table 11. Based on the
dry weight of the soil, the H, Ai, and A2 layers are lowest in
calcium content, and either the F or the litter the highest. As a
rule the percentage of calcium increases from A2 downwards. This
distribution of calcium is more or less characteristic of all except
very immature soils. In podzol profiles the calcium distribution
does not coincide with that of iron or of organic matter, since the
calcium must first be displaced before the podzolization process
can take place. In this displacement the calcium is not concentrated
in the B layer, but apparently is diffused throughout the whole
of the subsoil. In a few cases there is a somewhat larger amount
in the C horizon.

The entire profile at South Coventry, Conn., (profile 25)
analyzes rather high in calcium, higher than any other profile
studied. It will be recalled (page 761) that the red pine growing
at this locality had the highest site index in the State.

786

Connecticut Experiment Station Bulletin 342

V

f~. CO i-H •* o\ VO
a\ t-» ro •«*• **• t-~

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i ID o

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o o o o o o

1 6-4

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oo

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h4tH<<pqpqequ

Chemical Properties

787

Comparison of the analyses of the mineral horizons used in
this study with those reported by Tamm (45) indicates that New
England soils are considerably more deficient in lime. This differ-
ence was not apparent in a comparison of the pH values.

At the time of the analysis of acid soluble iron, acid soluble
calcium also was determined. These data are given in Table 12,
while that showing the proportion of total calcium which is acid
soluble is in Table 13. The greater percentage of acid soluble
calcium in the A horizon of the mull is particularly conspicuous.

Table 12. Acid Soluble Calcium Expressed in Percentage

Strong podzol

Moderate podzol

Horizon

1

2

3

Ave.

6

7

8

Ave.

A2

0.068

0.068

0.103

0.080

0.009

0.127

0.033

0.056

B,

0.084

0.075

0.090

0.083

0.052

0.120

0.034

0.069

B2

0.107

0.116

0.227

0.150

0.018

0.320

0.070

0.136

B3

0.284

0.083

—

0.184

—

0.172

0.044

0.108

Q

0.203

0.356

0.320

0.293

0.090

0.273

0.058

0.140

Q

0.239

0.350

0.337

0.309

0.075

0.336

—

0.206

Humus type

Mull type

14

14a

15

18

Ave.

22

23

23a

24

Ave.

A,

0.033

0.071

0.090

0.042

0.059

0.134

0.157

0.041

0.279

0.153

A2

0.036

0.068

0.073

0.043

0.055

0.122

0.155

0.016

0.238

0.133

B,

0.014

0.189

—

0.068

0.090

0.119

0.082

—

—

0.101

B2

0.007

0.063

0.072

0.025

0.042

0.153

0.155

0.024

0.183

0.129

B3

0.189

0.090

—

—

0.140

Q

—

0.179

0.066

0.064

0.103

0.135

0.073

—

0.155

0.121

c2

—

—

0.089

—

—

—

0.096

—

—

—

Table 13. Percentage of Total Calcium that Is Acid Soluble

Strong podzol type

Moderate podzol type

Horizon

1

2

■ 3

Ave.

6

7

8

Ave.

A2

15.4

21.4

18.4

3.2

13.4

40.7

19.1

B,

12.1

17.8

15.0

22 2

11.9

36.2

23.4

B2

16.3

24.6

20.5

8.1

23.4

61.4

30.9

B3

30.1

19.2

24.7

—

—

15.5

—

Q

25.1

48.6

36.9

—

24.2

30.4

27.3

c2

25.8

—

—

18.2

—

—

—

Humus type

Mull type

14

14a

15

18

Ave.

22

23

23a

24

Ave.

A,

11.3

32.4

28.0

23.9

25.0

50.6

36.8

37.5

A2

10.4

—

27.4

23.0

20.3

17.8

56.2

—

27.1

33.7

B,

5.1

—

—

42.7

23.9

18.8

40.6

—

—

29.7

B2

4.2

—

19.2

21.4

14.9

21.2

57.5

—

21.3

33.3

B3

—

—

—

—

—

29.1

49.1

—

—

39.1

C,

—

—

29.3

40.5

34.9

19.9

45.3

—

14.9

26.7

788

Connecticut Experiment Station Bulletin 342

A somewhat different picture of the calcium relations may be
seen when the data are based on the ash instead of dry weight.
Table 14 contains such data. Differences in the calcium content of
the various horizons are decidedly more pronounced. In profile
No. 4, for example, calcium based on dry weight (Table 11) is
approximately the same in the upper H layer as it is in Bi, B2, and
Ci. Calculated on the ash basis, however, it is readily seen that
the calcium content of upper H is 12 or 13 times as great as that
of the B and C horizons. Again, differences in the Ca content of
the F layers of the several profiles are much more conspicuous
and not always in the same order when based on the ash content.

POUNDS CALCIUM PER ACRE-INCH

1000 2000 3000

1000 2000 3000 4000 5000 6000

TOTAL S0J6I LBS.

L „

4?

PROFILE 6
PODZOL

B}

%

TOTAL 18930 LBS.

B3

*l

PROFILE 8

A£

PODZOL

B,

B2

TOTAL 18107 LBS.

c,

TOTAL

139286

LBS.

PROFILE

22

MULL

TOTAL

47381

LBS.

\

PROFILE 13
MULL

TOTAL 15037 LBS.

Figure 80. Vertical distribution of calcium in pounds per acre inch, and
the total amount per acre to a depth of 24 inches.

In the discussion of nitrogen the differences between data given
in percentage and those given in pounds per acre were pointed out.
These differences are even more striking in the case of calcium, as
seen in Figure 80. Although the percentage composition of the
duff is high (Table 11), yet in total amount per acre it is quite
insignificant when considered in relation to the Ca in the lower
mineral horizons.

Chemical Properties

789

S3

& y

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u

5 x

u

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1 ^->U-J 1

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ON

r-» on

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pasEq E3

• 1

rHO

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paseq bq

•

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CM' h

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r^ i o

■ o o

53

qsy

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CO CM

J>I co

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0\ ON

•jm Xap uo

r-r ■ CO

CM | CO

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paseq bq

CM .-H

qsB uo

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On in-*
CM CM CM 1

VO

paseq bq

^ _; 1

odd '

-a

o

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qsy

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■* coco |

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uind

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pasBq B3

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CO CM O

h CM CM CM,

paseq eq

odd

d odd

LffiK<<pqmu

790

Connecticut Experiment Station Bulletin 342

On the other hand it must be recognized that only a relatively
small portion of the total is available to the plant at any one time,
and that the bulk of the available calcium is to be found in the
organic portion of the profile. This is shown in the data for
exchangeable calcium (Table 15).

Table 15.

Exchangeable Calcium

in Percentage

Horizon

Strong podzol type

Moderate podzol type

1

2

3

4

5

Ave.

6

7

8

9

10

Ave.

Litter

.431

.372

.289

.331

F

—

.700

—

.505

.256

.487

.380

.235

.370

—

.414

.350

H

.266

.264

—

.047

.332

.227

.214

.073

.039

.328

.260

.183

A2

.011

.007

.023

.003

.006

.010

.009

.009

.006

—

—

.008

B,

.028

.012

.014

.003

.003

.012

.008

.005

.004

.009

.019

.009

B2

.012

.007

.004

.004

.002

.006

.005

.004

.007

.006

.006

.006

B3

.004

.023

—

—

—

.014

—

—

.009

—

. —

.009

Q

.001

.015

. —

.006

—

.007

.004

—

.016

.008

.007

.009

Q

.002

.001

—

—

—

.002

.004

—

—

—

.006

.005

Raw humus type

Humus type

Mild humus type

11

12

13

14

IS

16

17

Ave.

18

19

20

Ave.

Litter

.180

.313

.256

.250

F

.310

.562

.570

.290

.147

—

.260

.357

.200

.158

.315

.224

H

.083

.138

.190

.138

.113

.414

.295

.196

—

.125

.340

.233

A,

—

—

—

.008

.006

—

—

.007

.011

—

—

A2

—

.011

.008

.007

.006

.037

.006

.013

.005

.007

.020

.011

B»

.004

.006

—

—

.026

—

—

.012

—

—

—

—

B2

—

.007

—

—

—

—

—

—

—

.009

Q

—

.006

—

—

—

—

—

—

—

—

—

Mull type

21

22

23

24

25

26

27

28

29

30

31

Ave.

Litter

.517

. .

.535

.420

.552

.455

.259

.396

.448

F

—

—

.422

.273

.432

.804

.483

A,

.167

.025

.074

.072

.027

.116

.081

.049

.037

.023

.290

.087

A2

—

.008

.072

.045

.021

.037

B,

—

.006

—

. —

.024

—

. —

—

—

—

.008

.013

Ba

.042

—

—

—

.020

—

—

—

—

—

.007

.023

Q

.013

.009

.011

The relation of exchangeable to total calcium is to be found
in Table 16. Here it is seen that the exchangeable calcium in forest
soils appears to comprise from 30 to 75 per cent of the total
calcium in many of the duff layers and less than 5 per cent in
the B and C horizons. The percentage in the case of the A horizon
is rather variable but may be said to be between 2 and 20 per cent.
It is quite apparent that the proportion of calcium in the exchange-
able form in the mineral horizons of these forest soils is con-
siderably less than in the agricultural soils of the Middle West

Chemical Properties

791

where in the better soils the proportion is about 40 to 60 per cent
(26).

