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                       SWEET CLOVER: UTILIZATION


                               H. S. COE

           Assistant Agronomist, Forage-Crop Investigations

                            [Illustration]


                         FARMERS' BULLETIN 820
                UNITED STATES DEPARTMENT OF AGRICULTURE


            Contribution from the Bureau of Plant Industry

                         WM. A. TAYLOR, Chief



               Washington, D. C.               May 1917

            WASHINGTON : GOVERNMENT PRINTING OFFICE : 1917


SWEET CLOVER may be utilized for feeding purposes, as pasturage, hay,
or ensilage. With the possible exception of alfalfa on fertile soil,
sweet clover, when properly handled, will furnish as much nutritious
pasturage from early spring until late fall as any other legume. It
seldom causes bloat.

Stock may refuse to eat sweet clover at first, but this distaste can be
overcome by keeping them on a field of young plants for a few days.

As cattle crave dry roughage when pasturing on sweet clover, they
should have access to it. Straw answers this purpose very well.

An acre of sweet clover ordinarily will support 20 to 30 sholes.

On account of the succulent growth, it is often difficult, in humid
climates, to cure the first crop of the second season into a good
quality of hay.

When seeded without a nurse crop, one cutting of hay may be obtained
the first year in the North and two or three cullings in the South.
Two cuttings are often obtained in the South after grain harvest. The
second year a cutting of hay and a seed crop usually are harvested.

Sweet clover should never be permitted to show flower buds before it
is cut for hay. It is very important that the first crop of the second
season be cut so high that a new growth will develop. When the plants
have made a growth of 36 to 40 inches it may be necessary to leave the
stubble 10 to 12 inches high.

In cutting the first crop of the second season it is a good plan to
have extension shoe soles made for the mower, so that a high stubble
may be left. In some sections of the country sweet clover as a silage
plant is gaining in favor rapidly.

This crop has given excellent results as a feed for cattle and sheep.
Experiments show that it compares favorably with alfalfa.

Sweet clover has proved to be a profitable soil-improving crop. The
large, deep roots add much humus to the soil and improve the aeration
and drainage. As a rule, the yield of crops following sweet clover is
increased materially.

Being a biennial, this crop lends itself readily to short rotations.

Sweet clover is a valuable honey plant, in that in all sections of the
country it secretes an abundance of nectar.

This bulletin discusses only, the utilization of sweet clover. A
discussion of the growing of the crop may be found in Farmers' Bulletin
797.




SWEET CLOVER: UTILIZATION.[1]

[1] The growing of this crop has been discussed in a previous
publication, Farmers' Bulletin 797, entitled "Sweet Clover; Growing the
Crop."




CONTENTS.


                                                   Page.

  General statement of the uses of sweet clover       3

  Sweet clover as a pasture crop                      4

  Sweet clover hay                                   10

  Sweet clover as a silage crop                      20

  Sweet clover as a soiling crop                     22

  Sweet clover as a feed                             23

  Sweet clover as a soil-improving crop              28

  Sweet clover in rotations                          31

  Sweet clover as a honey plant                      32




GENERAL STATEMENT OF THE USES OF SWEET CLOVER.


The utilization of sweet clover as a feed for all classes of live stock
has increased rapidly in many parts of the country, owing primarily to
the excellent results obtained by many farmers who have used this plant
for pasturage or hay, and also to the fact that feeding and digestion
experiments conducted by agricultural experiment stations show that it
is practically equal to alfalfa and red clover as a feed.

As a pasture plant, sweet clover is superior to red clover, and
possibly alfalfa, as it seldom causes bloat, will grow on poor soils,
and is drought resistant. The favorable results obtained from the
utilization of this crop for pasturage have done much to promote
its culture in many parts of the United States. On account of the
succulent, somewhat stemmy growth of the first crop the second year,
difficulty is often experienced in curing the hay in humid sections, as
it is necessary to cut it at a time when weather conditions are likely
to be unfavorable. When properly cured the hay is relished by stock.

