GIFT OF

Aerie. Dent.

/-"''^ ~ Issued August 12, 1911.

U. S. DEPARTMENT OF AGRICULTURE,

BUREAU OF SOILS— CIRCULAR No. 35.

MILTON WHITNEY, Chief of Bureau.

SOILS OF THE EASTERN UNITED STATES AND THEIR USE— XIIL

THE MEMPHIS SILT LOAM.

BY

JAY A. BONSTEEL,

Scientist in Soil Survey.

WASHINGTON:

GOVERNMKNT PRINTING OFFICE.
1911.

BUREAU OF SOILS.

MILTON WHITNEY, Chief of Bureau.
ALBERT G. RICE, Chief Clerk.

SCIENTIFIC STAFF.

FRANK K. CAMERON, In charge of Physical and Chemical Investigations.

CURTIS F. MARBUT, in charge of Soil Survey.

OSWALD SCHREINER, in charge of Fertility Investigations.

2

SOILS OF THE EASTERN UNITED STATES AND THEIR USE— XIII.

THE MEMPHIS SILT LOAM.

GEOGRAPHICAL DISTRIBUTION.

The Memphis silt loam consists of finely divided silty material,
known as the loess, which had its origin in the more northern por-
tion of the central States in conjunction with the glacial invasion
of that section. Unlike the other soil types derived from the loess,
however, the Memphis silt loam is derived from those deposits that
extend southward from the confluence of the Missouri and the
Mississippi Rivers almost to the margin of the Gulf of Mexico.
In this respect it is unique among loess-derived soil types. This
material, originated in connection with the glaciation of the North
Central States, was carried southward by the waters resulting from
the melting ice, and distributed along the drainage ways through
the Mississippi Valley. Thence, it is supposed that a considerable
proportion of the material has been reworked and redistributed,
through wind action, being deposited principally upon the eastern
side of the Mississippi River, from the vicinity of St. Louis, Mo.,
southward to Baton Rouge, La. It thus comprises a long nar-
row belt along both sides of the Mississippi River in southern Illi-
nois and eastern Missouri, covering a considerable proportion of
the upland in western Kentucky, a belt 50 to 70 miles broad in
western Tennessee, a continuous belt, varying from 50 miles in width
in northern Mississippi to a narrow strip, 15 to 20 miles broad, where
it passes across the southern line of Mississippi into eastern Louisiana
and terminates between Baton Rouge and New Orleans. It also
occurs covering a considerable territory on the west side of the
Mississippi in northeastern Arkansas.

Throughout its entire extent this characteristic glacial silt was
carried far southward by water action, from a truly glaciated region,
and distributed by the action of both wind and water principally
over the uplands to the east of the Mississippi River. It covers the
various Coastal Plain formations and, in its more northern portion,
even the consolidated rocks of the outward edge of the Ozark uplift.

The Memphis silt loam has been mapped to the extent of
1,863,290 acres. It has been encountered in 12 separate areas in 6

different States.

3

4 SOILS OF THE EASTERN UNITED STATES.

CHARACTERISTICS OF SOIL AND SUBSOIL.

The surface soil of the Memphis silt loam in its characteristic de-
velopment is a brown or brownish-yellow silt loam, containing nearly
80 per cent of silt and 15 to 20 per cent of clay, with very small
amounts of coarser material, although a little very fine sand is not in-
frequently present. The depth of this surface soil varies materially
in the different parts of any area where it may be developed. Upon
all the steeper and more hilly portions of the type the surface cover-
ing is from 2 to 4 or 5 inches thick, while upon the more level areas,
where erosion has not been so active, the surface brown loam may
attain a depth of 8 to 15 inches. It grades downward into a choco-
late-brown to yellow silt loam, which is a little more stiff and com-
pact than the surface soil, through the presence of a slightly higher
content of clay.

This material usually extends to a depth of 3 feet or more, and in
the majority of cases rests directly upon the soft but compact yellow
silt, sometimes mottled with gray, which constitutes the characteristic
section of the loess wherever it is fully developed. In other instances,
and particularly near the eastern margins where the total thickness
of the loess dwindles to 3 or 4 feet, the deep subsoil may be somewhat
modified by the presence of small amounts of medium to coarse sand,
with occasional pebbles and noncontinuous bands of gravel. In such
instances the entire section is liable to be distinguished by a brown
or chocolate color. In the less eroded areas where weathering has
proceeded uninterruptedly to greater depths, the subsoil is reddish-
yellow to a deep chocolate brown. In such instances it is frequently
somewhat more stiff and clayey through the breaking down of the silt
particles and may locally be known as yellow or red " clay," depend-
ing upon the prevalent color tone.

The Memphis silt loam is usually sharply contrasted with all of
the soils in the region where it occurs. In the first place, it is the
one great silty soil which extends from southern Illinois southward
through the Coastal Plain region to the Gulf of Mexico, being con-
trasted with the more sandy or more clayey soils derived from other
formations in the general region. It is widely known by a number
of popular terms, such as the " brown loam " or the soil of the " Cane
Hills " and " Flat Hills " regions where it occurs.