The "pumping" action of forest trees — removing nutrients from
the mineral soil and depositing them in the debris on the surface —
is strongest in the case of calcium (25). This is particularly true
of the exchangeable Ca, since it is the portion most likely to be
utilized by the plant.

Magnesium.

Rather incomplete data on the magnesium content indicate that,
like calcium, it increases with depth below the Ai horizon (Table
17). The only striking difference between types occurs in the
case of the strongly podzolized soils in New Hampshire, which
are considerably lower in magnesium than most of the other

Table 16.

Proportion of Total Calcium That Is Exchangeable
Expressed in Percentage

Strong podzol type

Moderate podzol type

Horizon

1

2

3 | 4 | S

Ave.

6

7 8 9

10

Ave.

Litter

F

H

A2

B,

B2

B3

C,

Q

66.6
2.5
4.0
1.8
0.4
0.2
0.2

86.4

71.3
2.2
2.9
1.5
5.3
2.1

—

59.2

53.9

2.8

1.3

1.5

2.2

63.2

74.6

70.3

4.3

3.4

1.2

73.4
65.5
3.0
2.9
1.5
2.9
1.5

55.4

74.7
3.2

3.5
2.1

1.0

57.8

57.3

0.9

0.5

0.3

43.3
33.2
6.8
3.8
6.4
3.2
8.2

36.9

53.8

1.8
0.5

1.4

31.6
43.8
66.0

3.0
0.8

0.7
0.4

34.3

50.1

57.0

3.6

2.5

2.0

3.4
0.7

Raw humus type

Humus type

Mild humus type

11

12 | 13

14

IS

16

17

Ave.

18 | 19

20

Ave.

Litter

F

H

A,

A2

B,

B2

Q

38.3
42.0

69.2
0.5

35.8
43.4
22.0

1.8
1.0
0.9
0.7

41.5
32.4

1.7

44.6

48.6

2.7

2.1

41.9

60.3
2.1
2.2
6.8

27.6

62.5

4.3

30.3
69.4

0.7

33.9

40.6

52.1

2.4

2.1

2.8

54.5
7.3

2.6

32.0
49.2

0.5

33.3
64.4

2.2

1.0

39.9
56.8

1.8

Mull type

21

22 | 23

24

25

26

27

28

29

30

31

Ave.

Litter

F

A,

A2

B,

B2

c,

42.7
9.1

2.1
0.7

4.7
1.1

1.0

61.9

2.4
2.6

39.1

9.4

5.1

41.8

2.4

2.2

4.0

29.4

15.7

29.2
13.7

43.3

10.3

43.4
2.4

31.4
2.8

30.0
66.0
46.2
8.0
3.3
2.5
2.4

35.6
52.2
10.8
4.2
2.2
2.9
1.6

792

Connecticut Experiment Station Bulletin 342

Table 17. Total Magnesium Expressed in Percentage

Horizon

Strong podzol type

Moderate podzol type

1

2

4

5

Ave.

6

7

8

9

10

Ave.

F

0.07

.

H

—

—

—

0.11

—

—

—

—

—

—

—

A2

—

0.17

0.02

0.00

0.06

0.43

0.43

0.18

—

—

0.35

Ba

0.22

0.20

0.06

0.04

0.13

0.31

0.46

0.25

0.25

0.30

0.31

B2

0.24

0.29

0.06

0.01

0.15

0.36

0.71

0.31

0.77

0.40

0.51

B3

—

0.13

—

—

—

—

—

0.37

—

—

—

Q

—

0.34

0.07

—

0.20

—

0.85

0.35

0.43

0.68

0.58

c2

0.28

—

—

—

—

0.85

—

—

—

0.94

0.90

Raw humus type

Humus type

Mild humus type

11

12

14

15

16

Ave.

18

19

20

Ave.

F

0.26

—

—

—

—

—

—

0.11

—

H

0.08

0.38

—

—

—

0.23

—

0.08

—

—

A,

—

—

0.56

0.43

—

0.50

0.30

—

—

—

A2

—

0.57

1.10

0.34

0.47

0.62

0.27

0.58

0.27

0.37

B*

0.25

0.59

0.73

0.26

, —

0.46

0.29

—

—

—

B2

—

0.62

0.96

—

—

0.79

0.29

—

0.31

0.30

Q

—

0.55

—

0.38

—

0.47

0.25

—

—

—

Mull type

21

22

23

24

25

26

28

29

30

31

Ave.

Litter
F

Ax

—

—

—

—

—

—

0.28

—

—

—

—

0.76

0.35

0.30

0.72

0.67

0.74

0.39

0.55

0.51

0.46

0.55

A2

—

0.41

0.31

0.90

0.37

0.50

Bx

—

0.37

0.53

0.80

0.65

—

—

—

—

0.40

0.55

B2

1.17

0.45

0.80

0.89

0.40

—

—

—

—

0.41

0.69

Q

1.27

0,44

0.69

0.76

0.52

0.73

localities. Undoubtedly this is due to a difference in the parent
material rather than to any process of soil development, as indi-
cated by analyses of the C horizon.

When we compare the magnesium with calcium, Table 18, we
see that the ratio Mg:Ca varies from less than 0.2 to as high as
5.72. As a group the New Hampshire soils show the lowest ratio.
Within the profiles the ratio in the duff portion is lower, on the
whole, than it is in the mineral horizons.

Table 18. Ratio of Magnesium to Calcium

(c7 =R)

V / Mg '

Strong podzol type

Moderate podzol type

Horizon

1

2

4

5

Ave.

6

7

8

9

10

Ave.

F
H

A2

—

—

—

0.22
0.44

—

—

—

—

—

—

—

0.53

0.19

0.36

1.51

0.45

2.21

1.39

Bt

0.31

0.48

0.25

0.42

0.36

1.33

0.46

2.70

0.51

0.47

1.09

B2

0.37

0.61

0.27

0.05

0.33

1.65

0.52

2.76

0.59

0.52

1.21

B3

—

0.29

—

—

—

—

—

1.30

—

—

—

Cx

—

0.47

0.29

—

0.38

—

0.75

1.83

0.75

0.63

0.99

c2

0.30

—

—

—

—

2.06

—

—

—

0.60

1.33

Chemical Properties

793

Table 18. (Continued.)

Raw humus type

Humus type

Mild humus type

11

12

14

15

16

Ave.

IS

19

20

Ave.

F

0.36

0.22

H

0.66

0.61

—

—

0.63

—

0.31

—

—

A,

—

—

1.92

1.55

1.73

1.98

0.41

—

1.20

A3

—

0.94

3.18

1.27

0.55

1.49

1.47

—

0.30

0.89

B,

0.29

0.68

2.67

0.69

—

1.08

1.85

—

—

—

B2

—

0.82

5.72

—

—

3.27

2.75

—

0.35

1.55

Q

—

0.69

—

1.69

—

1.19

1.59

—

—

—

Mull type

21

22

23

24

25

26

28

29

30

31

Ave.

Litter

0.22

F

A,

0.41

0.66

0.95

0.94

0.59

1.00

0.83

0.37

0.61

0.73

0.71

A2

—

0.59

1.13

1.03

1.40

1.04

B,

—

0.59

2.62

0.96

0.59

—

—

—

—

1.77

1.31

B2

0.58

0.62

2.96

1.04

0.79

—

—

—

—

1.53

1.25

c,

0.71

0.64

4.25

0.72

1.35

1.53

Exchangeable Hydrogen, Total Base Capacity and Percentage
Saturation.

The process of podzolization consists of the displacement of
bases by hydrogen, and is controlled to a large extent by the degree
to which the soil is saturated with bases. The more completely this
displacement takes place the more thoroughly a soil is podzolized.
Data relative to these soil properties are given in Table 19.

It is readily seen that exchange capacity is identified with the
organic matter content. McGeorge (29, 30) working with peats,
mucks and forest duff, found a good correlation between total
replacement capacity and organic carbon. In this study it was
found that a positive relation occurs within the group of samples
analyzing less than 20 per cent carbon. Also the samples high in
carbon possess a high exchange capacity. But within the high
carbon group, that is, between 35 and 55 per cent, the correlation
is practically negative. The relatively low proportion of hydrogen
to base in the litter and F layer of the Meshomasic profile (No. 11)
is surprising.

It will be noticed that in a number of samples the amount of
hydrogen present exceeded the total exchange capacity. This would
indicate the presence of free acid. Such a condition is highly
probable in the podzol and raw humus types, but hardly in the
mulls. Just why the hydrogen exceeds the total capacity in the
Groton profile (No. 22) is not clear. The difference is small and
may be partly experimental error.

794

Connecticut Experiment Station Bulletin 342

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796

Connecticut Experiment Station Bulletin 342

Phosphorus and Potassium.