At the present time sweet clover is used to only a limited extent for
silage, but its use for this purpose should increase rapidly, as the
results thus far obtained have been very satisfactory.

In addition to the value of sweet clover as a feed, it is one of the
best soil-improving crops adapted to short rotations which can be
grown. When cut for hay, the stubble and roots remain in the soil, and
when pastured, the uneaten parts of the plants, as well as the manure
made while animals are on pasture, are added to the soil and benefit
the succeeding crops. In addition to humus, sweet clover, in common
with all legumes, adds nitrogen to the soil. This crop is grown in many
sections of the country primarily to improve soils, and the benefits
derived from it when handled in this manner have justified its use, as
the yields of succeeding crops usually are increased materially.

The different species of sweet clover are excellent honey plants, as
they produce nectar over a long period in all sections of the United
States.

[Illustration: Fig. 1.--Cattle pasturing on sweet clover.]





SWEET CLOVER AS A PASTURE CROP.


With the possible exception of alfalfa on fertile soils, no other
leguminous crop will furnish as much nutritious pasturage from early
spring until late fall as sweet clover when it is properly handled.
Live stock which have never been fed sweet clover may refuse to eat
it at first, but this distaste is easily overcome by turning them on
the pasture in the spring, as soon as the plants start growth (fig.
1). Many cases are on record where stock have preferred sweet clover
to other forage plants. The fact that it may be pastured earlier in
the spring than many forage plants and that it thrives throughout
the hot summer months makes it a valuable addition to the pastures
on many farms. Sweet clover is an especially valuable forage plant
for poor soils where other crops make but little growth, and it is
upon such soils that thousands of acres of this crop are furnishing
annually abundant pasturage for all kinds of live stock. In many
portions of the Middle West, where the conditions are similar to those
of southeastern Kansas, it bids fair to solve the serious pasturage
problems. Native pastures which will no longer provide more than a
scant living for a mature steer on 4 or 5 acres, when properly seeded
to sweet clover will produce sufficient forage to carry at least one
animal to the acre throughout the season. In addition to this, a crop
of hay or a seed crop may be harvested from a portion of the land when
it is so fenced that the stock may be confined to certain parts of
the field at specific times. Land which is too rough or too depleted
for cultivation, or permanent pastures which have become thin and
weedy, may be improved greatly by drilling in, after disking, a few
pounds of sweet-clover seed per acre. Not only will the sweet clover
add considerably to the quality and quantity of the pasturage but
the growth of the grasses will be improved by the addition of large
quantities of humus and nitrogen to the soil.

Sweet clover has proved to be an excellent pasture crop on many of the
best farms in the North-Central States. In this part of the country it
may be seeded alone and pastured from the middle or latter part of June
until frost, or it may be sown with grain and pastured after harvest.

When sweet clover has been seeded two years in succession on separate
fields, the field sown the first year may be pastured until the middle
of June, when the stock should be turned on the spring seeding. When
handled in this manner excellent pasturage is provided throughout the
summer, and a hay or seed crop may be harvested from the field seeded
the previous season.

Some of the best pastures in Iowa consist of a mixture of Kentucky
bluegrass, timothy, and sweet clover. On a farm observed near Delmar,
Iowa, stock is pastured on meadows containing this mixture from the
first part of April to the middle of June. From this time until the
first part of September the stock is kept on one-half to two-thirds the
total pasture acreage. The remainder of the pasture land is permitted
to mature a seed crop. After the seed crop is harvested the stock
again is turned on this acreage, where they feed on the grasses and
first-year sweet-clover plants until cold weather. The seed which
shatters when the crop is cut is usually sufficient to reseed the
pastures. By handling his pasture land in this manner, the owner of the
farm has always had an abundance of pasture and at the same time has
obtained each year a crop of 2 to 4 bushels of recleaned seed to the
acre from one-third to one-half of his pasture land. This system has
been in operation on one field for 20 years and not until the last two
year's has bluegrass showed a tendency to crowd out the sweet clover.
It is essential that sufficient stock be kept on the pastures to keep
the plants eaten rather closely, so that at all times there will be an
abundance of fresh shoots.