It has been found desirable in all of the more recent surveys to
separate this material on the basis of the topography and prevalence
or absence of erosion into two soil types. Of these the more eroded,
or the rolling and hilly section commonly found in the " Cane Hills *'
district, constitutes the characteristic Memphis silt loam, while the
less eroded brown loam of the " Flat Hills " section has in several
instances been mapped as the Richland silt loam. The erosion fea-

_

THE MEMPHIS SILT LOAM. 5

tures and the consequent topography, together with their resultant
effects upon agriculture, constitute the fundamental basis for this
separation. The materials are practically the same, except that in
the case of the Richland silt loam the surface brown silty loam
material normally extends to a depth of 10 or 15 inches, while in the
case of the typical Memphis silt loam it has a depth varying from 2
to 12 inches.

Along the eastern margin of the region in which this silty material
is developed, where the total depth of the loess is less than 3 feet, the
presence of the red or reddish-yellow sands and gravels of an older
formation gives rise to a type of soil known as the Lexington silt
loam, distinguished by the presence of this sand and gravel in the
deeper subsoil.

SURFACE FEATURES AND DRAINAGE.

The usual topography of the typical Memphis silt loam is rolling
to hilly. The type occurs along the rivers. At places more remote
from the bluff-line the surface becomes slightly rolling to undulating,
and in all of the more remote upland occurrences of the type there
are considerable areas of practically flat land, which in the later
classification will probably be classed as the Richland silt loam, be-
cause of this topographic difference.

The Memphis silt loam follows the bluff-lines bordering the Mis-
sissippi drainage in Missouri, southern Illinois, and in western Ken-
tucky, Tennessee, and Mississippi. This bluff rises to an altitude
of 150 to 250 feet above the adjoining bottom lands or above the
waters of the river itself, which frequently wash the foot of the
bluff. For a considerable distance back from the bluff-line the front
of the escarpment is broken at frequent intervals by deep V-shaped
valleys, through which the short tributary streams flow down to
the main drainage courses of the bottom land. At greater intervals
the larger streams have cut broad valleys through the soft loessial
deposit or have formed basins and amphitheaters that open out into
the Mississippi bottoms. Away from the crest of the escarpment
the surface of the country consists of sharp ridges and cross ridges
separated from one another by narrow, steep-sided valleys. The
crests of these ridges are frequently level and are occupied by tilled
fields. They become broader as one passes away from the bluff-line
until they merge into the level plateau of the more remote upland,
covered principally by the Richland silt loam. All of the minor
streams which flow into the larger tributaries or directly down to the
Mississippi itself have cut back rapidly into the soft, unconsolidated
materials of the Memphis silt loam, giving rise to a network of
minor stream channels and gullies, spreading out like the branches
of a tree. With every heavy rainstorm each of these valleys or

6 SOILS OF THE EASTERN UNITED STATES.

gulleys cuts deeper into the loess material and removes more and
more soft earth from the upland areas. As a result the originally
level plateau has been carved into rough and hilly topography along
the bluffs and throughout the region where this material and this
topography have been developed. From the mouth of the Ohio
southward this section is commonly known as the " Cane Hills."

The surface of the Memphis silt loam attains to elevations of 500
feet or more in eastern Missouri and in southern Illinois, where it
mantles the uplands as well as follows the bluffs of the Mississippi
and its major tributaries. The surface of the type gradually de-
scends southward ; it occurs at altitudes of 300 to 350 feet above tide
in western Kentucky and western Tennessee and the extreme north-
ern portion of Mississippi; thence it gradually slopes southward to
an altitude of about 100 feet above sea level at the Mississippi-Louisi-
ana line and descends to an altitude of less than 50 feet between
Baton Rouge and Xew Orleans.

Similarly, the bluffs separating the upland from the great alluvial
bottoms are higher and more eroded in the more northern portion,
rising not infrequently 250 feet above the adjoining alluvial bottoms
in western Tennessee and northern Mississippi. Farther south these
bluffs rise from 15 to 50 feet above the river, and south of New Or-
leans constitute only a low, bounding ridge to the east of the alluvial
delta lands. The smaller ridges to the west of the Mississippi River,
particularly in Arkansas and in northern Louisiana, rise to alti-
tudes of only 15 to 35 feet above the bottom lands by which they are
usually surrounded. Thus there is a considerable difference both in
absolute elevation above tide level and in the relative elevation above
adjoining low lands through the wide extent of territory covered
chiefly by the Memphis silt loam.

The natural drainage of the type is quite complete along the bluff
lines and in close proximity to the larger drainage ways and there is
practically no difficulty encountered through excess of moisture. In
the smoother country somewhat remote from the streams, and par-
ticularly in the "Flat Hills" region, latterly mapped as the Rich-
land silt loam, there are considerable level areas and even minor
depressions where the natural drainage of the Memphis silt loam
is deficient. Such areas are always marked by a light-gray to ashy-
white surface soil, except where the drainage is so obstructed that
local swampy areas have been formed and the shallow mucky accumu-
lation over the silty material gives a darker color to the surface soil.

