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CIKITLAR No. 8.— Revised edition, October, 1903. " (8.45.)

United States Department of Agriculture,

BUREAU OF SOILS.

U. S. DEPARTMENT OF AGRICULTURE,

Washington, I). C., August 3, 1901.
SIR:

About six months ago Dr. L. O. Howard, the P^ritornologist of this Depart-
ment, requested the cooperation of the Division of Soils in some practical
demonstrations of the feasibility of getting rid of the mosquito pest in certain
tidal swamps of the Atlantic Coast. Dr. Howard had been advising about the
extermination of mosquitoes in an area around Oyster Bay, L.I.,and requested
us to investigate the character of the soils of the tide marshes and the possibil-
ities of reclaiming them for agricultural purposes. Mr. Thos. H. Means, of the
Division of Soils, was assigned to this work, and made a preliminary examina-
tion, the results of which are briefly described in this circular.

It is believed that the information contained herein is sufficiently suggestive of
the possibilities of further work to warrant publication at this time, and that the
seriousness of this problem along the whole coast is certain to demand attention
in the future. The presence of the mosquitoes has been an important contribut-
ing cause to the abandonment of lands and the depreciation of property values
along the Atlantic, Gulf, and

MILTON WHITNEY,

Chief of Bureau.

Hon. JAMES WILSON,

Secretary of Agriculture^"

RECLAMATION OF SALT MARSH LANDS.

INTRODUCTION.

Tidal swamps and salt marshes are a prominent feature in nearly all
States which border the Atlantic or Pacific ocean. A few years ago
much was heard about their reclamation. Their value as farming lands
was clearly shown, and the fact that they were a serious menace to the
health of people in the vicinity was dwelt upon. About this time sev-
eral Government reports were issued. Notable among these reports
were "Sea Coast Marshes of the United States," by N. S. Shaler, pub-
lished in the Sixth Annual Report of the U. S. Geological Survey;
"Tidal Marshes of the United States," by D. M. Nesbit, published as
Special Report No. 7 of the U. S. Department of Agriculture, and
numerous notes and reports in the publications of the New Jersey Geo-
logical Survey. Some of these reports are out of print and all are now
• lillicult to obtain.

Within the last ten years investigations have been pursued by scien-
tists in Europe and this country which have conclusively proved that

certain species of mosquitoes are the most common, if not the only,
means of conveying malarial germs and of introducing those germs into
the human system. More recently mosquitoes have been found to be
the cause, and so far the only proved cause, of the infection of yellow
fever. Marshes and stagnant pools of water are the principal breeding
places of mosquitoes, and to remove the pests such places should be
drained and the lands reclaimed for agricultural purposes. In Italy the
mosquito pest has been the cause of the abandonment of vast areas of
land. , The salt marshes do not seem to offer the condition necessary
for the breeding of the few species of malaria mosquitoes existing in this
country, but they are breeding places for vast numbers of mosquitoes of
other species which annoy the residents and stock along much of the
coast line and in certain places impair the property valuation.

These recent discoveries of the cause of the infection from malaria
and yellow fever have resulted in a renewed interest in the means of
exterminating mosquitoes and incidentally in the drying out of marshes
and swamps. The writings of Dr. L. 0. Howard, Entomologist of this
Department, on mosquitoes have aroused the interest of the inhabitants
of mosquito and malaria infested localities in the subject of swamp
reclamation ; and this Bureau is in frequent receipt of letters inquiring
about the agricultural value of the marsh lands and methods for their
reclamation. A great many people seem willing to undertake the
drainage of these marshes and tidal meadows if it can be shown to them
that there will result a pecuniary profit. Therefore, to determine the
agricultural value of these soils a trip, was made to Oyster Bay, Long
Island, where reclamation work was in progress. Samples of the soil
and subsoil of the eel-grass mud were collected and subjected to lab-
oratory examination. No elaborate study of the subject is possible at
this time, so a simple statement of the conditions existing there is all
that can be made.

The conditions are sufficiently typical of coast marshes all along the
Atlantic coast to warrant the application to other localities of an}- les-
sons learned. The opinions of several earlier writers on the subject
have been quoted, and it is to be hoped the value of marsh lands has
been brought out clearly enough to direct more serious attention to
their reclamation. Shaler1 says:

The great advantage of the northern marsh areas is found in the fact that they
are generally near the larger centers of population of the country, when- they
will have a high value as market-garden soils or fields for the raising of hay.
When brought into their best state such areas will, measured by the price set
upon other lands in the same neighborhood, have a value of not less than $:>00
an acre. As the total reclaimable area bet ween New York and Portland (Maine i

1 Sea Coast Swamps of the Eastern United States, U, S. Geological Survey, 6th
Ann. Rep., p. 380.

probably exceeds 200,000 acres, the money value of their best state will amount
to at least $40,000,000. The cost of reclaiming these lands and reducing them
to cultivation should not exceed the fifth of this sum.