Eight profiles were analyzed for total and soluble phosphorus
and replaceable potassium. The results are found in Tables 20
and 21. The high phosphorus content of the whole profile of the
Bethlehem hardwoods is worthy of note, as is the relatively high
amount in the B horizon of the Rainbow soil. The latter soil, it
will be recalled, is a coarse sand.

By far the bulk of the soluble phosphorus is to be found in the
organic horizons, very little of the phosphorus in the subsoil being
soluble.

What has been said regarding soluble phosphorus applies equally
well to exchangeable potassium, only a very little being found in
the B and C horizons. The Bethlehem profile is outstanding again
in the amount of replaceable potassium present in the A and B
layers.

When compared with data obtained by Tamm (45) we find
considerable similarity in total phosphorus content between our
New England podzolized soils and those of Sweden. On the other
hand the soluble phosphorus in the subsoils of podzol profiles
appears to be higher in Sweden than in New England, although
some allowance must be made for the difference in methods of
analysis used. Tamm used citric acid as a dissolving agent. Nemec

Table 20. Total and Soluble Phosphorus

Podzol Raw humus

•

1 | 4

11

12

Total
P

%

Soluble

P
p.p.m.

Total
P

%

Soluble

P
p.p.m.

Total
P
%

Soluble

P
p.p.m.

Total
P

%

Soluble

P
p.p.m.

Litter

F

H

A2

B,

B2

Q

.175
.127
.014
.028
.045
.038

345
96
3
6
3
3

.150
.074
.012
.037
.048
.049

440
93
0
5
3
4

.080
.093
.095

.034

355
285
136

4

.080
.135
.089
.050
.046

.036

195

170

32

8

3

5

Humus

Mull

18

21

23

31

Litter

F

H

A,

A2

B,

B2

Q

.139
.032

.037
.070

.026

110

19
11
42

9

.102

.077
.095
.108

205

37
27
57

.088

.104
.087
.034
.054
.022

18

9

Tr.

7
6

.092
.139

.100
.072
.049

.045

268
209

29

11

6

6

Biological Studies

797

(35) found .040 to .215 per cent citric acid soluble P in the humus
layers of coniferous woods, and .002 to .044 per cent in the mineral
layer. Farm soils ranged from .035 to .220 per cent.

Aarnio (1) studying the brown soils of Finland reports 0.16,
0.08, 0.12, and 0.09 per cent phosphorus in the A2, Bi, B2, and C
horizons respectively.

Table 21. Replaceable Potassium in p.p.m.

Podzol

Raw humus

Humus

Mull

1

4

6

11

12

18

21

23

31

Litter

F

H

Ax

A2

B1

B3

c,

902
404

33

51

2

4

1342
252

19
36
26
27

1049
960

42
44
43
15

3400

857
558

77

1374

1151

533

89
28

17

465

34
15
13

14

928

217
80
37

840

135

54
24
45
62

1473
1290

425

116

29

31

BIOLOGICAL STUDIES

Nitrogen Transformation

The work of Hesselman (19), Nemec and Kvapil (36), Melin
(31), and others indicates the importance of nitrification in forest
soils. In mull types, where there is little or no accumulation of
duff, the A horizon of the mineral soil is most important in this
nitrification process ; but in the case of podzol types or where a
thick layer of duff persists the feeding roots of the trees are con-
fined quite largely to the organic accumulation on the surface,
hence it is in this portion of the profile that the soluble nitrogen is
utilized. In the underlying mineral layers practically no nitrogen
transformation takes place.

Procedure and Method of Anaylsis

It would be desirable to determine the nitrogen changes in the
field under natural conditions but such a procedure would require
frequent samplings throughout a period of several years in order
to overcome violent fluctuations resulting from marked changes
in the weather and associated environmental conditions. Therefore
the practice commonly followed is to bring the samples into the
laboratory, and incubate them under optimum conditions. Although
this does not simulate field conditions it puts all samples on a
uniform basis and the results obtained are comparable. As far as
possible, samples were collected in the fall after the deciduous

798 Connecticut Experiment Station Bulletin 342

leaves had fallen. This enables one to collect the fresh litter if
desired, and the fermentation, or F, layer has had a year in which
to decompose.

Some of the samples were kept in closed (but not air tight)
containers until ready to use, which prevented their drying out.
The others were allowed to air dry and were kept in this condition
until the experiment was started. In either condition, they were
chopped into particles one-fourth inch or less in size in a Hobart
food chopper before incubation. Definite amounts were then
made up to optimum moisture as determined by observation, lime
or other material added if desired and the samples placed in either
jelly glasses or 12-ounce wide-mouth bottles and kept at room
temperature. Free movement of air was provided by one or two
small holes in the stopper. The incubation period was usually 3
months. Ammonia and nitrates were determined at the beginning
and the end of the incubation period.

For ammonia the samples were leached with half normal KC1
solution and the leachate distilled upon the addition of magnesium
oxide.

In determining nitrates the procedure for clarification recom-
mended by Harper (17) was employed, generally with success.
Nitrates in the clarified solution were estimated by the usual
phenol-disulfonic acid method.

Inoculation was not practiced except in a few specific cases.

Presentation of Results

Owing to the lack of absolute control over all conditions under
which the several experiments were carried on it is necessary to
confine comparisons very largely to the samples within any one
experiment. This is especially true in these tests since there was
some variation in procedure.

Samples not previously dried. The first set was run during
the early winter of 1928-29 on undried samples. The data are
given in Table 22. In Figure 81 the untreated samples are grouped
by horizons. By far the bulk of the available nitrogen is in the
ammonia form, in all excepting sample No. 60. On the other hand,
lime causes the accumulation of nitrates at the expense of ammonia.
In general the increase in ammonia of the Untreated soils is less
for the H than for the F layers. The inoculation of sample 52,
a raw humus layer, with a water extract of 60, the Ai of a mull
type, caused some reduction in the amount of ammonia produced.
Partial sterilization before inoculation brought about a marked
limitation in ammonia production.

On the other hand inoculation of No. 60 with No. 52 had a
tendency to increase both the ammonia and nitrates. Sterilization

Biological Studies

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800 Connecticut Experiment Station Bulletin 342

before inoculation resulted in somewhat less ammonia and almost
no nitrates.

The second experiment ran from March to June, 1929, on a
different set of soils. Ten, twenty-five or fifty grams of soil were
used, depending upon its bulkiness. The results are recorded in
Table 23.

In general the results are similar to the first experiment. Partial
sterilization of No. 77 appeared beneficial to NH3 production but
hindered NOa formation. Inoculation of a partially sterilized
sample with about one-ninth by weight (W. F. basis) of No. 98
decreased the NIL somewhat.

Inoculation of sample 85 with No. 126, which by itself am-
monified strongly, brought about only a slight increase. Dextrose

PARTS PER MILLION

0 500 1000 1500 2000 2500 3000

SOIL

"a F LAYERS

PODZOL .^i^MM^^^Hi

5 i^^mm—^^^^^^^^mmmmm—^K
RAW HUMUS32WKmmmmmm^^^mm^^^mmm^^i^^

MULL 38\

PODZOL 45l
521

RAW HUMUS 3 31

NH3 -N

H LAYERS —N03'N

MINERAL SOIL (A,)

MULL 3 9 ■«

Figure 81. Amount of ammonia nitrogen and nitrate nitrogen in the soil
after a three-month incubation. (Table 22.) First set, soil not previously
dried.

added in addition had practically no effect. The inoculation of No.
120 with No. 85 and the further addition of lime brought about
an enormous increase in nitrates. The sample was not tested
for NHa.

Lastly, inoculation of No. 126 with No. 85 greatly increased
the NOa content, and the use of lime in addition more than doubled
the nitrates.

Samples previously air dried. In the winter of 1929-30 a
third experiment was carried out, this time on previously air-dried
material. No inoculations or other treatments were applied. Table

Biological Studies

801

24 and Figure 82 contain the data. Ammonia was determined at
the end of one month as well as three months. Nitrates were run
only after three months.

The ammonia content of the Cherry Mountain samples, particu-
larly the F layers, was quite high at the beginning of the experi-
ment but the increase during the incubation period was large,

SOIL
NO.

P0DZ0L3-4*

7*

9 •

17 *

25 i

185*

192.H

306*

HUMUS

3th

3/7*

363 ■

367'

313 t

PODZOL 8 l

ro\

18 I
T86\
I93\
307*

HUMUS 311 '/z\
3/8l
3641
368 i

500

PARTS PER MILLION

1000 1500 2000

2500

3000

F LAYERS

NH3_ - N
NOj - N

H LAYERS

MULL

I77\
3/0 i
374i

198 l

MINERAL SOIL (A.)

(ROTT/NG LOG)

Figure 82. Amount of ammonia nitrogen and nitrate nitrogen in the
soil after a three-month incubation. (Table 24.) Third set, soil previously
dried.

nevertheless. As a rule the litter samples yielded little or no am-
monia and, of course, no nitrates. This is due to the very wide car-
bon-nitrogen ratio of this material. All the available nitrogen
present is used immediately by the decomposing organisms. In
order to provide an accumulation of ammonia it would be neces-
sary to add a large quantity of readily available nitrogen, as
will be seen in later experiments.

