GIFT OF

Aerie. Dent.

- ••; « ••

•4IVEHSITY

'"**•!

United States Department of Agriculture,

BUREAU OF SOILS— CIRCULAR No. 17.
MILTON WHITNEY, Chief of Bureau.

MANURIAL REQUIREMENTS OF THE PORTSMOUTH SANDY LOAM OF
THE DARLINGTON AREA, SOUTH CAROLINA.

The Portsmouth series of soils, of which the Portsmouth sandy loam
is the most extensive type, occurs mostly along the outer edge of the
Atlantic Coastal Plain, occupying level, slightly depressed areas in the
uplands. The soils are the result of sedimentary deposits modified by
swampy conditions, which have in recent times been lessened by the
establishment of better drainage.

The Darlington area of South Carolina, lying wholly within the Coastal
Plain, is situated northeast of the center of the State and includes all
of Darlington County and a part of Lee County. Its climate is mild,
with a well-distributed rainfall ranging from 40 to 50 inches annually.
For further information relating to the soils and agriculture of the area,
see Soil Survey of the Darlington Area, South Carolina, Field Operations
of the Bureau of Soils, 1902. pp. 291-307. In that report Portsmouth
sandy loam is described under the name of Goldsboro compact sandy
loam, a name which has since been discarded. It is the most exten-
sive and important soil type of the Darlington area, embracing an area
of about 118,000 acres. It is also the least understood soil of the area,
considerable of it being uncultivated and only indifferent yields being
secured from most of the fields under cultivation.

The soil used in the wire-basket tests, the results of which are reported
in subsequent pages, was collected from one of the best farms in the
Darlington area. Before selecting the location for sampling, a detailed
soil map of the whole farm was made and the fullest possible informa-
tion obtained in regard to its past history and the methods in use under
its present management. The owner and manager of this farm is looked
upon as one of the most up-to-date and successful farmers of Darlington
County, and inspection of his farm and the measure of success attained
will justify such a statement. It will be interesting, therefore, to note
the following brief sketch of the historical and natural features of this
farm, and the reader may also profit by the methods that have been
recently used to increase the productivity of the soil. .

HISTORICAL.

The farm, consisting of about 430 acres, is situated about 6 miles
east of Darlington, the county seat. The first fields were cleared from
the virgin forest growth at least seventy-five years ago, and, being natu-

rally fertile, at first gave abundant yields; but, as the forest mold
became exhausted and the yields steadily and rapidly decreased, new
fields were cleared as rapidly as possible and the least productive old
ones thrown out of cultivation. The chief crop interests, as at present,
were cotton and corn. With the abundance of land then available and
under the conditions of labor then existing this system of farming was
profitable and the planters enjoyed a high degree of prosperity. With
the change to a paid-labor system, the scarcity of new lands, and the
improved methods of cotton culture came the necessity of a radically
different system of farming. The methods in use in the past for the
culture of cotton and corn are too much a matter of history to require
description, but the methods in use at present will be fully described.
The beginning of marked improvement dates back about twenty-five
years, with the introduction of cowpeas as a soil enricher, and to this
medium, combined with crop rotation, deeper plowing, and more thor-
ough cultivation, most of the improvement is ascribed.

At the close of the early system the fields were for the most part so
run down as to produce not more than one-half bale of cotton per acre,
and many had long since ceased to be profitable ; others had suffered
from washing because no labor to care for them was to be had. As a
consequence it has been no easy matter to bring them to their present
improved condition.

The growing of bright tobacco is an industry of comparatively recent
introduction and the most approved methods are in use with this crop,
under the personal supervision of the planter.

SURFACE FEATURES AND DERIVATION OF THE SOILS.

The farm presents on the whole very level surface features. The cul-
tivated fields change but a few feet in elevation, and that but rarely.
However, a variation of 1 foot is often sufficient to produce a marked
change in soil. Open ditches are cut in the depressions wherever
necessary to secure adequate surface drainage, and tile underdrainage
will be necessary to secure the best results with many fields. The
slopes to the stream bottoms are quite abrupt, descending from 15 to 30
feet, with the crest of the descent often marked by a slight ridge or rise
occupied by one of the lighter colored, better drained soil types. The
stream bottoms are subject to overflow in seasons of high water and
are, therefore, largely uncleared.

The principal drainage is in a general southerly direction into Black
Creek. The inclination of many of the fields is so slight that the sur-
face water may be carried in almost any direction at will.