In practically all instances of this kind there is a further pro-
nounced indication of deficient drainage through the presence of
small iron concretions, locally known as " iron buckshot " or " iron
gravel," to be found both in the surface soil and at a slight depth
below it, where the gravel is not infrequently accumulated as a layer

THE MEMPHIS SILT LOAM. 7

or band of partly compacted pebbly material. In all such instances,
also, the deeper subsoil is marked by a prevailingly light-gray color
only slightly mottled by yellow iron-stain along joints, crevices, and
root holes. The indications above mentioned are practically infalli-
ble in detecting poor drainage conditions in the areas of the Memphis
silt loam and its associated type, the Richland silt loam.

Erosion is by far the most important problem in connection with
the tillage of the Memphis silt loam. Owing to the soft, noncohesive
character of the materials, not only of the surface soil and subsoil,
but also of the underlying silt ; because of the elevated position of a
large proportion of the type above adjoining drainage ways and the
great alluvial bottoms; and because of an almost universal tendency
to produce the intertilled crops upon this type, particularly cotton,
through a long series of years, great difficulty has been experienced
in preventing erosion. In fact this soil may only be maintained
against ruinous washing in the vicinity of the bluffs by allowing a
large proportion of its surface to remain in the native forest growth
of post oak, scarlet oak, Spanish oak, hickory, beech, and tulip
poplar. Even the ordinary pasture grasses are not competent to
serve as effective soil-binders upon the steeper slopes near the edge of
the bluff. The bond formed by the grass roots and the surface vege-
tation is not infrequently undermined by the cutting back of the gul-
lies to such an extent that great masses of the surface soil fall into the
gullies beneath and are dissolved and carried away by the torrents,
resulting from heavy rainfalls. In the more gently sloping areas,
however, the covering of the native grasses, such as Bermuda, lespe-
deza, and crab grass, is competent to maintain the soil against
erosion. Each has a low habit of growth and each develops an intri-
cate root system well suited to soil-binding purposes. All of these
grasses have a value, not only for pasturage purposes, but also for the
cutting of hay, and would be more generally appreciated for these
uses except for the cotton farmers' universal objection to any form
of grassy growth within the areas of cultivated fields.

Upon the more level uplands, which are not threatened by the back-
ward cutting of gullies and the larger streams, the principal occupa-
tion of the type occurs. In such areas the surface water is usually
absorbed to a great degree by the deep surface soil, and erosion is not
serious. However, the areas possessing these gentle slopes occupy
but a small percentage of the total extent of the typical Memphis
silt loam, and these, particularly in the more southern localities, are
anually occupied to their full limit for the production of intertilled
crops like cotton and corn. Unless considerable care is taken in lay-
ing off the rows to form contours around the slopes, and unless in-
cipient gullies are immediately checked by the construction of brush
dams, erosion is liable each year to invade even these upland portions

8 SOILS OF THE EASTERN UNITED STATES.

of the type to such an extent as to destroy them for agricultural
purposes.

It is extremely fortunate under these circumstances of prevalent
excessive erosion that the subsoil materials and the parent loess are
capable of becoming transformed into fertile and productive soil
within a very brief period of time, provided proper care is taken to
plow the subsoil material thoroughly and to incorporate organic
matter for the formation of a complete soil. There are very few
soils in the United States, and practically none except those derived
from similar deposits of loess, which show such marked character-
istics of speedy recuperation from excessive erosion.

LIMITATIONS IN USE.

The principal limitation to the use of the Memphis silt loam for
the production of cultivated crops lies in the tendency toward exces-
sive erosion already mentioned. The type taken as a whole may only
be tilled to the extent of 15 to 20 per cent of its total surface area in
the " Cane Hill " regions, and to the extent of about 30 or 40 per cent
of its surface in the more gently undulating portions of its develop-
ment. The balance of the type must be left either in forest upon th<?
steeper slopes or covered with the native grasses upon the more gen-
tle slopes, not only for the protection of these slopes themselves, but
also to prevent the invasion of tilled areas through the formation of
gullies and of deep washes. This limitation, of course, applies only
to the area which may not be tilled and not to the portions where
crops may be grown.

Excessive erosion in many instances has also adversely affected the
depth and condition of the surface soil of the Memphis silt loam.
Although even in the most eroded areas a surface soil may be de-
veloped by proper cultural methods in two or three years time, there
are considerable areas where the requisite organic matter for the
formation of a complete surface soil is only present to a depth of
2 or 3 inches. In all such areas and even over a considerable pro-
portion of the tilled fields upon the Memphis silt loam the incorpora-
tion of organic matter is one of the prime necessities for the produc-
tion of adequate crop yields. In all areas where the type is found,
whether in the more northern grain-growing sections or in the moi
southern cotton-producing areas, the restoration of organic matter
to the Memphis silt loam constitutes an important problem for the
maintenance of the type under agricultural occupation.