802

Connecticut Experiment Station Bulletin 342

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Connecticut Experiment Station Bulletin 342

Sample 198 is a rotting spruce log that was collected and pre-
served in a moist condition. Spruce seedlings survive and seem
to grow quite vigorously on these rotting logs. In the foregoing
experiment ammonification was not especially marked although the
initial ammonia content is fairly high. Further consideration of
this material is postponed for the present.

Inoculation Experiment

A special inoculation experiment was carried out in 1930 to
supplement rather incomplete tests of a similar nature that had
been previously made. This was done with air dried materials
made up to optimum moisture, and inoculated with a water extract
rather than with soil itself. The samples used were from the same
group as those of the 1929-30 experiment. The plan was to inocu-
late a sample that normally did not ammonify with an extract of
a sample that by itself yielded a large quantity of ammonia. Also
the opposite was tried, inoculating a high ammonia sample with
material from a low ammonia sample.

The results, shown in Table 25, indicate very little influence of
inoculation. It is concluded, therefore, that if these materials
contain any substances that either stimulate or inhibit ammonifica-
tion such substances are not soluble in water.

Table 25. Nitrogen Transformation, Inoculation Experiment, 1930

Soil No. Horizon

NH-N p.p.m.

Previous
analysis

1 month
incubation

178

Lit.

Plus extract of 318

0

6.7
18.7

192

Lit.

Plus extract of 185

41

13.3
26.6

185

F

Plus extract of 178

896

680.0
608.0

317

Lit.

Plus extract of 318

52

23.0

5.0

318

H

Plus extract of 31 51

569

588.0
593.0

367

F

Plus extract of 3682
Plus extract of 185

40

40.0
0.0

8.0

■'Previous analysis of No. 315, 32 p.p.m.
^Previous analysis of No. 368, 274 p.p.m.

Biological Studies 807

Effect of Treatment

A fifth experiment was carried out in the winter of 1930-31
in which several treatments were used. In connection with another
greenhouse experiment, samples were collected from a scarlet oak
stand in Bethany, Conn., under which there was a rather thick
layer of raw humus, a typical poor condition for this locality and
from a healthy, rapidly growing mixed hardwood stand near Lake
Beseck in Middleneld, Conn, which had an excellent crumb mull.
These samples were taken as follows :

Bethany (Profile 13) Beseck (Profile 22a)

S 358 F layer S 362 Litter

359 H layer 363 A,

360 Aa 364 Composite

361 Composite

The composite consisted in each case of a mixture of the hori-
zons in question in their natural proportions similar to what one
would have were he to plow the soil to include about 4 inches of
mineral soil. In addition there were included in the experiment
samples from a mull type and a raw humus type in eastern
Connecticut and a mull in Woodbridge, Conn. (Lake Chamberlain).

Treatments when specified consisted of the following materials :
Lime = precipitated chalk ; nitrogen = bloodmeal calculated to
yield 800 to 1000 p. p. m. of nitrogen as used ; PK = KtLPO.
20 mg. per sample. From 20 to 100 grams of soil were used,
depending upon its bulkiness. These data are presented in Table
26.

The following points are worthy of note.

1. The large accumulation of ammonia in S 358 untreated, and the marked
loss of ammonia in S 362. This again is identified with the differences
in C-N ratios.

2. The striking decrease in ammonia and in most cases the resulting increase
in nitrates where lime was used.

3. The increase in ammonia where nitrogen was added. In no case, how-
ever, did the whole of the added bloodmeal nitrify. Observe the rather
close relation between the percentage of added N nitrified and the C-N
ratio.

4. The NPK treatment giving slightly better results than N alone, except
in the case of S 362.

5. LNPK causing a very marked increase over lime alone in samples
S 360 and S 363, both mineral layers, but not in the other three samples
so treated.

6. In sample S 362 none of the treatments had any appreciable effect in
overcoming the handicap of a wide carbon nitrogen ratio. In the green-
house it was necessary to add large quantities of soluble nitrogen in
order to grow a crop on this material.

7. Comparing the check with the lime treatment, it is evident that in the
F layers lime resulted in a much lower accumulation of soluble nitrogen
than was the case in the untreated sample ; in the H layers there was a
slight reduction, but in the mineral horizons lime increased the soluble

808

Connecticut Experiment Station Bulletin 342

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Biological Studies

809

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810 Connecticut Experiment Station Bulletin 342

nitrogen content. Although the C - N ratio has some part to play in
this, it does not account for all the differences found. Nor can one
find any correlation with the pH of the incubated soil at the end of 3
months. It may be identified with the organic constituents such _ as
lignin and cellulose, as differences in these constituents in similar
horizons have been found by Watson, Waksman and others.

Natural Moist Condition versus Previous Drying

Samples of the H layer collected in July, 1931, near Waterville,
N. H., and North Colebrook, Conn., were divided into two portions,
one being either wrapped in wax paper or put into a tin milk can
and the other being allowed to air dry. In November all samples
were prepared as usual and set up for incubation. Similar com-
parisons in a small way had been made in connection with some of
the preceding experiments. All of the data bearing on this question
are to be found in Table 27.

Apparently drying stimulates ammonia formation and, possibly
to a limited extent, nitrate formation, although the data in the latter
case are conflicting.1 Where lime was used on these samples the
results tend to be very erratic. From the foregoing data one is
led to believe that previous drying makes but little difference in the
amount of nitrogen transformed in a 3 months period of incubation.
One should be consistent in his procedure, however, if comparative
results are to be obtained.

Incubation appears to have raised the pH of the unlimed samples,
due no doubt, to the increase in ammonia. Note that the North
Colebrook wet sample that actually decreased in ammonia also
decreased in pH. Lime increased the nitrate content which, as
nitric acid, very markedly reduced the pH of the original limed soil.
The hydrogen ion concentration at the start was determined one-
half day after the samples had been moistened and limed.

Correlations of Nitrification with Chemical Composition

A positive correlation between ammonia plus nitrates and pH
after 3 months incubation is shown in Table 28. While individual
samples vary greatly the averages are in agreement with the data
presented by Hesselman (19), although he deals with the ammonia
nitrogen separately from nitrate nitrogen.

The correlation of ammonia nitrogen and C - N ratio is given
in Table 29. Here we see the average maximum occuring when
the ratio varies between 20 and 30 to 1.

^ull (20) observed that the general level of ammonia and nitrates after incubation
was lower in the set in which the soil had been air dried than in a previous set not
allowed to air dry. He did not, however, run both sets concurrently, as was done in
this work.

Biological Studies

811

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Connecticut Experiment Station Bulletin 342

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SOIL NUMBER

25

O) C
C5 r^

17

Figure 83. Relation of ammonia nitrogen content after a three-month
incubation to other soil properties. Podzol soils, F layers only.

Biological Studies

813

In Figure 83 the F layers from podzol soils are arranged in
order of increasing amounts of ammonia formed upon incubation,
and comparison is made with pH and with the total nitrogen and
total calcium content of these soils. The correlation is closer in the
case of pH and calcium than it is with nitrogen. Observe that pH,
Ca and N are very much higher in No. 9 than in No. 7. The latter
is from an almost pure spruce stand, while sample 9 came from
a clear cut spruce-hardwoods plot. The difference in C - N ratio
(No. 7 = 41.5; No. 9 = 22.2) is sufficient to account for the
superior ammonification in No. 9. Comparing samples 9, 17 and

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18

SOIL NUMBER

Figure 84. Relation of ammonia content after a three-month incubation
to other soil properties. Podzol soils, H layers only.

25, which correspond to plots 1, 2, and 3 of the Cherry Mountain
series, we note that plot 2 is poorly drained and the stand contains
a much larger proportion of conifers than plot 3. This would
account for the more acid reaction and the lower Ca content.

In the case of the H layers of podzol types (Figure 84) excellent
agreement is found between NFL-N, calcium, and pH. Total N
does not correlate nearly so closely.

The ammonia formed in mild humus (twin mull) samples is
correlated fairly well with total nitrogen content and also calcium
as far as it goes (Figure 85). It may be mentioned here that the

814

Connecticut Experiment Station Bulletin 342

exchangeable calcium of sample No. 126 is considerably in excess
of any of the other samples concerned in this group. Apparently
reaction is of less consequence in this case.

All of the factors involved agree excellently with the ammonia
nitrogen of the H layers of the mild humus type (Figure 86).

Correlations with Phosphorus and Potassium

The ammonia content of two groups of samples was compared
with total phosphorus, soluble phosphorus, and replaceable potas-
sium. The correlations were practically nil, hence no data are
given.

Table 28. Correlation of NH3-N + N03-N and pH
Organic layers

pH

3-3.5

3.5-4.0

4.0-4.5

4.5-5.0

5.0-5.5

5.5-6.0

465

563

10

0

622

728

633

736

677

25

1025

2819

892

1129

823

43

1141

1032

1232

845

1025

1331

1279

1307
1439
1543
1680

897
940
1005
1073
1148
1217
1545
1886
2057
2082
2215
2235
3862

1215
1403
1845
2172
2272
2520
2715
3359

2920

Ave.