In European countries salt marshes are regarded as the most fertile
of lands. Large areas in Holland, Denmark, Germany, and Belgium
have been cultivated for many years. In England the Fens to the
extent of probably more than 1,000,000' acres have been diked and
ditched and are now in a "state of matchless fertility."

The reclamation of tidal lands to be successful at a minimum expense
should be managed by a man of experience in such matters. The ques-
tion of how to build dikes, the cheapest and most efficient method of
drainage to be emploj^ed, and the subsequent management of the soil
to bring it into a state of fertility at the earliest possible moment, are
all problems which require experience and judgment if the work is to
be a success. Unfortunately, in America there are no trained agricul-
tural engineers, nor is there an institution of learning which claims to
train expert agricultural engineers. The best person, then, to plan and
manage the reclamation is a civil engineer who has had experience in
some related work. Men of experience have a habit of charging well
for their services, but the money spent in fees to the right man is well
invested. Diking and ditching done by inexperienced or careless per-
sons will require more in repairs each year than would have been neces-
sary to insure proper supervision in the first instance.
Shaler (Loc. cit., p. 377) very aptly says:

Where efforts have been made to exclude the sea and actually till the land
,they have sometimes been unsuccessful,- owing to the failure of those who car-
ried on the trial to see the true condition of the work. It is very much to be
regretted that these experiments are not directed by some one trained in the
work as it is effected on the northern shores of Europe, who could have brought
to the task the accumulated experience of centuries ; if this had been done it is
tolerably certain that the process of turning these American marshes to agricul-
ture would now be well advanced.

RECLAMATION OF TIDAL MARSHES.

The first step in the reclamation of tidal marshes is the exclusion of
the sea. Ordinarily the marshes are covered by sea water only at high
tide — some of them at every high tide and others only at the highest or
spring tides. Salt water is harmful to most all plants and its
presence in the soil will effectively prevent the growth of ordinary farm
crops. To exclude the sea a dike or embankment must be built at least
2 feet higher than the highest tide. The method of building such dikes
must, of course, depend upon the locality, the exposure to wave action,
and the kind of dike-building material at hand. The material in most
common use is the sod and soil from the marsh itself. It is cut from the
swamp just inside of the position to be occupied by the dike and the exca-

vation acts as a drainage canal. The outer slopes of the dike should
have a grade of at least l£ horizontal to 1 vertical and should be shielded
from wave cutting by being well sodded Avith the marsh sod. On
exposed shores, where the wave action may be great, special precaution
should be taken to prevent washing by waves. The precaution may
take the form of masonry work or stone facing in the more substantial
dikes, or it may be a simple brush fence held in place by stakes driven
in the ground. Various expedients of this nature, both cheap and
effective, will suggest themselves to the engineer.

The ditch on the inside of the dike should be designed for drainage.
This ditch is usually situated along the lowest portion of the marsh and
is well placed to receive the lateral drains from the higher portions,
and, being at one end of the field, it is of little obstruction in the way
of cultivation. The dimensions of this ditch will be governed by the
amount of material required to construct the dike, if the dike material
is all taken from the ditch. A mistake is often made by digging the
ditch too wide. Consideration must also be given to the amount of water
emptying into the drains from the entire watershed and to be removed
in a given time. It is very seldom necessary to remove more than one-
half of an inch in depth of water in any twenty-four hours, and if the
ditches are planned to carry this much water the drainage is good.
Under certain conditions the open ditches should have a capacity of as
much as one inch in depth over the entire watershed tributary to the
ditch. The outlet of the main drains should be through the dike by
means of an automatic sluice or tidal gate. Ample room for storage of
the drainage water which may accumulate during high tide should be
allowed and the sluice gates should be of at least twice the capacity of
the main ditch, so that the entire drainage during high tide may be
removed during the interval of low tide.