Whenever the first crop of the second year is not needed for hay or
silage it can be used for no better purpose than pasturage. In fact,
it is better to pasture the fields until the middle of June, as this
affords one of the most economical and profitable ways of handling the
first crop. In addition to its value for pasture, grazing induces the
plants to send out many young shoots close to the ground, so that when
the plants are permitted to mature seed a much larger number of stalks
are formed than would be the case if the first crop were cut for hay.
The hay crop is likely to be cut so close to the ground that the plants
will be killed, whereas but little danger of killing the plants arises
from close pasturing early in the season. Excellent stands of sweet
clover will produce an abundance of pasturage for two to three mature
steers per acre from early spring to the middle of June.

Cattle which are pasturing on sweet clover alone crave dry feed. Straw
has been found to satisfy this desire and straw or hay should be
present in the meadow at all times, After stock are removed from the
field it is an excellent plan to go over it with a mower, setting the
cutter bar so as to leave the stubble 6 to 8 inches high. This will
even up the stand, so that the plants will ripen seed at approximately
the same date.

Experiments by many farmers in the Middle West show that sweet clover
is an excellent pasture for dairy cattle. When cows are turned on
sweet clover from grass pastures the flow of milk is increased and its
quality improved. Other conditions being normal, this increase in milk
production will continue throughout the summer, as the plants produce
an abundance of green forage during the hot, dry months when grass
pastures are unproductive. If pastures are handled properly they will
carry at least one milk cow to the acre during the summer months.

In many parts of the country sweet clover has proved to be an excellent
pasturage crop for hogs. When it is utilized for this purpose it
usually is seeded alone and pastured for two seasons. The hogs may be
turned on the field the first year as soon as the plants have made a
6-inch growth. From this time until late fall an abundance of forage
is produced, as pasturing induces the plants to send out many tender,
succulent branches. Pasturing the second season may begin as soon as
growth starts in the spring. If the field is not closely grazed the
second season it is advisable to clip it occasionally, leaving an
8-inch stubble, so as to produce a more succulent growth.

An acre of sweet-clover pasture ordinarily will support 20 to 30 shotes
in addition to furnishing a tight cutting of hay (fig. 2). For the best
growth of the hogs, they should be fed each day 2 pounds of grain per
hundredweight of the stock. Hogs are very fond of sweet clover roots
and should be ringed before being turned on the pasture. The tendency
to root may generally be overcome by adding some protein to the grain
ration. Meat meal serves this purpose very well.

The Iowa Agricultural Experiment Station conducted an interesting
pasturing experiment with spring pigs in 1910, In this experiment, pigs
weighing approximately 38 pounds each were pastured for a period of
141 days on two plats of red clover, a plat of Dwarf Essex rape, and a
plat of yellow biennial sweet clover. The pigs pasturing on each plat
received a ration of ear corn. The ration given to the pigs on one plat
of red clover and on that of rape was supplemented with meat meal to
the extent of one-tenth of the ear corn ration. The feed given to the
pigs pasturing on sweet clover was supplemented with meat meal at the
same rate during only the last 57 days of the test. The red clover was
seeded in 1908 and reseeded in 1909, so that the plat contained a very
good stand of plants at least one year old. The sweet clover was seeded
in the spring of 1910, while the rape was sown on April 4, 1910, in
24-inch rows. The pigs were turned on the forage plats on June 22.

[Illustration: Fig. 2.--Hogs pasturing on sweet clover.]