860

1204

1442

1550

1408

1773

Mineral layers

56

62

157

72

86

157

142

101
116
160
182

272
374

Avera

ge

90

169

157

133
266

200

Biological Studies

815

Table 29. Relation of NH3~N to C-N Ratio
Organic layers

C:N , .

0-10

10-20

20-30

30-40

40-50

50-60

60-70

70-80

80-90

573

244

188

0

0

0

0

26

563

280

75

0

8

12

892

992

465

845

10

10

1032

583

1025

15

71

1073

633

1148

15

1200 ■

736

1543

25

1215

823

43

1232

897

1439

940

1545
1845
1875
2075
2235
2272-
2486
2625
.2828
3675

1017
1120
1279
1295
1403
1656
1675
2045
2172
2189
3359

Ave.

1708

1238

773

15

22

6

459

Organic Matter Decomposition

The kind and amount of duff on the forest floor are dependent
among other things upon the rate and completeness of decomposi-
tion. The best method of making comparisons in this respect is by
taking the samples to the laboratory and measuring the rate of
decomposition under uniform conditions. Perhaps the most satis-
factory measurement is the amount of carbon dioxide evolved in
a given time.__

Results Over a. 46 Day Period

The samples' wereprepared "as" described for the nitrogen trans-
formation experiments and put into 12 ounce wide mouth bottles
connected with some suitaM"e;device (to be described) for meajsurf
ing the CO*. ; :■":.? - • ---- '■---* ^-: ■■- --" '-"--

For the first test, carried out in the "winter of 1928-29, the
amount of soil used was governed by its carbon content, the object
being to have the same amount of organic carbon in each sample,

816

Connecticut Experiment Station Bulletin 342

using 10 grams of soil containing 40 per cent C as a basis. In other
words each sample as used contained a total of 4 g. of carbon.
The bottles were equipped with a two-hole stopper in the one of
which was inserted a soda-lime tube. In the other hole was placed
a glass tube bent at right angles, the horizontal end of which was
connected to the bulb end of a Meyer absorption tube. A battery
of 12 such sets was connected to a water pump. Aeration at a slow
rate was carried on for one hour each day. The CO2 was absorbed

69 97

NUMBER

Figure 85. Relation of ammonia nitrogen content after a three-month
incubation to other soil properties. Humus type profile, F layers, only.

by standard KOH, the carbonates precipitated with BaCL and
the whole titrated with HC1. The data are given in Table 30.

The F layers in all cases evolved considerably more CO* than
did the H or Ai layers. This is to be expected since the C - N ratio
is wider in the F portion. In the H and the organic portion of the

Biological Studies

817

Ai the more readily decomposed portions have already been broken
down, leaving the more resistant substances of which lignin is the
best known.

The most rapid decomposition occurs during the first few days,
with a gradual dropping off with the passage of time. Sample No.
38, however, not only has a higher initial evolution but maintains
a higher rate throughout, dropping off but little. Were the experi-
ment to continue for a longer period of time, all samples would

Table 30. Organic Matter Decomposition as Measured by Evolution

of Carbon Dioxide. (Samples Not Previously Dried) Mgms. of

CO, Average per Day

Days

Profile No. 14

Devil's Hop Yard

Raw humus

Soil

No. 32

F

Soil

No. 33

H

Profile No. 24

Devil's Hop Yard

Mull

Soil

No. 38

F

Soil

No. 39

A

Profile No. 6
Bigelow
Podzol

Soil

Soil

No. 44

No. 45

F

H

2
4
7
11
14
20
25
32
39
46

Accum. total
W. F. wt. soil gtn.
Ave. per gm. soil
Percent. CO„ evolved

28.3

10.8

24.2

8.3

24.8

8.6

17.5

5.9

18.1

6.8

16.3

6.2

17.0

7.7

16.7

9.5

15.9

12.5

13.2

10.7

805.9

410.7

8.98

10.13

89.7

40.5

d 5.5

2.77

38.3

11.9

28.9

33.6

9.1

25.5

35.4

8.8

24.0

25.3

6.5

17.3

29.9

8.1

18.3

27.3

6.9

14.5

31.9

7.2

14.4

32.2

7.4

15.3

31.9

6.9

17.2

24.3

5.3

15.7

1381.4

332.4

799.8

13.64

50.9

9.79

100.6

6.5

84.9

9.42

2.27

5.48

11.1

9.4

9.1

6.5

7.5

6.3

6.1

6.1

6.2

5.3

306.4

10.34

29.5

2.08

drop off to a much lower level. Observe that the amount of COa
evolved in percentage of the total amount originally present, varies
considerably in the F layers, but is more constant in the H and
Ai horizons.

Seven Day Experiments

It was observed that the results obtained at the end of one week
were comparable to the total for the full 46 day period as far as
the relation of one soil to another was concerned. The next two
experiments were therefore limited to 7 days each. The samples

818

Connecticut Experiment Station Bulletin 342

consisted primarily of litter only, although several F layers were
included.

Preparation was carried out as already described. Titration was
made,, every day excepting the sixth. The results are shown in
Tables 31 and 32.

364
NUMBER

Figure 86. Relation of ammonia nitrogen content after a three-month
incubation to other soil properties. Humus type profile, H layers only.

The greatest evolution occurred the second or third day. Ob-
serve that the initial evolution and also the total evolution is greater
than it was in the first experiment. This is due to the fact that
the samples in the second and third experiments were previously
air/ dried. It is easily demonstrated that drying greatly stimulates
the decomposition that occurs following moistening.

Biological Studies

819

Other Experiments

In February, 1931, a number of samples were incubated at 28°
and the CO* measured on the fourth, fifth, seventh, and tenth days.
Through an error the bottles were first plugged with cotton, which
resulted in such complete diffusion that practically no CO2 accumu-

Table 31. Organic Matter Decomposition as Measured by Evolution

of Carbon Dioxide. (Samples Previously Air Dried.) Mgms. of

CO,, Average per Period

Profile

9

11

11

22a

26

28

No.

Podzol

R. H.

R. H.

Mull

Mull

Mull

Soil No.

180

305

3061

176

178

309

Days

1

59

41

79

48

53

39

2

124

131

102

123

105

110

3

124

196

88

122

94

112

4

97

177

73

100

70

89

5

75

143

64

76

55

62

7

62

113

64

66

45

46

Accumulated

540

806

470

535

418

457

Total

*F layer; all others litter.

Table 32. Organic Matter Decomposition as Measured by Evolution

of Carbon Dioxide. (Samples Previously Air Dried.) Mgms. of

C02, Average per Period.

Profile
No.

10

Mod. Podzol

16
Humus

17
Humus

27
Mull

29
Mull

30
Mull

Soil No.

379

317

3671

377

313

315

Days
1

2
3

70

83

65

90

130

81

55
92
66

41

85

98

66
160

181

114

158
91

4

47

56

45

73

128

64

5

38

45

33

53

95

51

7

39

46

42

47

83

47

Accumulated
Total

332

448

333

398

715

525

JF layer; all others litter.

lated. After the third day the bottles were kept stoppered except
during the hour of incubation.

In addition to the foregoing, CO2 was measured after one month
and three months on some samples set to incubate in a nitrogen
transformation experiment previously described. At the periods
stated a vial containing standard KOH was suspended in each

820

Connecticut Experiment Station Bulletin 342

bottle of soil for three days (with one interruption). The results
of both of the above tests calculated on a relative basis are given
in Table 33.

Table 33

C02 Evolution, Relative Values1

Mgms. CC

2

Profile
No.

Soil No.

Horizon

4th
Day

7th-10th
Day

Total 4th-
10th Days

1 Month

3 Months

13

S358
S359
S360

F
H

A2

100
31
IS

100
23
14

100
29

17

100

23

8

100

40

4

22a

S362
S363

F

A,

88

156

140

112
11

121

7

31

419
420
421
422

Lit.
F
H

A2

102

16

113
178

55

123
160

54

128
24
18

98

19
13

12

426

427
428
429

Lit.
F
H

A2

110

127

53

125
142

57

135

150

58

116

55
9

91

74

0

11

305

Lit.

220

205

224

—

—

—

Lake
Chambe

F
rlain

120

138

140

—

—

lValues based on organic carbon content of original samples.

Table 34. C02 Evolution, Relative Values on Treated Soils

Profile

No.

Soil No.

Horizon

Treatment

1 Month

3 Months

13

S358

F

o

100

100

L

78

77

N

113

89

NPK

108

85

LNPK

84

71

S359

H

O

25

62

N

23

54

NPK

24

53

LNPK

32

59

S360

A2

O

3.3

8

N

6.6

8

NPK

5.9

8

LNPK

17

8

22a

S362

Lit.