On exposed coasts, where the maintenance of an outlet would be dif-
ficult or when the drainage is desired at a level lower than the lowest
tide, some other means of getting the water over the dike must be
planned. Windmills have been favored in European countries and have
been used in a small way in America. Various forms of pumps of
cheap construction and of great efficiency are now in the market, and
when driven by steam or gas engines are probably the cheapest form of
water-lifting machinery and are not dependent upon the vagaries of
the wind. Such a lifting plant need not be run all of the time, if stor-
age of the drainage water can be allowed. The conditions are excep-
tional where the pumping is necessary during the entire growing season.

UNDERDR AIN AGE .

Tile drains are the most effective means of removing water from land
and in the course of time will prove the cheapest. Farmers' Bulletin

No. 40 of this Department treats of farm drainage, and more detailed
information can be obtained from various publications on the subject.

In the ordinary condition in which tidal marshes are found it is unwise
to place tile until the land has had opportunity to drain and settle ;
otherwise in the settling the tile will be displaced and rendered of little
use. For this reason the ditches for the tile drains should be dug and
allowed to work as open drains until the excess of water from the soil
and the settling which accompanies the drainage is over. In cases of
very peaty swamps this sinking is great and continues for a long time.
More permanent open drains are then essential, but they should be
maintained as open drains no longer than necessary.

The distances between the drains will vary with the soil. In light
porous soils a distance of 300 feet is allowable, while in stiff and tight
clays drains 30 feet apart are sometimes necessary. The minimum
depth should be 3 feet for general farming or trucking, but for grass
land the drains are as effective if placed not deeper than from 18 inches
to 2 feet. In peat soils drains one-fourth to one-half mile apart are
often sufficient.

The grade on which the tile is to be laid is largely to be governed by
the height of the marsh above low water. The tendency is to use very
few of the li-inch or 2-inch tiles, but to make 3-inch tiles the smallest
used. The smaller tiles are found difficult, to lay and keep in operation
and the 3-inch tiles are not more expensive in the end and are much
more effective.

WASHING OUT THE SALT.

In salt marshes the tile drains are for two purposes : First to remove
the salt which has been left by the water, and second, to remove
promptly any excess of water which may be present or fall on the marsh.
In order that the salt may be removed it must be dissolved in water and
that water drained away. The usual way of reclaiming the meadows
is to allow the rain to wash out the salt. This is a slow practice, requir-
ing usually two or three years, but during this time some 'crop can
usually be grown. The sweetening can be accelerated by irrigation
with fresh water, if such is at hand. When the land is to be reclaimed
by irrigation small amounts of water should be applied at frequent
intervals rather than a single heavy flooding. If small applications of
water, not more than enough to cover the ground to a depth of from one
to 4 inches, with sufficient time between the applications to allow the
drains to carry away all the excess of water, be applied, the land can
l»c sweetened in one season or less. If the natural sweetening process
is followed, the native salt grass should be allowed to grow at first and
tame grasses will gradually take their place as the salt is removed by
the drainage.

When the cost of this method of frequent small floodings is found to

6

be prohibitive the land may be flooded to any depth and that depth
"maintained. Reclamation in this way is successfully carried on, but-
only water-loving crops can be grown during the sweetening process.

CULTIVATION OF MARSH.

After the land has been diked and ditched the best method of culti-
vation must be settled upon. If the soil is a tidal mud or silt, without
a covering of any kind, the cultivation can be commenced at once or
at least as soon as part of the salt is leached out. A great variety of
crops is adapted to such soils. Cleaning the land of all weed seed and
giving it an opportunity to be thoroughly aerated and weathered, by
planting for one or two years some cultivated crop, such as corn or sor-
ghum, is recommended. After that time, the best crop to select is one
suited to the locality ; whether it be truck, hay, cabbage, celery, or small
fruits will depend on the market and taste of the cultivator.

If, however, the tidal silt or mud, or eel-grass clay, as it is generally
known, is not at the surface, but is covered by a sod formed of the
partly decayed stems and roots of the salt grasses, a very different
method of treatment is necessary in order to get the soil in condition
to cultivate. If this sod is thin and well rotted, disking, deep plowing,
and thorough cultivation will generally break it up and enable a good
seed bed to be prepared ; but when it is a foot or more deep, and is in turn
underlain by half decomposed sod for a depth of a foot or two, the
breaking up and incorporation with the underlying soil in a short time
by cultivation are impossible. The best method of subduing such soil
is to burn off the sod. When it is fairly dry to a depth of 12 inches
fires should be started at a number of places and the sod allowed to
slowly smoulder. The burning should be carried on until the eel-grass
clay is close to the surface, or until the heavy roots are consumed.
Then by rolling and plowing the soil can be worked into condition.
Burning was formerly a practice in common use in European agricul-
ture, and is yet continued in the marsh soils of northern Germany,
Denmark, and Holland. The smoke of this burning is said at times-
to be noticeable as far as Italy. The sod is there burned to a depth of
10 or 12 inches only, and is then cultivated for from five to ten years
and burned again.