The soils, with the exception of those lying in the stream bottoms,
are derived from unconsolidated marine sediments of comparatively
recent age and present a variety of texture ranging from a heavy silt

loam to a loose coarse sand — changes from one extreme to the other
taking place rapidly and within narrow limits. The dip and depth from
the surface of the clayey stratum which underlies most of the area at no
great depth are of prime importance in its bearing on the crop interests
of the overlying soil, as this stratum forms the moisture reservoir, and
where more than 3 feet from the surface the lands are poorly suited
to the general crops of the section. On the other hand, where it ap-
proaches within a few inches of the surface on level lands, the soils
without special treatment are poorly suited to any but the grass and
small grain crops.

MANAGEMENT OP PLANTATION.

The agricultural methods in use on this plantation differ in many
respects from the general methods of the community and have been
found in practice to give uniformly better results. When the present
owner took charge of the place several years ago many of the fields were
in poor yielding condition, and the surface soil was very shallow. By
gradual and careful deepening of the preparatory plowing, a systematic
rotation of crops, and the continued use of cowpeas in the rotation the
soil proper has gradually deepened, until it now averages about 7 inches
in most of the tilled fields and is quite mellow and loamy in character.
In increasing the depth of the seed bed not more than one-half inch of
the subsoil was turned up at any one plowing, in order that the yield
should not be decreased in any one season by the addition to the sur-
face soil of an excessive proportion of unweathered materials. The aim
has been to follow as closely as possible the following rotation : Begin-
ning with corn for the first season, two rows of cowpeas are sown
between the corn rows at the time of last cultivation, from which the
vines are harvested for fodder, the roots alone remaining to improve
the soil. The second season the same field is planted in oats sown the
fall of the preceding season, followed by a crop of cowpeas after the
crop of oats is harvested, the vines in this case also being gathered for
fodder. The third season cotton is grown with, possibly, a single row
of some smaller variety of cowpea sown between the cotton rows in the
early fall, from which the vines are not gathered, but left to be plowed
under in the preparation for the fourth season. The fourth season the
field receives the same treatment as in the third, thus giving a four-year
rotation — corn, oats, cotton, and cotton, with at least two, and pos-
sibly four, crops of cowpeas. This is the system practiced on lands
not suited to the type of tobacco grown here, and when tobacco does
not enter the rotation. On the tobacco fields a different procedure is
necessary to preserve the required thinness of the leaf. Beginning with
tobacco the first season, cotton follows the second. The field is allowed
to lie idle the third, producing a crop of weeds which is plowed under
for the benefit of the succeeding 'crop of tobacco, making a three-season

rotation — tobacco, cotton, and fallow. It should be mentioned here that
no crop of cowpeas is sown in this rotation, not even in the cotton.

Cotton is planted from April 15 to April 30, about 1 inch deep in
rows 5 feet apart, which have been bedded by plowing several furrows
toward each other, and if the crop succeeds another cotton crop the new
beds are made in what were the furrows of the previous season. The fer-
tilizers used are mixed on the place from the simple ingredients and
usually consist of cotton-seed meal, acid phosphate or dissolved bone,
and sulphate of potash, so combined as to give a percentage of from 6
to 8 of phosphoric acid, 3 of ammonia, and 3 of potash. Of this mix-
ture, about 800 pounds per acre is used — 500 pounds at time of plant-
ing, under the seed, and 300 pounds as a surface application about
June 15. The manner of applying varies somewhat with the season,
and sometimes a top dressing of about 60 pounds per acre of nitrate of
soda is used. One row of dwarf cowpeas is planted between the cotton
rows at the last cultivation, or about the middle of July, and the vines
left on the ground.

Corn ground is prepared by plowing in beds 6 feet wide, then one
furrow is plowed back from each side and the planter run in that. Seed
is planted 2 inches deep in rows 6 feet apart, and thinned to 18 inches
apart in the row with one stalk in a place. The level of the corn rows is
at least 6 inches below the general level of the field. Fertilizer of the
same composition as that used on cotton is applied to the corn at the
rate of about 600 pounds per acre, but none is applied at the time of
planting. The corn is planted about April 1, and the first application
of 200 pounds of fertilizer is made beside the rows from May 20 to 30.
When the corn is about 2 feet high, another 200 pounds of fertilizer is
used, and the soil is plowed in toward the rows. The third application
of 200 pounds is made the latter part of June and more soil plowed in.
Early in July 100 pounds of nitrate of soda is applied, and a little later
two rows of cowpeas are planted between the corn rows. This method
is used by only a few planters in this section, but they are satisfied that
the resulting yield is nearly, if not quite, double that secured in the
usual way.

Oats generally follow corn, and are drilled in at the rate of 3 bushels
per acre, the latter part of October, the ground being plowed to a depth
of about 7 inches with a disk plow. No fertilizer is used, except a top
dressing of about 75 pounds per acre of nitrate of soda given in March,
and the crop is harvested in June, followed by a crop of cowpeas.