The tillage difficulties encountered in the use of the type consist
chiefly in those resulting from a tendency toward erosion. The soil
itself is soft, friable, easily broken, and easily tilled. Drainage
a problem only to a limited extent over the flatter portions of the
type, and throughout its extent it is stone free, and not encumbered
by other obstructions to tillage except the gullies already mentioned.

THE MEMPHIS SILT LOAM. 9

The development of the type in a long, narrow belt extending from
the central United States almost to the Gulf of Mexico gives rise to
a wide variation in the climatic surroundings under which it is culti-
vated, and this factor of climatic influence modifies to a considerable
degree the crop adaptations of the soil in its different localities. In
the more northern regions the general farm crops, particularly corn,
winter wheat, oats, and grass, are well suited to the Memphis silt
loam. In the central regions, including Kentucky and western Ten-
nessee, tobacco is also grown to advantage, though to a very limited
extent, while cowpeas and even cotton are produced. From western
Tennessee southward the climatic surroundings are such that cotton
constitutes the principal money crop, and even corn is grown in sub-
ordinate acreage. With the exception of cowpeas for forage pur-
poses, and of local developments of market -gardening and trucking
crops, the more southern portions of the Memphis silt loam are de-
voted almost exclusively to the growing of cotton, with corn as a
supplementary crop.

IMPROVEMENT IN SOIL EFFICIENCY.

Protection from erosion is the prime necessity for the better devel-
opment of the Memphis silt loam. This may be accomplished in
a variety of ways, depending upon the declivity of surface slopes,
upon the amount and character of the annual rainfall, upon the
proximity of deep-cut drainage ways or of shallow stream valleys
and gullies, and to a considerable degree upon the selection of crops
made in the natural adjustment to climatic conditions. In the more
northern areas where the Memphis silt loam is developed, very little
attention to erosion problems is necessary beyond the production of
grass upon the more gentle slopes, and the occupation of the steeper
slopes by forest. Even the moderate slopes may be planted to
orchard fruits, provided a little care is taken to arrange the rows
according to the contours of the land. Such a use of this type has
been made to a considerable extent in one or two areas, and very
little difficulty from erosion has been experienced in such cases.
Farther south the adoption of contour farming, of terracing, of the
construction of brush dams to prevent the invasion of gullies upon
tilled land, the grassing of the steeper slopes, and the forestation of
declivities along the bluff are methods requisite for the prevention
of erosion.

On the more gently sloping surfaces deeper plowing to form an
absorptive reservoir for rain water, the careful construction of water
furrows to prevent the too rapid off-flow of excess water, and the
adoption of a crop rotation which shall leave the 'surf ace of the land
occupied by cover crops during the winter months and by grass cover
during a portion of the rotation are all desirable methods for main-
100241°— Cir. 35—11 2

10 SOILS OF THE EASTERN UNITED STATES.

taining the land under cultivation, and, while doing so, for prevent-
ing erosion.

Over a considerable proportion of the type from the Ohio River
southward the deeper plowing of the Memphis silt loam is essential
for the increase of crop yields. In the general practice of the region
plowing to a depth of 3 or 4 inches is considered adequate. In the
case of a silty and somewhat clayey soil like the Memphis silt loam,
deeper plowing is strongly to be recommended. Upon all of the more
level areas the heavy 2-horse or 2-mule hitch and the breaking plow
should be used in place of the light 1-horse hitch and the small turn
plow. The plowing should also be done " broadcast," as in the case
of the central prairie regions, instead of the usual method of plowing
out the previous rows and bedding up in the water furrows. The
thorough working of the surface soil to increase its depth to 12 or 15
inches will result in decidedly increased crop yields, whether of cotton
and corn or of the grain and grass crops.

Throughout a large part of the area where the Memphis silt
loam is found, the incorporation of additional organic matter is
decidedly essential. This should be accomplished either through the
production of a winter cover crop, which may be plowed under in
time for the production of a succeeding summer crop, or through the
growing of a leguminous crop like cowpeas, lespedeza, or bur clover.
These may be partialty grazed off or may even be cut, but they
leave all of the roots and a considerable part of the stubble to be
turned into the soil. Wherever it is possible it is recommended that
the green crop thus produced should be cut and fed to farm animals
rather than that it should be turned under in its full growth. A
greater value is secured from the crop and the restoration of organic
matter is nearly or quite as efficient.

It would be difficult or impossible to recommend any fertilizers or
classes of fertilizing material aside from organic matter which
would be efficient for use upon the Memphis silt loam under the
widely varying conditions of climate, of crop production, of drain-
age, and of erosion, which effect the type in the different areas of its
development. The adoption of proper methods of fertilization
should follow the lines developed by local experimentation as applied
not only to this soil type, but also to the kind of crop to be grown
upon it under the attendant climatic circumstances.