Such a practice will in time burn the entire peat of the swamps and
leave the underlying soil bare. The practice is \ery prodigal of organic
matter and is not to be recommended in America, especially since there
are crops which grow to best advantage in peat. In celery areas,
where such peaty soils are handled, burning is not the usual practice ;
in fact, the organic matter is the desirable part of the soil for the pro-
duction of celerj*. In such areas some cultivated crop is planted for
one or two years to give the peat an opportunity to decay. Rather

shallow open drains are dug and the soil slowly dried out. When the
first plowing is done the peat is often wet and boggy, so that it is impos-
sible to drive a horse across the bog. Ingenious farmers in California
attach a board to the feet of the horse the first time a bog is plowed.
Though most horses are not used to working with " tule shoes," as
they are called, they soon learn the proper swing to give the feet and
the work of plowing goes on nicely.

The judgment of the farmer must be the guide as to the best method
to be used to bring the land into good tilth. As a rule burning is a
waste of organic matter which in the later years of cultivation will be
needed. However, it is frequently better policy to burn off troublesome
sod and trust to later stable or green manuring to keep the supply of
organic matter up to the standard.

As a rule salt marshes are well supplied with lime in the form of
shells. Such soils in decaying will not need to be limed. Some-
times, however, the shells are not present and the soil is either acid in
its natural condition or soon becomes so through the decomposition of
the organic matter. Lime is then necessary to correct the acidity.
Either shell marl or shell lime is usually obtainable at low cost near
the coast.

Sulphide of iron is sometimes present in marsh lands and by its
decomposition gives off hydrogen sulphide gas and soluble iron
compounds or sulphuric acid, all of which are harmful to plants.
Thorough aeration will remove the hydrogen sulphide, but the poison-
ous iron compounds are more difficult to get rid of. Weathering and
aeration with the application of lime, both as carbonate and sulphate,
are the best methods known for the correction of the toxic effect of iron
in the soil. The iron is most often found only in spots and small areas
which slowly yield to cultivation. Very seldom does it cover large
areas.

CROPS DURING RECLAMATION.

As has been stated before, the easiest method of reclaiming the salt
marsh is to make the best use possible of the native salt grasses and to
allow the tame grasses to come in as the salt is removed by drainage.
This process can be accelerated by seeding with small quantities of
tame grass — timothy, red-top, and the rye grasses are all good — on the
parts of the marsh which contain the least salt. Three years will prob-
ably be the maximum time required to get a stand of tame grass.
If the time needed to complete this natural reclamation is too long the
process can be hastened by irrigation to assist in washing out the salt,
or salt-resisting crops may be planted. Asparagus, onions, sorghum,
and beets withstand large quantities of salt in the soil, and if the
soil is such as to be acceptable to any of these crops they will prove
profitable.

AGRICULTURAL VALUE OP SALT MARSHES.

To determine the agricultural value of such lands several samples of
the salt marsh areas around Oyster Bay, on Long Island, were collected
and subjected to laboratory examination. These are very probably
representative of much larger areas of salt marsh, and the results of
their examination will no doubt prove of interest to owners of salt
marshes all along the coast,

As has been indicated, there are many kinds of salt marshes and tidal
flats — some merely bare mud flats without vegetation, and others with a
heavy growth of grass and with a sod a foot or more thick. In any
locality such differences are due to the age of the marsh, and the two
cases mentioned can be considered as representing youth and old age in
marsh growth.

Mechanical analyses of tide marsh soils from Neic York.

Locality of soil.

Sand.

Silt.

Clay.

Per cent.

Ptr cent.

Per cent.

5.T79. Mud from tidal flat, west end Llovds Harbor, 0-6 inches

13.2

44.8

42.0

5375. Subsoil from outer marsh. Center Island, 36-66 inches ...

28.0

44.9

•_•: . i

5378. Subsoil from inner marsh. Center Island, 24-72 inches _..

38.0

37.1

24.9

Chemical analyses of tide marsh soils from New York.

Composition.