O

112

121

N

124

108

NPK

126

104

LNPK

119

123

Biological Studies

821

Effect of Treatment

Carbon dioxide was measured after one month and three months
on the samples treated with fertilizers and described under the
section on nitrogen transformation, page 807. These results are
presented as relative values in Table 34. No allowance has been
made for the CO2 coming from the lime (CaC03) itself. Appar-
ently lime has not been particularly stimulating to decomposition
when used either alone or in conjunction with a complete fertilizer.
The beneficial effect of nitrogen at one month has disappeared at
three months.

Natural Moist Condition versus Previous Drying

Finally, measurements were made on CO2 evolution in the ex-
periment designed to determine the effect of air drying on nitrogen
transformation. Vials of KOH were suspended in the bottles of
soil and titrations were made at the end of 1, 2, 7, and 14 days
with the results given in Table 35. Here we see that the use of
lime has increased very markedly the CO2 evolved. Since these soils

Table 35. Effect of Previous Drying Upon the Evolution
of Carbon Dioxide

Horizon

Previous
condition

Treatment

Mgms. C02, average per day

Location

Nov. 24

1st day

Nov. 25
2d day

Dec. 1
7th day

Dec. 3-8

9th-
14th day

Total

Waterville,

H,

Dry

O

62

53

18

4.3

154

N. H.

Lime1

203

90

30

6.4

355

Wet

O

28

19

14

3.6

78

Lime

155

51

29

6.4

267

H2

Dry

O

32

21

8

1.2

67

Lime

176

48

13

2.4

249

Wet

O

10

4

3

0.9

22

Lime

204 . .

30

11

2.8

258

N. Cole-
brook

H

Dry

O -/■
Lime

.73
238

54
101

20
36

3.8
11.0

166

431

Wet

O

13

10

9

2.3

44

Lime

204

56

34

9.6

341

M g. CaCO which is equivalent to 440 Mgm. CO .

822 Connecticut Experiment Station Bulletin 342

are quite acid the bulk of the increase must be due to a decomposi-
tion of the lime itself. In every case previous drying resulted in
a very definite increase in rate of decomposition. This stimulation
of the dry samples drops off rapidly, however, and by the end of
two weeks has almost disappeared.

Correlations and Relationships

Efforts to find a correlation between decomposition and other
properties are somewhat disappointing. Without further discussion
it must be said that there is practically no correlation between CO2
and total nitrogen ; nor is there with the amount of nitrogen trans-
formed. With pH, total calcium, and exchangeable calcium the
correlation is contradictory, being direct in some cases and inverse
in others. Some correlation was observed between CO2 and car-
bon-nitrogen ratio, although it is far from perfect.

Reference to Table 31 shows that the litter from Meshomasic
Mountain (No. 305) decomposed far in excess of any of the other
samples in the experiment. It may or may not be significant that
within this particular group of samples No. 305 was most acid
in reaction, contained the lowest amount of total and exchangeable
calcium, and the greatest amount of soluble nitrogen.

On the other hand, sample 313 gave off the largest amount of
CO2 of the group in which it was included, but this sample was
second highest in total calcium and highest in exchangeable cal-
cium. Therefore we are hardly justified in placing too much sig-
nificance on the correlations mentioned in the case of No. 305.

In this connection we must turn to the work of Melin (31) who
found a parallelism between total nitrogen content and ratio of
decomposition within a given species (working with leaves from
various species) but "as regards leaves from different species,
there was no direct correlation between total N content and the
rate of the first decomposition."

Joffe (24) believes that the speed of decomposition and quantity
of organic matter are closely associated with the process of
podzolization and the resultant effect upon the soil profile.

We know from observation in the field that duff from mull
types breaks down more rapidly than does that from any of the
other types. (Shortly after this manuscript had gone to press, there
appeared a paper by L. G. Romell, "Mull and Duff as Biotic
Equilibria'^ (Soil Science 34: 161-188, 1932), in which he upheld
Muller's view that the decomposition of organic matter in duff
and mull types differed in kind but not in rate. The present author
made no measurements of CO2 of the soil in situ and cannot,
therefore, offer any evidence to substantiate or disclaim Romell's
thesis. In the light of his paper, however, the above sentence in the
text might be altered to read, "We know from observation in the

Distribution of Vegetation

823

field that duff (litter) on mull types disappears as a surface cover-
ing more quickly and completely than does that from any of the
other types.") In the laboratory studies some indication of this was
apparent but there was an insufficient number of samples to demon-
strate such results with absolute certainty.

DISTRIBUTION OF TREE SPECIES AND LESSER
VEGETATION BY PROFILE TYPES

In this work no attempt at a detailed frequency distribution
study of the vegetation was attempted. However, in Tables 36
and 37 the vegetation is listed by profile types. It is seen that some

Table 36. Distribution of Tree Species

Pod

:ol

Species

All humus

Mull

N. H.

Conn.

types

Ash, white

—

—

—

5

Aspen

—

—

1

—

Aspen, large tooth

—

—

1

—

Basswood

—

—

—

2

Beech

2

1

2

3

Blue beech

—

—

—

1

Birch, black

—

2

2

2

Birch, gray

—

1

2

—

Birch, paper

1

1

—

—

Birch, yellow

5

1

—

1

Butternut

—

—

1

—

Cherry, wild black

—

—

1

—

Cherry, fire

1

—

—

—

Chestnut

—

1

—

—

Dogwood, tall

—

—

1

1

Fir, balsam

2

—

—

—

Hickory, pignut

—

—

—

2

Hickory, bitternut

—

—

—

3

Hickory, shagbark

—

1

—

3

Hickory, mockernut

—

—

1

—

Hemlock

1

2

3

1

Hop hornbeam, American

—

—

—

3

Maple, mountain

1

—

—

—

Maple, red

4

2

2

—

Maple, sugar

1

1

1

7

Maple, striped

1

—

—

1

Oak, black

—

2

3

6

Oak, chestnut

—

3

—

1

Oak, red

—

2

1

6

Oak, scarlet

—

2

3

2

Oak, white

—

2

3

7

Pine, red

—

—

2

2

Pine, white

—

1

2

—

Sassafras

—

—

—

1

Spruce, red

3

—

—

1

Tulip-tree

—

—

—

1

Witch-hazel

—

—

1

—

824

Connecticut Experiment Station Bulletin 342

Table 37. Distribution of Shrubs and Other Vegetation

Podzol

Species

All humus

Mull

N. H.

Conn.

types

Adder's tongue

1

Arrow-wood

—

—

1

4

Aster

2

—

3

Bittersweet

—

—

1

Blueberry, low bush

—

2

2

3

Blueberry, high bush

—

—

1

1

Chokeberry

—

—

1

—

Clintonia

3

—

—

1

Dewberry

—

—

—

1

Dogwood

—

—

—

4

Elder, red-berried

1

Fern, brake

—

1

1

3

Fern, Christmas

—

1

Fern, grape

—

—

—

1

Golden rod

—

—

1

Goldthread

1

—

Grasses

—

—

1

4

Greenbrier

—

—

1

Ground pine

—

—

2

—

Hazelnut

—

1

1

i_

Herbs

—

—

3

Hobblebush

4

1

Huckleberry

—

—

2

2

Indian cucumber

1

—

—

Laurel, mountain

—

1

2

Male-berry

—

—

1

Mayflower, Canada

2

—

1

1

Moss

2

—

2

1

Moss, shining club

1

—

—

Partridgeberry

—

1

1

3

Plantain, rattlesnake

—

1

Pogonia, whorl

—

1

Raspberry

1

—

Sarsaparilla

—

—

1

Shadbush

—

1

2

Sheep sorrel

—

—

1

—

Smilax

—

1

Star flower

1

"

Sweet pepperbush

—

1

_

Trillium, painted

2

Twisted stalk

—

■

Viburnum, toothed

Violet

Wintergreen

—

1

Wintergreen, spotted

—

Woodbine

Woodfern, spring

3

Wood sorrel

4

—

—

Discussion 825

of the trees such as hemlock, red maple and beech are to be found
in all locations. The oaks, hickories, and ash are not present in
the strongly podzolized region, but are quite abundant in Southern
New England. Of the oaks, the scarlet and chestnut are quite apt
to be associated with the raw humus and moderately podzolized
groups, while the white, red, and black oaks are associated with the
mull types.

In the case of the shrubs and other lesser vegetation the data
are not sufficiently complete to permit the drawing of any definite
conclusions. Hobblebush and wood sorrel appear to be more
abundant in the northern region, while arrow-wood and dogwood
seem to be confined to the mull groups in Connecticut.

DISCUSSION

Properties of Podzol and Mull Soils

Our investigations have indicated that podzolized soils of New
England are characterized by a moderately thick F layer that
weighs about 22,000 pounds per acre inch, and a thick humus,
usually raw, felty or greasy in texture, that weighs about 50,000
pound per acre inch. Frequently the Ai horizon is either entirely
lacking or is present only as a very thin layer. A2, the leached
layer, being mostly silica, has a volume weight of from 1.1 to 1.4,
while that of Bi is always less, usually 0.8 or 0.9. In B2 there is
an increase that continues into the d, being about 1.5 in the latter.
These differences are more closely associated with the organic
matter than they are with colloidal content, although silt plus clay
is generally somewhat low in A2 and rather high in Bi. Clay alone
exhibits on the whole even less variation in this respect than does
silt plus clay.