Bright tobacco entails a highly specialized treatment, and, as it is not
within the scope of this investigation, no detailed description will be
given. About 1,000 pounds of high-grade mixed fertilizer is used in
addition to 2 two-horse loads of stable manure per acre. The lighter
soils are used for this crop, and no attempt is made to increase the

yield of cotton which follows it on the same fields, as this might result
in detriment to the next tobacco crop. Thorough cultivation is given
all crops.

The conditions obtaining on this plantation are fairly illustrative of
the great advances made by the best farmers in this section of the
South in the last few years.

The residence is a spacious and comfortable two-story frame house,
approached by a magnificent avenue of Darlington oaks, and has an
extensive lawn of Bermuda grass well laid out and relieved by shrubs
and flower beds. The house is thoroughly plumbed, water being fur-
nished in ample quantity by a windmill.

The outbuildings and vegetable garden are in the rear of the house.
Good stable accommodations are furnished the stock, and the tools are
fairly well housed. The commissary shop, smokehouse, guano-house,
packhouse, gin, mill, and various store and curing houses for the
tobacco complete the buildings equipment. The cabins of the principal
servants and laborers are near by, while the rest of the field help are
located on rented tracts surrounding the area under consideration.
With the exception of the overseer, who exercises personal supervision
over the details of the field operations, the rest of the labor employed
is colored. The average wage is about 50 cents a day.

. The live stock consists on the average of 7 horses and 6 mules, which
are stabled, 15 head of cattle pastured during the day and stabled
nights, 25 head of swine penned at night, and about 30 hens. Only a
small part of the manure is saved and no special pains taken to prevent
waste of even this amount. The want of economy in this particular is
fully realized and steps will soon be taken to remedy it. The amount
of poultry kept is not an indication of the extent of that form of hus-
bandry in the locality, as it forms a large item with many farmers.

The adaptation of certain soils to particular crops has been well
recognized. The soils of the Norfolk series from their lighter and better
drained features have been used principally for bright tobacco in the
rotation mentioned in a preceding page, the adaptation of the better
drained Portsmouth types to oats and grain crops has been taken advan-
tage of. while the heavier and poorly drained soils have been utilized for
Bermuda grass, pasture, or left uncultivated until opportunity offered
for their improvement. Ridges of lighter, better drained soil and spots
of heavy, poorly drained phases occur in nearly every field, and their
textural and drainage differences are reflected sometimes to a marked
degree in the resulting growth. Where no textural differences are
apparent to account for the difference in productiveness, the presence
of a compact sand hardpan obstructing drainage or an inclination of
the clay substratum allowing too complete drainage is sufficient to
account for the observed differences.

Yields of cotton on this plantation do not vary much from 1 bale per
acre on the average for a good season, but this yield is never far
exceeded. Average yields of corn are from 60 to 70 bushels per acre,
and of oats about 60 bushels, although yields of from 80 to 100 bushels
are occasionally secured.

A greater diversification of crops and the introduction of some grasses
suited to this climate would be of much benefit. Bermuda grass is
grown to some extent and furnishes good pasturage while green, but
dies down and lies dormant during a portion of the year. It is an
excellent medium to arrest and prevent washing or gall spots.

The California or bur clover grows naturally to some extent, but is
of little value except as a soil improver, for it dies early in the summer
a'nd is little relished by stock. Many roots of this plant were examined
and were found uniformly to possess nodules, so it evidently has some
power of nitrogen fixation and may be of benefit to succeeding crops.

PARTICULAR DESCRIPTION OP THE SOIL TESTED.

As stated in the beginning of this circular, the Portsmouth sandy
loam is the most extensive soil type in the county, and it is also an
important type on this farnl. The soil of Portsmouth sandy loam, as
it occurs here, extends to an average depth of 7 inches and is a dark-
brown or gray sandy loam, mellow and friable when dry, but compact-
ing when wet on account of its rather high silt content. The sand par-
ticles are sharp and rather coarse. The subsoil is much more sandy,
but sticky and plastic and gray or pale yellow in color to a depth of 18
to 21 inches, where it grades rather abruptly into a mottled yellow and
drab sandy clay which is very sticky and impervious to water.

The greater part of this type lies in the eastern part of the farm. Its
surface features are very level — so much so that standing water remains
on the undrained fields after heavy rains, making a naturally cold, wet
soil. Underdrainage will be necessary with many fields before they can
be brought into the best condition. The sandy layer between soil and
deep subsoil is very apt to compact to such an extent as to become
almost a hardpan, and where present to any extent decreases the crop
yields.