5379
Soil
0-6 in.

5374
Soil
0-36 in.

5375
Subsoil
36-66 in

5376
Soil
0-12 in.

__

.T3/<

Subsoil
12 -24 in.

5878
Subsoil
J4-72 in.

Lime (CaO)

Per cent.
0.43

Per cent.

Per cent.
0.31

Per cent.

Percent.

Percent.
0.41

Potash (KjO)

0.57

0.57

0 68

Phosphoric acid (PoOs)

0.16

0.14

0 12

Organic matter

7.18

29.00

5.36

34.70

25.49

10.90

Soluble in water .

2.M

4.07

2.55

1.87

3.87

3.56

The two tables show the results of the laboratory examinations of
the Oyster Bay samples. Sample No. 5379 was collected from the
tidal mud flat in the west end of Lloyds' Harbor, and represents the
soil on which the salt marsh grows, or, in other words, is the salt
marsh in youth. At low tide this mud flat is only a foot or 18
inches above the level of the water in the harbor, but at high tide it
is covered with salt water 4 or 5 feet deep. At the present time
the eel-grass has just commenced to grow on the mud, and it is found
in large, round hummocks dotting the mud flat. These hummocks
will gradually spread until the eel-grass is growing over the entire flat.
The growing grass greatly retards the flow of the water as the tide rises
and flows and the deposition of the sediment will be hastened. The
chemical analyses of this mud show it to be fairly rich in lime, abun-
dant in potash and with an adequate supply of phosphoric acid. The
7 per cent of organic matter will keep the clay soil in good tilth. The

9

amount of soluble matter (2.16 per cent), which an analysis showed
to be almost entirely from sea water, would prevent useful plant growth
other than salt grasses. The drainage of this flat would permit the
washing out of this salt.

Two marshes on Center Island which are being drained were examined.
These marshes — an inner marsh and an outer marsh — are separated by
a narrow neck. Across this neck a causeway had been built and sluice
gates placed in the culvert under the causeway. The gates were not
carefully watched and the tide water backed up on the inner marsh sev-
eral times. Notwithstanding this, the inner marsh was much fresher.
The outer marsh, however, was covered at high tide- twice a day and
contained a large amount of salt. Both of these marshes had a sod
about 1 foot thick and below this was decomposing sod to a depth of
3 feet and then came the eel-grass mud, very similar to that col-
lected in the west end of Lloyds Harbor.

Samples No. 5374 and No. 5375 were taken from the outer marsh
and represent the sod and decomposing grass roots and the underlying
eel-grass clay, respectively. The plant food analysis of the clay shows
it to be similar to the mud from Lloyds Harbor. The amount of soluble
salt in both soil and subsoil is seen to be high for plants other than salt
grasses. The sod is so light and tough that to decompose it thoroughly
for a seed bed would require several years ; therefore, it is likely that
burning will be found the best method. It is interesting to note that
the burning of these salt marsh soils causes part of the soluble matter
to disappear, so that afterwards the amount of soluble matter is smaller
than before burning.

Samples No. 5376, No. 5377, and 5378 were collected from the inner
marsh. The first two are the sod and decomposing sod, respectively,
and the last is the underlying eel-grass clay. The plant food analysis
shows this clay to be very similar to the Lloyds Harbor mud. The per-
centage of soluble salts in the surface foot of the inner marsh is lower
than that in any of the other samples. This shows that a start toward
sweetening has been made by the simple shutting out of the sea water.
The drainage of this inner marsh is in progress and three Samples of the
drainage water collected while the ditch was in process of construction
showed a salt content of 525, 860, and 860 parts salt per 100,000 parts
of water. If this drainage keeps up the marsh will in a short time be
much sweetened. The soil in this inner swamp is also very light and
should be burned if the intention is to cultivate it.

SUMMARY.

Salt marsh lands have long been considered the most fertile and val-
uable of lands. Practically no reclamation has been attempted in
America, and that which has been attempted has in many cases been

10

a failure or has been abandoned. There are well established methods
in use in the reclamation of salt marshes and if these are used the work
should be successful. There has never been a known case of failure to
effect complete reclamation, in which all proper precautions were taken.
After reclamation the lands are very fertile and should repay the expend-
iture for reclaiming them. It is generally conceded that 1 acre of
reclaimed salt marsh land is worth 4 or 5 acres of upland, and,
according to the well substantiated figures quoted from Shaler earlier
in this article, the cost of reclamation should not exceed one-fifth of
the final value of the land.

THOS. H. MEANS,
In Charge of Alkali Land Reclamation.

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