LIMITATIONS UPON SPECIAL CROPS.

In the more northern regions where the Memphis silt loam is de-
veloped it is well suited to the production of quite a number of gen-
eral farming crops, and also to orchard fruits. Its use for these pur-
poses will be described in the discussion of the crop adaptations of
the type. Farther south tobacco is also grown in the proper environ-

THE MEMPHIS SILT LOAM. 11

merit, and is a fairly successful crop. In the more southern extension
cotton is practically the dominant crop, and it has only been within
recent years that any diversification of agriculture has occurred, aside
from the growing of a limited area of corn for the feeding of work
stock upon the cotton farms. From Baton Rouge northward, how-
ever, the Memphis silt loam is well suited to the production of certain
classes of market-garden and truck crops, particularly of cabbage,
turnips, lettuce, radishes, asparagus, tomatoes, English peas, and
snap beans. It is not well suited to the production of the earliest
truck crops even in these locations, since they are forced to an earlier
maturity upon more sandy lands, and the crops grown upon the
Memphis silt loam are at a slight disadvantage when competing in
the early northern markets.

However, the yields secured upon the Memphis silt loam are fre-
quently superior to those obtained from the more sandy lands, a fact
which compensates to a considerable degree for the slightly later
date of maturity accompanied by somewhat lessened prices. It is
only within those portions of the type which are located near to
through lines of transportation that the production of the market-
garden or trucking crops is advisable, since their value is largely de-
termined by the possibility of rapid transportation to city markets.
Consequently only a small proportion of the total area of the Mem-
phis silt loam, and that located favorably with regard to shipment,
can be recommended for development for market gardening and
trucking purposes.

The soil itself through its inherent characteristics is particularly
well suited to the production of the later market-garden crops, and
of all such crops as may be used for the purposes of canning. It is
especially well adapted to the growing of tomatoes, peas, and beans,
both for shipment and for canning purposes. Such use of the Mem-
phis silt loam should be confined to the well-drained and little-eroded
portions of the type.

EXTENT OF OCCUPATION.

The more southern portions of the Memphis silt loam were occu-
pied to a limited degree for agricultural purposes by the civilized
tribes of Indians before white occupation had gained any extensive
foothold in the States where it is found. Since 1825 practically all
of the more level areas of the Memphis silt loam, wherever it occurs,
have been gradually cleared and occupied for crop production. The
chief limitation upon the agricultural development of this soil has
been that imposed by erosion. As a result, throughout a considerable
proportion of its extent, not over 25 to 35 per cent of the total area
of the type may be occupied, and in some localities, particularly near
the bluffs, not over 5 to 10 per cent is sufficiently level to permit of

12 SOILS OF THE. EASTERN UNITED STATES.

tillage. The fundamental cause for this lack of occupation still ex-
ists, and in some localities even to a more pronounced degree than in
the pioneer days. It is therefore scarcely possible that any greater
area of the Memphis silt loam may be successfully tilled than at
present. There is, however, an excellent opportunity for the more
intensive occupation of those portions of the type suited to tillage
purposes, and a beginning has already been made along these lines
in many areas where fruit growing, market gardening, and the pro-
duction of canning crops are made possible by adequate transporta-
tion facilities. Along the main lines of railroad extending from
Louisiana northward to the cities of the central States there are
many locations upon the Memphis silt loam which may become as
well known as Crystal Springs and Durant, Miss., for the produc-
tion of market-garden and truck crops. The first of these localities
is known as the greatest tomato-shipping point in the United States,
and it has maintained this preeminence for 25 years. At the second
point market gardening is of more recent development, but consider-
able areas are very profitably planted to the market-garden crops,
and the usefulness of the Memphis silt loam and its associated type,
the Richland silt loam, has been thoroughly demonstrated.

CROP ADAPTATIONS.

Taking into consideration the entire extent of its development, corn
constitutes the principal crop grown upon the Memphis silt loam.
Owing principally to differences in climatic surroundings, but also in
some degree to differences in cultural methods, the corn yields are
uniformly larger in the more northern regions occupied by the Mem-
phis silt loam, particularly in Illinois and Kentucky. The yields
range from 20 to 35 bushels per acre in these localities, giving an
average yield of about 25 bushels per acre through a long period of
years. In western Tennessee and in Mississippi corn is subordinate
in acreage to cotton, which constitutes practically the only other crop
grown upon the type. The yields are uniform!}' low, ranging from
10 to 20 bushels per acre and averaging about 18 bushels per acre in
Tennessee and not over 15 bushels per acre in Mississippi. Con-
sidering the inherent properties of the soil, these yields may only be
ascribed to one of two fundamental causes or to both operating to-
gether. The first of these would be climatic conditions unsuitable
to the 'product ion of the corn crop; the second, cultural methods
which were incompetent to bring out the best properties of the soil
for the production of this crop. In these more southern regions the
existence of certain well-tilled corn fields within the area of the
Memphis silt loam demonstrates beyond question that the avern^i1
yields secured by the majority of farmers by no means measure the
capabilities of this soil for the production of corn. Where complete

THE MEMPHIS SILT LOAM. 13

commercial fertilizers are used with the corn crop, supplemented by
the application of 300 or 400 pounds of cottonseed meal per acre,
yields of 30 and 35 bushels per acre of corn are readily obtained and
not infrequently exceeded. It may, therefore, be said that the Mem-
phis silt loam even under the conditions of the long, hot summers of
the more southern latitudes, is a fairly good corn soil when properly
treated.