Similar studies on the mull types reveal a thickness and weight
of the F not dissimilar to what was found in the podzols, but the
H layer is lacking. The volume weight is lowest in Ai (about 0.8)
and increases regularly with depth, being in the C horizon practical-
ly identical to the corresponding horizon of podzol.

Silt plus clay and clay alone tend to be higher in the Bi than in
the horizons either above or below Bi. Volume weight is closely
associated with carbon content, as was true in the podzols.

Color. The color of New England soils is influenced very
considerably by the parent rock material, particularly in the red
sandstone region where all of the soils are red or purplish red.
Podzolization, of course, modifies the colors of the A and B
horizons, resulting in a gray A2 and usually a very dark reddish
brown (coffee brown) Bi. B2 may be of the same color as Bi or
it may be more yellowish than Bi. In the red sandstone region the
whole profile, even though podzolized, may possess a purplish hue.

826 Connecticut Experiment Station Bulletin 342

Chemical relations. Chemically the podzol profile differs
from the mull type in possessing a greater acidity in all but the C
horizons, a definite leached layer high in silica and low in iron,
aluminum, organic matter, nitrogen, and calcium content and very
low in buffer capacity ; and a B horizon relatively low in silica and
high in the other constituents. In the mulls, this accumulation in
the B is not present or, in any event, only to a very slight degree.

The properties of the humus types lie intermediate between
those of the podzol and the mull types.

Biological relations. Nitrogen transformation in the duff
of forest soils is dependent upon the properties of the material
itself rather than upon the type of profile with which it was
associated. Variations within a type are as great or greater than
differences between types, other conditions being equal. In other
words the type of profile is in indirect rather than direct control of
the biological processes.

Decomposition of the duff from the mull types appeared to be
more rapid than that from the humus and podzol types. Evidence
of this is greater and more convincing in the forest than it is in
the laboratory. Dissimilarity in environmental conditions exert
an influence in the field that is not obtained in the laboratory under
uniform conditions. Light, temperature, wind movement, nature
of the underlying soil, activity of earthworms, and other macro-
scopic organisms are apt to be sufficiently different to exert an
effect not obtained in an artificial environment. Therefore one is
not justified in applying to the field, without caution, results on
decomposition obtained in the laboratory.

Profile Development

In a pedological sense, all of the soils of New England are
relatively young. Zones of eluviation and illuviation are not well
defined in the majority of agricultural soils and forested soils of
the mull type. This is shown not only in the data in the latter
part of Tables 3 and 7 but also in the study of seven profiles from
Connecticut mixed hardwood stands given in Bulletin 330 of this
Station (20, p. 687). Studies at the Harvard Forest in Massachu-
setts (15) lead to similar conclusions.

Under certain conditions, notably where older hemlock or white
pine are growing and where other factors are suitable, this soil
forming process is accentuated and greatly hastened, which results
in a mature soil or one approaching that condition. The relative
coarseness of the soil aids this process through rapid leaching.
Here we find some concentration of silt and clay in the B horizon,
but the principal movement is confined to the iron, aluminum,
organic matter and calcium. So long as the present stand of timber

Discussion 827

exists or is replaced by a similar stand, the soil profile will retain
its mature characteristics. A radical change in forest type or treat-
ment or a full clearing of the land and devoting it to agricultural
uses would alter the soil profile and very probably cause a tendency
towards the mull type.

Tourney states (46) that: "Each stage in succession is ac-
companied by a corresponding change in the environmental com-
plex but primarily in the soil. It is this change in the soil that
makes possible the next stage in succession .... So long as
succession takes place change in the soil takes place. So long as
change in the soil takes place there must be corresponding change
in the vegetation. . . . There is no climax in vegetation except
when the soil weathering processes are complete and the soil is
fully developed. There is no succession except when the soil
weathering processes are in progress and the soil not fully
developed."

This appears to be sound reasoning, yet does it not credit to the
vegetation a degree of sensitivity to soil properties greater than
that which actually exists ? A change in vegetation probably always
brings about a change in soil — certainly it does in some cases —
but does it necessarily follow that a change in vegetation is de-
pendent upon a change in the soil (exclusive of fire and the
activities of man) ?

Tamm (44) states that according to the Russian point of view
if a steppe vegetation gave way to a forest type of vegetation,
the soil would gradually but very slowly change. The new soil type
would retain some of the characteristics of its former character
for a long time. He says, ". . . . the conversion which takes place
in the soil after the change of the vegetation goes much slower
than the change of the forest vegetation itself."

It may be well to include Coffey's (9) statement on the subject.
"There is no doubt that a change in native vegetation is usually
indicative of a change in soils, but there are striking exceptions.
In many instances where there is a marked difference in the natural
timber growth it is possible to find differences in the soils to explain
it, but in other instances markedly different soils will show the
same character of timber growth. ... A fundamental essential
of scientific classification is that it must be based upon inherent
and invariable properties of the materials classified. Classifying
soils according to native vegetation is therefore going at the matter
backwards; it is putting the effect before the cause. It is better
to determine the cause of the change in vegetative covering, and, if
found to be due to a variation in the soil, base the classification
upon this ; otherwise the destruction of the vegetation will destroy
the foundation of the system."

The system of soil classification followed is in harmony with
the foregoing quotation. We describe the properties of the various

828 Connecticut Experiment Station Bulletin 342

soils as they are found irrespective of the vegetation, but our chief
aim is to attempt a correlation of soil properties and environmental
factors associated with various forest types.

With respect to cultivation of a former podzol forest soil, Tamm
(43) states that in the north country one frequently sees clumps
and streaks of bleached soil and orterde in a cultivated field,
indicating the marked resistance it is offering to the loss of its
original characteristics. A similar thing has been observed in New
Hampshire, and in at least two localities in Connecticut.

Period of Time Required to Podzolize a Soil

Observations in Sweden by Tamm (43) indicate that in a young
soil under Scotch pine one to two cm. of leached soil are formed
in about 100 years. Podzolization develops at a much slower rate
in moss heath with thin raw humus than in forests rich in raw
humus and moss. Observations by Griffith, Hartwell and Shaw
(15) led them to believe that a leached horizon appeared under
white pine after about 60 years, and at 80 years the upper margin
of the B2 had risen from a 9 inch depth to about 1 inch. Upon
cutting the white pine and allowing hardwood to come in, the level
of the B2 gradually lowers again. One must bear in mind that these
measurements were made simultaneously on stands of various ages
occurring on soils presumed to be uniform originally. The changes
just described unquestionably do occur, and, in this country at
least, the method used by these investigators is the only one at our
disposal at the present time.

The foregoing studies together with our own observations lead
us to conclude, therefore, that where podzolization occurs in
Connecticut it is a slow process and has not been formed by one
generation of trees.

Altitude

Although the altitude in this State varies from sea level to 2355
feet the variation is not sufficiently great to be a main controlling
factor. In the higher altitude one is more apt to find podzolization,
but other factors such as forest species and soil have a greater
influence than altitude has.

On the other hand, in New Hampshire latitude and altitude
directly and indirectly are the most contributory factors in effecting
podzolization.

Relation of Forest Type and Soil Properties

Studies similar to those of Cajander (8) if carried out in New
England would not yield the fruitful results that he obtained in
Finland and Central Europe. In New England we have many more

Summary 829

species with which to deal and the forests are in most cases much
more heterogeneous in composition. Associations of tree and
ground cover are not nearly so well denned. The factors involved
that bring about this heterogeneity may be assigned partly to
climate and partly to the activities of man through his repeated
cutting of the timber, in many cases before it had been allowed to
reach a profitable size for lumber.

Nevertheless we do find some correlations. Raw humus, and
humus approaching such a condition, is generally more apt to be
found on poor droughty soils such as the Gloucester series, and
particularly on the hill tops and knolls.

Podzols in Connecticut are more likely to be found under hem-
lock. Even in hemlock-hardwood mixtures, the podzol may be
confined to a local area immediately below the hemlock tree. In
fact podzol in this State occurs in most cases only in very localized
areas, confined to one or two trees, or mere patches beneath a few
individual trees. It is always restricted to the immediate forest or
woodlot. Perhaps the most uniform distribution and largest area
in Connecticut is the large burn at the Eastford — Pomf ret location
(profile No. 9), although even here it varies considerably in
thickness.

Mull is much more common than is podzol as would be expected
from a consideration of climate and forest species which occur
here. Under certain conditions the mull is more fully developed
than in others. It is quite evident that the controlling factors are
soil and topography, the latter greatly influencing the moisture
relations and hence the stand. A good mull is found under a thrifty
hardwood stand, and the stand is there because of the favorable
soil. On poor soils only the more hardy species such as pitch pine,
scarlet oak, and chestnut oak survive. Under these conditions, due
both to species and soil, a raw humus develops.

As one goes north podzol becomes more common until in the
White Mountain region podzol is the rule. There mull is to be
found only in woodlots or other favorable localities where moisture
conditions are favorable and the soil quite fertile.