Like the Norfolk types, this soil is derived from marine sediments,
but owes its present condition more to the result of long-continued swamp
conditions. The color of the soil is due to accumulation of organic
matter ; that of the subsoil immediately underlying it to a bleaching by
the organic acids liberated from above ; while the drab and mottled
colors of the substratum give evidence of the slight extent to which
atmospheric weathering has proceeded.

Throughout the county cotton will average from one-third to one-half
bale per acre, corn from 10 to 20 bushels, and oats about 25 bushels.

On this plantation much has been done toward the improvement of this
type with a large measure of success, and there is no reason why yields
of as much as 1 bale of cotton, 40 bushels of corn, and 50 bushels of
oats per acre should not be secured generally throughout the county by
proper treatment. The soil is perhaps better adapted naturally to the
production of oats than to any other crop commonly grown here.

RESULTS OF DIFFERENT MANUR1AL TREATMENTS OF PORTSMOUTH

SANDY LOAM.

The soil used in this test was a composite sample of about 500
pounds. It was taken to a depth of 7 inches, which is the present
depth of cultivation, and was considered thoroughly typical of this soil.
An acre from which this sample was secured was reserved for use in
field demonstration of such treatments as might give very beneficial
results.

The method consists in growing wheat for a period of twenty to tWenty-
five dajTs in small wire baskets, which, after being filled with soil and
planted with wheat, are sealed with paraffin, so that practically no
moisture is lost from the soil except through the transpiration of the
wheat. By periodically weighing the baskets and adding distilled
water from time to time a favorable moisture content of the soil is
maintained. At the close of the experiment the plants are cut and
weighed, so that both the green weight of plants and the water used in
[the course of growth are ascertained for each treatment. Under the
conditions of the test the draft made upon the soil by the plants, even
for so short a period, is greater than that which occurs in the field
during the full growing season.1

Iri the first test of this soil 20 manures and fertilizers, or combinations
thereof, were given in comparison with the untreated soil, there being 5
baskets for each 'treatment. The table on the following page gives the
treatments for those which produced a marked increase in growth,
together with the comparative weights of the plants, those from the
untreated soil being taken at 100.

1 For fuller description of the method see Circular No. 15, Bureau of Soils, U. S.
Dept. of Agr. •

8

Relative gro^vth of wheat plants on Portsmouth sandy loam ivith various

treatments.

Fertilizing materials and quantity applied per acre.

Relative
growth.

Untreated

100

Cowpeas 5 tons + lime 2 000 pounds

SB8

Sodium nitrate, 200 pounds, + potassium sulphate, 200 pounds, + acid phosphate, 200
pounds and lime 1,000 pounds

•J07

Sodium nitrate, 200 pounds, + potassium sulphate, 200 pounds, + acid phosphate, 200
pounds + lime. 2 000 pounds - --- -._.

205

Cowpeas, 5 tons ... -

204

Cowpeas 2j tons + lime, 1 000 pounds

199

Cowpeas 2i tons

Ifi7

Manure 10 tons + lime 2 000 pounds

156

Lime, 1,000 pounds - _.- . - ..-

147

Manure 10 tons

144

Lime 2 000 pounds

140

Sodium nitrate, 200 pounds, + potassium sulphate, 200 pounds, + acid phosphate, 200
pounds

130

Sodium nitrate, 200 pounds _. --

117

Acid phosphate, 200 pounds . . .

113

Potassium sulphate, 200 pounds - • .- ...

106

The above table shows that this soil, although thoroughly cultivated,
well supplied with commercial fertilizers, and subject to a systematic
rotation of crops, in which cowpeas are frequently grown, has responded
in a marked degree to many of the manurial treatments.

Cowpeas have produced decidedly the largest increase in growth,
applications of 2£ tons and 5 tons giving increases of 57 and 104 per
cent, respectively, and by supplementing this treatment with small
amounts of lime, the gain has been increased to 99 and 138 per cent.
The tops of young cowpeas were used in a green state, and the amounts
given in the above table are calculated to water-free substance. Two
and one-half tons of water-free tops per acre would be a good yield where
cowpeas are grown for the purpose of plowing under as a green manure,
although larger yields are sometimes secured. The roots of the cowpeas
will probably equal about one-half the weight of the tops, and not only
possess a manurial value, but have a marked beneficial effect upon the
soil as a result of- their extensive penetration. It is quite possible for
the benefits derived from the roots and stubble of a crop of cowpeas to
equal the benefits secured by plowing under the tops, and thus the tops
may be removed for forage or hay and still the soil be improved.