In Illinois the Memphis silt loam is extensively devoted to the
production of winter wheat, the acreage of which ranks next to that
of corn. The yields are low, amounting to not over 10 bushels per
acre on the average, although proper tillage methods and a moderate
amount of fertilization result in the production of 15 bushels an
acre or more.

A small amount of winter wheat is also grown in western Ken-
tucky, but the yields are very low and the acreage is decreasing.

Cotton is grown to a considerable extent upon the Memphis silt
loam in western Tennessee, and constitutes the dominant crop in all
Mississippi areas where the type has been encountered. In Ten-
nessee the average yield for a considerable period of time is about
one-third bale per acre, although the better farmers secure one-half
bale or more through better tillage methods and the application of
larger quantities of commercial fertilizer.

In the State of Mississippi the Memphis silt loam, so far as it is
cultivated to cotton, constitutes an excellent upland soil for the pro-
duction of this crop. It must be held in mind that because of topo-
graphic difficulties and because of erosion not over 20 per cent of the
Memphis silt loam in the " Cane Hills " region is cultivated to any
crop, while not more than 35 to 40 per cent of the type is occupied
by crops in the " Flat Hills " region. The more level areas possess-
ing the deeper soil and being in the best condition for crop produc-
tion are devoted to cotton in both of these sections.

The average yield through a considerable period of years upon the
Memphis silt loam in Mississippi is between two-fifths bale and
one-half bale per acre. Again the better farmers upon well-cared-
for lands produce average yields of approximately three-fourths
bale per acre, and this yield might readily be attained over prac-
tically the entire tillable area of the type through the use of better
methods of tillage and the employment of additional amounts of
commercial fertilizer used in conjunction with applications of* cot-
tonseed meal at the rate of 300 to 400 pounds per acre.

The showing made by the Memphis silt loam as a general crop soil
is not particularly favorable, with the single exception of cotton in
the Mississippi counties where it is developed. In the majority of
instances the yields of corn reported are scarcely sufficient to pay
the interest upon the investment and the annual charges for working

14 SOILS OF THE EASTERN UNITED STATES.

the crop. In the case of winter wheat it is difficult to see where any
profit can be made from the production of the crop. In the case of
cotton, however, fair profits may be secured on the showing made by
this type. The failure of the Memphis silt loam to produce adequate
crop returns may not be attributed to the inherent characteristics of
the soil itself, since in all areas where it has been encountered, under
varying climatic conditions, the best farmers of those regions have
easily doubled the average crop yields reported for the counties.

One of the principal necessities for increasing the yields of corn,
wheat, or cotton upon the Memphis silt loam is the adoption of
some well-regulated crop rotation, planned with the definite pur-
pose of incorporating organic matter in the surface soil. In the
more northern States a rotation consisting of corn the first year, fol-
lowed by oats or winter wheat the second year, followed by two
years devoted to the growing of the mixed grasses, including clover,
will materially increase the crop-producing power of this type if the
rotation be adhered to for a few years. In the more southern areas
a crop rotation should be adopted which will provide for the sowing
of a winter cover crop between the rows in the corn field at the last
working of the corn, or of a winter cover crop to succeed the cotton.
In the majority of localities where the Memphis silt loam is found
south of the Ohio River, crimson clover and winter vetch are both
available for this purpose and may be grown without interfering
seriously with the cultivation or the picking of the cotton crop.
Either crop provides a considerable amount of green manure to be
turned under the succeeding spring in preparation for a succeeding
crop. It is also a fact that a rotation providing for the growing of
cotton followed by corn, followed by winter oats, these to be followed
by a crop of cowpeas will materially aid in maintaining the Mem-
phis silt loam against erosion and in restoring much needed organic
matter to the surface soil.

To secure the best results in crop production upon this type of
soil, fall or winter plowing — 6 to 9 inches deep — is requisite.
The lands should be " broadcasted " instead of having the ridges
plowed out into the middles. In the spring the land should be
thoroughly pulverized with a disk harrow and manures and fer-
tilizers applied prior to the planting of the crop. Except in the more
sloping areas, where it is necessary to adopt the contour method of
tillage, ridge cultivation is scarcely necessary upon the type. Instead,
the cultivation of the crops should be accomplished through the shal-
low stirring of the surface soil by the use of the spiked-tooth culti-
vator, and the small turn plow or sweep should be used, particularly
during the latter part of the season, only to plow out areas which are
badly in weeds or grass.