The results of this experiment, as presented in Table I, show that
sweet clover carried more pigs to the acre and produced cheaper gains
and a greater net profit per acre than either red clover or rape. To
judge from the date of seeding of the plants tested, it was to be
expected that the pigs pasturing on the sweet clover would not gain
as rapidly at first as those pasturing on the other forage plants,
as the growth of the sweet clover at this time was undoubtedly much
less than that of the other crops. This assumption is borne out by the
results given for the first 84 days of the test. During this period
the pigs on the rape made a net gain of $11.55 per acre and those on
the red clover $6.86 per acre more than those on the sweet clover. In
these computations corn was valued at 50 cents per bushel and hogs at
$6 per hundredweight. During the latter part of the experiment there
was but a scant growth of red clover on the plats, while the sweet
clover produced an abundance of forage, and during this period of the
experiment the pigs pasturing on sweet clover made a net gain of $10.14
per acre more than those pasturing on red clover and $17.41 per acre
more than those pasturing on rape. (Table I.) The difference in net
profits probably would have been greater had white sweet clover been
used instead of yellow sweet clover, as it makes a larger growth and
contains approximately the same ratio of food elements.

Table I.--Relative merits of Dwarf Essex rape, red clover, and yellow
sweet clover when pastured by spring pigs for 141 days, June 22 to
November 10, 1910.

  ---------------------------+------+-------+-------+--------+---------------+--------+-------
                             |      |       |       |        |Supplementary  |        |
                             |      |       |       |        |feed required  | Total  | Net
                             |      |       |       |        |   for 100     |  cost  |profit
                             |      |Initial| Total |Average |pounds of gain.| of 100 |  per
                             |Number| weight| gain, | daily  +-------+-------+ pounds |acre.[3]
  Forage tested, plat area,  |  of  |  per  |  all  |  gain  |Shelled| Meat  |   of   |
    and ration.              | hogs.|  hog. | hogs. |per hog.| corn. | Meal. |gain.[2]|
  ---------------------------+------+-------+-------+--------+-------+-------+--------+--------
                             |      |Pounds.|Pounds.| Pounds.|Pounds.|Pounds.|        |
  Rape (Dwarf Essex, 0.9     |      |       |       |        |       |       |        |
    acre), and ear corn[4]   |      |       |       |        |       |       |        |
    plus one-tenth meat meal.| 18   | 37.8  |2,801.7|  1.10  | 292.5 | 33.99 | $3.79  |  ......
      Reduced to acre basis. | 20   | ....  |3,113.0|  ....  | ..... | ..... |  ..... |  $88.64
                             |      |       |       |        |       |       |        |
  Clover (medium red, 0.8    |      |       |       |        |       |       |        |
    acre) and ear corn       |      |       |       |        |       |       |        |
    alone[4].                | 15   | 39.0  |1,790.0|   .84  | 370.6 | None. | 3.71   | ......
      Reduced to acre basis. | 18.75| ....  |2,237.5|  ....  | ..... | ..... | .....  |  51.20
                             |      |       |       |        |       |       |        |
  Clover (medium red, 0.8    |      |       |       |        |       |       |        |
    acre) and ear corn[4]    |      |       |       |        |       |       |        |
    plus one-tenth meat meal.| 15   | 39.0  |2,394.0|  1.13  | 299.3 | 34.77 | 3.84   | ......
      Reduced to acre basis. | 18.75| ....  |2,992.5|  ....  | ..... | ..... | .....  |  64.55
                             |      |       |       |        |       |       |        |
  Sweet clover[5] (yellow    |      |       |       |        |       |       |        |
    biennial, 0.8 acre) and  |      |       |       |        |       |       |        |
    ear corn[4] plus         |      |       |       |        |       |       |        |
    one-tenth meat meal.     | 18   | 37.8  |2,594.0|  1.02  | 313.6 | 24.70 | 3.70   | ......
      Reduced to acre basis. | 22.60| ....  |3,242.5|  ....  | ..... | ..... | .....  |  74.50
  ---------------------------+------+-------+-------+--------+-------+-------+--------+---------

[2] Corn valued at 50 cents per bushel, meat meal at $2.50 per
hundredweight.