Lime has also produced very marked results on this soil, giving
increases of 47 and 40 per cent for applications of 1,000 and 2,000
pounds per acre, respectively. The same applications, when used in
addition to cowpeas, produced gains over and above that resulting from
the cowpeas amounting to 42 and 34 per cent, and when used in con-
nection with a complete commercial fertilizer consisting of 200 pounds
per acre each of sodium nitrate, potassium sulphate, and acid phos-

9

phate, the gain attributable to the lime is 77 and 75 per cent. It is
noteworthy in this connection that the smaller amount of lime, i. e.,
1,000 pounds per acre, has in each instance given slightly the larger
increase. This seems to show that while the lime is very beneficial,
the requirements of this soil are fully met by an application of 1,000
pounds per acre. Another striking thing in regard to the lime is that
it has produced nearly twice as much gain when used with a complete
fertilizer as when used alone, and, since commercial fertilizers are
extensively used, this makes the application of lime all the more
important. A complete commercial fertilizer as above used, costing a
little more than $10 per acre, gave only a moderate gain of 30 per cent,
and the addition of 1,000 pounds of lime, worth not more than $1.50,
increased the percentage gain to 107. The financial side of this is too
obvious to need discussion.

Barnyard manure has given a considerable increase, but from the
economical standpoint is not equal to cowpeas and lime, and, further-
more, its use is restricted for want of supply.

RESIDUAL EFFECT OF FERTILIZING MATERIALS.

In order to ascertain what the residual effects of the treatments might
be, a number of the baskets used in the experiments detailed in the
above table were replanted without further addition of fertilizing
materials. The following table gives the original treatments, and the
lines represent graphically the comparative growth for both the first and
second crops:

Com par at ire growth of wheat on Portsmouth sandy loam, for various treatments-
first and second crops.

Fertilizing materials and quantity applied per acre.

Comparative growth.

Sodium nitrate, 200 pounds, + potassium sulphate, 200

Cowpeas, 24 tons.

Cowpeas, 5 tons

Sodium nitrate, 200 pounds, + potassium sulphate, 200

Sodium nitrate, 200 pounds, + potassium sulphate, 200

Fresh soil, untreated

First crop ^ ^ ^_ Second crop ,

It should be noted in the above table that a fresh untreated sample
of soil was introduced in order to ascertain if the conditions during the
growth of the second crop compared favorably with those which pre-
vailed in case of the first. The untreated fresh soil gave a very slightly

10

greater growth than the original untreated sample gave for its first crop,
thus showing that the conditions for the second crop were equally as
favorable as for the first. The time of growth was identical.

The most striking feature about this test is the marked reduction in
the growth of the second crop, which is frequently less than half what
it was in the first instance. The relative growth as effected by the
treatments is essentially the same in both crops, but there has been a
marked reduction regardless of the treatment. In only two out of eight
instances has the residual effect been sufficient to exceed or equal the
original growth on the untreated soil.

It is a well-known fact in agriculture that continuous cropping with
the same crop tends to diminish the yields, and it would seem most I
probable in case of the above experiment that the first crop left something
in the soil that was harmful to the following one. The conditions in this
regard were probably intensified from the rapid growth and heavy draft
made on the soil in so short a time, and furthermore, the soil was |
replanted before time enough had elapsed for the oxidation or disap-
pearance of the noxious substances, a change which probably occurs to
greater or less extent in field practice, owing to the time which occurs 1
between crops.

The results herein given by the wire-basket method seem to be ?
thoroughly in accord with the observations that have been made in the
field and with the experience of the planters in Darlington County.
Arrangements have already been made for conducting field experiments j
on the plantation above referred to. for the purpose of determining if
certain of the most beneficial treatments will prove equally as effective
when tried under field conditions. The results are such as to justify
the suggestion that farmers, particularly those who have this type of
soil, should try in an experimental way the more promising applications
herein reported.

F. D. GARDNER,
In Charge of Soil Management.

F. E. BONSTEEL,

Approved: Assistant.

JAMES WILSON,

Secretary of Agriculture.

AUGUST 1, 1905.

O

RETURN
TO— ^

NRLE

1

2

3

4

5

6

ALL BOOKS MAY BE RECALLED AFTER 7 DAYS

DUE AS STAMPED BELOW

SENT ON ILL

JAN 1 0 1995

U. C. BERKELEY

1111 03^8

JUL & °

h> ^JVtU

JUL 1 9 1336

CIRCULATION DEF

i.

FORM NO. DD 19

UNIVERSITY OF CALIFORNIA, BERKEU
BERKELEY, CA 94720

VC 6789!

U.C.BERKELEY LIBRARIES