THE MEMPHIS SILT LOAM. 15

For the increase of the yields of the general farm crops upon the
Memphis silt loam, thorough preparation and tillage of the land, the
incorporation of organic matter, the rotation of crops, and the use
of cottonseed meal or other organic sources of nitrogen are all essen-
tial, particularly in the more southern areas of its occurrence. When,
in addition, the usual excellent natural drainage of this type is sup-
plemented by the installation of tile drains to remedy conditions of
deficient drainage over small level areas, the Memphis silt loam may
be depended upon to bring crop returns commensurate with the care
taken in its tillage.

In addition to the tilled crops already enumerated, the lespedeza,
or Japan clover, and Bermuda grass make excellent growth upon
this type of soil, the former growing particularly well in the shaded
areas of the thinly forested slopes, while the Bermuda forms its
characteristic mat of thick vegetation over open fields. Both of these
grasses are extremely valuable for grazing purposes and each makes
a fair cut of hay when its use for this purpose is desirable. The
Bermuda yields rather the larger tonnage of hay, but the lespedeza
hay is of excellent quality and of high feeding value. The use of
these grasses, together with cowpea hay, should enable the farmers
from the Ohio River southward who are tilling the Memphis silt
loam to keep such a number of live stock, either for meat or milk
production, as may seem desirable under the local conditions.

Market garden and truck crops. — In some of the more southern
areas where the Memphis silt loam has been encountered it has been
developed successfully as a market.-gardening and trucking soil. In
the Crystal Springs area, Mississippi, it constitutes an important soil
for the production of tomatoes and has contributed largely toward
the establishment of the reputation of that region for the production
of this crop. In addition to the tomatoes, English peas, Irish pota-
toes, cabbages, turnips, strawberries, and asparagus are all success-
fully produced upon the Memphis silt loam. A similar development
has taken place at Durant, Miss., upon the closely related type known
as the Richland silt loam. In both cases these similar soils have been
shown to be well adapted to the production of these market-garden,
trucking, and fruit crops. In addition, both Irish and sweet pota-
toes are raised to advantage on the Memphis silt loam from Louisi-
ana northward to Illinois. Irish potatoes yield from 75 to 150 bushels
per acre and are grown as an early trucking crop in the southern
areas and as a summer trucking crop or staple crop in the more
northern localities. Sweet potatoes are grown in Mississippi, Ten-
nessee, and Kentucky upon the Memphis silt loam, yielding from 75
to 250 bushels per acre of potatoes of fair quality. The sweet pota-
toes are marketed both as a truck crop and a staple crop, those reach-
ing maturity at the earlier dates constituting the truck crop.

16 SOILS OF THE EASTERN UNITED STATES.

Fruit crops. — In addition to strawberries, which are grown in
connection with the market-garden and truck crops in Mississippi,
the Memphis silt loam is also well suited to apple orcharding in the
more northern areas where it occurs. When care is used in the
selection of the orchard site to secure good air and water drainage,
the standard varieties for the region may be grown with profit.
From Kentucky southward the Memphis silt loam is also a good
peach soil, although but few commercial orchards have been de-
veloped upon it. These and numerous small plantings, principally
for home use, have demonstrated that the trees are thrifty and long
lived, and that the type might well be used throughout all its more
southern development for the production of peaches.

A considerable proportion of the Memphis silt loam remains in
forest growth. Wherever transportation is accessible a large part
of the mechantable timber has already been cut. The growth of
forest trees upon the type is rapid and with almost all of the species
suited to the soil and climate, commercial forestry would undoubtedly
be a desirable form for the utilization of the more eroded and hilly
portions of the type. The post oak, Spanish oak, scarlet oak, hickory,
black ash, and tulip are the native trees which dominate the forests
upon the type. Beech also grows in the ravines and hollows in the
cooler and more moist locations. Since these steeper portions of the
Memphis silt loam should remain in forest, in order to protect such
areas and adjoining tilled fields from excessive erosion, it would
seem desirable that the farm woodlot or the small individual forest
plantation should become a feature upon the majority of farms occu-
pied by the Memphis silt loam. In a great number of instances such
occupation would only require the careful selective cutting of timber
now growing, together with the protection of the areas from excessive
grazing and from fires. In case of necessity this practice might be
supplemented by the planting of such varieties of forest trees as
are needed to supplement the present stand.

The native grasses growing through the forested areas and upon
certain abandoned fields to be found within the area of the Memphis
silt loam are used to a limited extent for the pasturing of dairy cows,
beef cattle, and hogs. The extension of such forms of animal indus-
try upon the Memphis silt loam may be easily brought about when
it is economically desirable in any particular locality.

FARM EQUIPMENT.

In the majority of cases the equipment of teams and tools upon
the Memphis silt loam is scarcely adequate to the thorough and
profitable cultivation of the type. In too many instances the 850-
pound mule and the light-weight, one-mule plow, together with a
few minor tools, constitute practically the entire working equipment.