[3] Hogs valued at $6 per hundredweight.

[4] During the first 84 days of the test, practically two-thirds of the
time, a limited ration of corn was given, while during the last 57 days
the pigs received a full feed.

[5] The pigs pasturing on sweet clover received meat meal only during
the last 57 days of the experiment.

An experiment reported by the New Jersey Agricultural Experiment
Station shows that a mixture of rape and sweet clover makes an
exceptionally fine pasture for hogs. In this experiment the mixture
of rape and sweet clover produced more pasturage than alfalfa and was
preferred to alfalfa by the hogs. It was seeded at the rate of 6 pounds
of Dwarf Essex rape and 10 pounds of sweet clover to the acre.

Sheep relish sweet clover and make rapid gains when pastured on it.
Care must be taken to see that pastures are not overstocked with sheep,
as they are likely to eat the plants so close to the ground as to kill
them. This is especially true the first year, before the plants have
formed crown buds. Yellow biennial sweet clover probably would not
suffer from this cause as much as the white species, because the plants
make a more prostrate growth and are not likely to be eaten so closely
to the ground.

Horses and mules do well on sweet-clover pastures. On account of the
high protein content sweet clover provides excellent pasturage for
young stock. No cases of slobbering have been noted with horses.


TAINTING MILK AND BUTTER.

Milk may be tainted occasionally when cows are pasturing on sweet
clover. However, the large majority of farmers who pasture sweet
clover on an extensive scale report very little or no trouble. The
flavor imparted to milk at times is not disliked by all people, as
some state that it is agreeable and does not harm the market value of
dairy products in the least. This trouble is experienced for the most
part in the early spring. The tainting of milk may be avoided by taking
the cows off the pasture two hours before milking and keeping them off
until after milking the following morning.


BLOATING.

Unlike the true clovers and alfalfa, sweet clover seldom causes bloat;
in fact, with the exception of the summer of 1915, only a few authentic
cases of bloat have thus far been recorded in sections where large
acreages are pastured with cattle and sheep. A number of cases of bloat
wore reported in Iowa during the abnormally wet season of 1915. No
satisfactory explanation for this comparative freedom from bloating
has been offered. It is held by some that the coumarin in the plants
prevents bloating, but this has not been established experimentally.


TREATMENT FOR BLOAT.

_Cattle._--If the case of bloat is not extreme, it may be sufficient to
drive the animals at a walk for a quarter or half an hour. In urgent
cases the gas must be allowed to escape without delay, and this is
best accomplished by the use of the trocar. In selecting the place for
using the trocar, the highest point of the distended flank equally
distant from the last rib and the point of the hip must be chosen.
Here an incision about three-fourths of an inch long should be made
with a knife through the skin, and then the sharp point of the trocar,
being directed downward, inward, and slightly forward, is thrust into
the paunch. The sheath of the trocar should be left in the paunch as
long as any gas continues to issue from it. In the absence of a trocar
an incision may be made with a small-bladed knife and a quill used to
permit the gas to escape. Care must be taken to see that the quill does
not work down out of sight into the incision.

Another remedy consists in tying a large bit, the diameter of a
pitchfork handle, in the mouth, so that a piece of rubber tubing may
be passed through the mouth to the first stomach to allow the gas to
escape.

When the animal is not distressed and the swelling of the flank is not
great, or when the most distressing condition has been removed by the
use of the trocar, it is best to administer internal medicine. Two
ounces of aromatic spirits of ammonia should be given every half hour
in a quart of cold water, or half an ounce of chlorid of lime may be
dissolved in a pint of tepid water and the dose repeated every half
hour until the bloating has subsided.[6]

[6] See "Diseases of Cattle," a special report of the Bureau of Animal
Industry.