SUMMARY

The data presented in this bulletin were obtained in a study
of soite in the_ forests of Connecticut and New Hampshire.
Connecticut lies in the transition zone between the gray brown soils
to the south and west and the definitely podzolized soils to the
north. New Hampshire is located at the southern portion of the
latter group.

The forests from which these soils were taken included pure
hardwoods, hemlock-hardwoods, pine plantations, spruce hard-
woods and nearly pure spruce.

830 Connecticut Experiment Station Bulletin 342

For this study profiles were grouped into the following types:,
Podzol, Raw Humus, Humus, Mild Humus, and Mull.

The weight of the F layer varied from 9200 to 28,000 pounds
per acre inch, and averaged 19,800 pounds, while the H layers
varied from 35,800 to 107,700 pounds and averaged 53,100 pounds
per acre inch. There was very little difference in the weight per acre
inch between Connecticut and New Hampshire profiles, altho
the total amount was greater in the latter.

A soil density of 1.0 or less (water ^1.0) was found in the
case of the Ai horizon of the mulls and Bi horizon of the podzol
profiles. Below Bi the density always increased with depth. All
orstein samples possessed a high volume weight.

Volume weight was correlated more closely with organic matter
content than with clay content or any other physical property
studied. The deposition of organic matter in the B horizon of
podzol soils causes quite a marked reduction in the total weight
per acre of the soil to a depth of 24 inches.

All of the soils are quite acid, with the H layer, where present,
being the most acid portion of the profile. The upper horizons of
the podzol and raw humus types are definitely more acid than the
corresponding horizons of the mild humus and mull types.

Differences between the podzol and non-podzolized profiles are
most strikingly shown in the distribution of iron, aluminum, nitro-
gen and organic carbon in the two types.

Based upon the analyses, the podzol types in New England are
of the iron-humus type with no distinct separation of the iron
from the humus. This is in distinction from the podzols of the
Scandinavian countries which are usually either iron or humus
podzols or the iron-humus type in which most of the iron is in a
layer separate from the humus.

Forest soils are characterized by a wide C - N ratio.

Calcium is not concentrated in the B horizons as is the iron,
but is more or less diffused throughout the whole lower profile.
New England soils appear to be more deficient in lime than are
the soils of Sweden reported by Tamm.

Although the percentage composition of calcium in the duff is
high, on an acre basis it is quite insignificant in amount when
compared with that in the lower mineral horizons.

The proportion of calcium in the exchangeable form is high
(30-75 per cent) in the duff layers, and low (less than 5 per cent)
in the B and C. On the whole the proportion is much less in forest
soils than it is in good agricultural soils.

Magnesium equals or exceeds the calcium in amount present.

Summary 831

Exchangeable hydrogen is highest in the H and Bi layers of
the podzols, and is closely associated with the organic matter
content. j $.j£i

Soluble phosphorus and exchangeable potassium are very largely
confined to the organic portions of the profile.

Ammonification occurred in practically all samples, but nitrifica-
tion was generally very poor. The addition of lime caused the
formation of nitrates at the expense of ammonia. Nitrogen trans-
formation was greater in the F layer than in the H or Ai horizons
as a rule. Inoculation had but little effect, which indicated that if
any stimulating or inhibiting substances exist in the inoculating
material they are not extracted with water.

Where treatments were used some benefit was observed. In no
case did all of the added bloodmeal nitrify. Samples possessing
a very wide C-N ratio required a large amount of nitrogen to
permit the accumulation of ammonia or nitrates.

A positive correlation exists between nitrogen transformation
and pH, C-N ratio, calcium and in some cases total nitrogen.

As would be expected the more completely the organic portion
of the forest soil profile is decomposed the less CO* is evolved.
Evolution is most rapid during the first few days ; after this period
it rapidly falls off to a low level, which persists for a long period.

Air drying a soil before incubation had no effect on nitrogen
transformation except to increase slightly ammonia formation.
Such treatment is, however, stimulating to the initial evolution
of CO*.

Practically no correlation was found between the rapidity of
decomposition and chemical properties of the soil.

Some correlation between tree species and type of soil profile is
apparent, but only to a limited degree. In the case of the lesser
vegetation such a relation is even less evident.

The type of profile that develops in the forests of Southern
New England appears to be controlled to a large extent by the
soil and related environmental factors and only indirectly by the
vegetation growing thereon. Podzolization is a slow process and is
not brought about within one generation of trees.

Podzolization in the forest soils of the mountainous sections of
New Hampshire is the rule rather than the exception and results
from a combination of factors, the greatest being climate and soil.
Assuming that it would be possible to produce and maintain a good
mull condition and still retain the forest type now present, would
or would not the tree growth be favored? Presumably it would.
Such a question at the present time is largely an academic one.

832

Connecticut Experiment Station Bulletin 342

PLANT SPECIES MENTIONED1

Common Name

Ash, white

Aspen

Aspen, large toothed

Basswood

Beech

Beech, blue

Birch, black

Birch, gray

Birch, paper

Birch, yellow

Butternut

Cherry, wild black

Cherry, fire

Chestnut

Dogwood, tall

Fir, balsam

Hickory, pignut

Hickory, bitternut

Hickory, shagbark

Hickory, mockernut

Hemlock

Hop hornbeam, American

Maple, mountain

Maple, red

Maple, sugar

Maple, striped

Oak, black

Oak, chestnut

Oak, red

Oak, scarlet

Oak, white

Pine, pitch

Pine, red

Pine, white

Sassafras

Spruce, red

Tulip-tree

Witch-hazel

Trees

Scientific Name

Fraxinus americana
Populus tremuloidcs
Populns grandidentata
Tilia americana
Fagus grandifolia
Car pinus caroliniana
Be tula lenta
Be tula populifolia
Betula alba papyrifera
Betula lutea
Juglans cinerea
Primus serotina
Prunus pennsylvanica
Castanea dent at a
Cornus florida
Abies balsamea
Carya glabra
Carya cordiformis
Carya ovata
Carya alba
Tsuga canadensis
Ostrya virginiana
Acer spicatum
Acer rubrum
Acer saccharum
Acer pennsylvanicum
Quercus velutina
Quercus prinus
Quercus rubra
Quercus coccinea
Quercus alba
Pinus rigida
Pinus resinosa
Pinus strobus
Sassafras variifolium
Pice a rubra
Liriodendron tulipifcra
Hamame lis virginiana

Shrubs and Other Lesser Vegetation

Adders tongue

Arrow-wood

Aster

Bittersweet

Blueberry, low bush

Blueberry, high bush

Chokeberry

Clintonia

Dewberry

Dogwood

Erytlironium americanum

Viburnum acerifolium

Aster sp.

Celastrus scandens

Vaccinium vacillans or pennsylvanicum

Vaccinium corymbosnm

Pyrus arbutifolia

Clintonia borealis

Rubus hispidus

Corn-us sp.

'Checked according to Gray's Manual, Seventh Edition.

Plant Species Mentioned

833

Common Name

Elder, red-berried
Fern, brake
Fern, Christmas
Fern, grape
Goldenrod
Goldthread
Grasses
Greenbrier
Ground pine
Hazelnut
Hobblebush
Huckleberry
Indian cucumber
Laurel, mountain
Male-berry
Mayflower, Canada
Moss, club
Partridgeberry
Plantain, rattlesnake
Pogonia, whorl
Raspberry
Sarsaparilla
Shadbush
Sheep sorrel
Smilax
Star flower
Sweet pepperbush
Trillium, painted
Twisted stalk
Viburnum, toothed
Violet

Wintergreen
Wintergreen, spotted
Woodbine
Woodfern, spring
Wood sorrel

Scientific Name

Sambuscus racemosa
Pier is aquilina
Polyslichimi acrosticho ides
Botrychium sp.
Soli-dago sp.
Coptis trifolia
Gramineae
Smilax rotundi folia
Lycopodium complanatum
Corylus sp.
Viburnum ahiifolium
Gaylussacia baccata
Medeola virginiana
Kalmia latifolia
Lyonia ligustrina
Maianthemum canadense
Lycopodium sp.
Mitchella repens
Epipactis sp.
Pogonia verticellata
Rubus idaeus
Aralia nudicaulis
Am-elanchier canadensis
Rumus acetosella
Smilax sp.
Trent alis americana
Clethra alnifolia
Trillium undulatum
Streptopus sp.
Viburnum dent a turn
Viola incongnita
Gaultheria procumbens
Chimaphila maculata
Psedera quinquefolia
Aspidium spinulosum
Oxalis acetosella

Acknowledgment

The writer is greatly indebted to M. F. Morgan, Agrono-
mist, for his guidance and helpful criticism throughout the
work ; to Henry Hicock, Assistant Forester, for assistance in
locating stands and identifying vegetation ; to Raymond Kien-
holz, Plant Physiologist, for reviewing and criticizing the
manuscript; and to Dwight B. Downs for assistance in the
field and laboratory work.

834 Connecticut Experiment Station Bulletin 342

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