THE MEMPHIS SILT LOAM. 17

Since the soil needs deeper and more thorough cultivation, heavier
work stock and better tools should be employed in its tillage. The
Memphis silt loam is stone free, soft and friable, and easily worked,
unless it is handled when there is too much moisture present in the
surface soil. Except for the fact that many of the fields are of small
area and are circumscribed by deep gullies and eroded valleys, the
use of power machinery would be advisable over its entire extent.
Aside from this topographic limitation, the heavier machinery may
well be used. It would be particularly desirable to use the disk
plow and the disk harrow in the management of this soil, in order
that it might be thoroughly stirred to a considerable depth, and in
order that the trash, wTeeds, and other organic matter of the tilled
fields might be completely turned in and incorporated with the soil.
The equipment of farm buildings upon the Memphis silt loam
varies with the different areas in which it is found. The average
equipment is neither better nor worse than the buildings found upon
other types of the region.

SUMMARY.

The Memphis silt loam is an extensive soil type found principally
upon the east side of the Mississippi River from the confluence of
the Missouri southward to the vicinity of Lake Ponchartrain, but
found also in other localities in southern Illinois and in Arkansas
and Louisiana.

The surface soil is a brown or yellowish-brown silty loam of ex-
tremely variable depth, from 2 inches to more than 1 foot. The sub-
soil in almost all instances is a chocolate-brown or yellowish-brown
heavy silt loam.

The soil type is derived from the weathering of the loess, a silty
material associated with the glaciation of regions farther north.

The Memphis silt loam occurs at all altitudes from 50 feet above
sea level in Louisiana to 500 or 600 feet above sea level in Illinois and
Missouri. In general the drainage is good, although local areas
marked by a gray surface soil and the presence of iron concretions or
iron gravel are in need of tile underdrainage.

Owing to its soft, silty nature and its considerable elevation above
adjoining bottom lands, a large part of the Memphis silt loam has
been subjected to destructive erosion, and in such areas not over 20
per cent of the total extent of the type can be brought under tillage.
In other areas, more remote from active stream erosion, fully 35 per
cent of the type may be tilled, although erosion still constitutes a
serious problem in the handling of this soil.

In the more northern areas corn and winter wheat constitute the
dominant general farm crops produced upon the Memphis silt loam,
while apples constitute the principal fruit crop. In the more south-
ern areas cotton dominates all other crops, with corn second in acreage.

18 SOILS OF THE EASTEKN UNITED STATES.

The yields of the principal crops vary decidedly under different
attendant climatic conditions, and particularly with variations in the
effectiveness of the tillage and maintenance of the soil type.

The yields of the staple crops may best be increased through careful
attention to the prevention of erosion, the incorporation of organic
matter in the soil, the deeper and more thorough preparation of the
land, and the use of stable manures and cottonseed meal. Locally,
drainage is also required.

In certain localities, particularly in Mississippi, the Memphis silt
loam is a valuable soil for the production of market-garden and truck
crops. Of these, tomatoes, green peas, cabbages, turnips, asparagus,
strawberries, and Irish and sweet potatoes are the best suited for
production upon the type.

In these more southern locations also, the Memphis silt loam is
suited to the planting of commercial peach orchards, as has been
shown by small plantings of fruit for home use.

For the proper preparation and cultivation of the Memphis silt
loam heavier work animals and improved farm machinery are
requisite.

The inherent capabilities of the type are not fairly represented by
the crop yields at present secured, and improvements in yields should
follow the better cultural practices suggested in this circular.

Approved :

JAMES WILSON,

Secretary of Agriculture,

WASHINGTON, D. C., June 1%, 1911.

APPENDIX.

The following table shows the extent of the Memphis silt loam in the areas
surveyed to this time.

In the first column is stated the particular soil survey in which the soil was
encountered; in the second column, its extent of development in acres; and in
the third column, the volume of the Field Operations of the Bureau of Soils
in which the report upon the area may be found. Those desiring a detailed
description of the soil -and of the general conditions which surround it in any
particular area may consult these volumes in almost any public library.

Areas of Memphis silt loam, encountered in the Soil Survey.

Survey.

Area of soil.

Year of
publication,
Field
Operations.

Illinois:
Johnson County

Acres.
167, 104

1903

O' Fallen area, Missouri

192

1904

St. Clair County ' .«.

138,560

1902

Kentucky:
McCracken County ....

139, 776

1905

Louisiana:
East Baton Rouge Parish

16,640

1905

Mississippi;
Crystal Springs area

46 016

1905

Holmes County

2-20,288

1908

Jackson area ....

4'0 624

1904

Montgomery County

126, 848

1906

Smedes area

52,288

1902

Yazoo area

140,090

1901

Missouri:
O' Fallen area

5,184

1904

Tennessee;
Madison Count}* . . . ..

197,120

1906

'Mapped as Miami fine sandy loam.

O

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