For acute bloating the Kentucky Agricultural Experiment Station
recommends 1 quart of a 1-1/2 per cent solution of formalin, followed
by placing a wooden block in the animal's mouth and by gentle exercise
if the animal can be gotten up.

_Sheep._--Gas may be removed quickly from bloated sheep by using a
small trocar. The seat of the operation is on the most prominent
portion of the left flank.




SWEET-CLOVER HAY.


When sweet-clover hay is cut at the right time and cured properly it
is eaten readily by all classes of live stock. As the hay is rich in
protein, growing stock make gains on it comparable to the gains of
those fed on alfalfa. The quantity and quality of the milk produced
when the hay is fed to cows are approximately the same as when other
legumes are used. Hay which is cut the first year is fine stemmed and
leafy and resembles alfalfa in general appearance. Unless it is cut at
the proper time the second year, it will be stemmy and unpalatable.
Feeding experiments show that it contains practically as much
digestible protein as alfalfa and more than red clover, but the hay is
not as palatable as red clover or alfalfa when the plants are permitted
to become coarse and woody. When sweet clover is seeded in the spring
without a nurse crop in the northern and western sections of the United
States, a cutting of hay may be obtained the same autumn. When it is
seeded with a nurse crop in these regions, the rainfall during the
late summer and early fall will largely determine whether the plants
will make sufficient growth to be cut for hay. On fertile, well-limed
soils in the East, in the eastern North-Central States, in Iowa, and
in eastern Kansas a cutting of hay is commonly obtained after grain
harvest when the rainfall is normal or above normal. In many sections
of the country two, and at times three, cuttings of hay may be obtained
the second year (fig. 3).

In the South two, and sometimes three, cuttings may be obtained the
first year if the seeding is done without a nurse crop. When the seed
is sown in the spring with oats, two cuttings may be secured after oat
harvest. Three cuttings may be obtained the second year, although it is
the common practice to cut the first crop for hay and the second crop
for seed.




YIELDS OF SWEET-CLOVER HAY.


The total yields of sweet clover per acre for the season are usually
less than those of alfalfa except in the semiarid unirrigated portions
of the country. Sweet clover ordinarily yields more to the acre than
any of the true clovers.

[Illustration: Fig. 3.--Cutting sweet clover for hay in western Kansas.]

When the seed is sown in the spring in the North without a nurse crop,
yields of 1 to 3 tons of hay of good quality may be expected the
following autumn, The Massachusetts Agricultural Experiment Station
obtained 2,700 pounds of hay per acre in the fall from spring seeding,
while the United States Department of Agriculture obtained 3,000 pounds
of hay per acre in August from May seeding in Maryland. Yields of 1
to 2 tons, and occasionally 3 tons, have been obtained in Michigan,
Illinois, Iowa, Kansas, the Dakotas, and other States. In Illinois,
Iowa, and Kansas yields of 1 to 1-1/2 tons are often obtained after
grain harvest when weather conditions are favorable.

The first crop the second season yields 1-1/2 to 3 tons of hay to the
acre in the northern and western sections of the United States. The
second crop of the second season will yield from three-fourths to 1-1/2
tons to the acre, although this crop usually is cut for seed.

When sweet clover is seeded in the South without a nurse crop on fairly
fertile soil that is not acid, three cuttings of hay, averaging at
least a ton to the cutting, may be secured the year of seeding. When
the seed is sown in the early spring on winter grain, two cuttings,
yielding at least 1 ton to the cutting, may be obtained. The first crop
the second season yields on an average 1-1/2 to 3 tons of hay to the
acre. In 1903 the Alabama Canebrake Station obtained 2-1/2 tons of hay
after oat harvest and a total yield of 3 tons per acre from the same
field in 1904.


TIME TO CUT SWEET CLOVER FOR HAY.

The first season's growth of sweet clover does not usually get coarse
and woody and therefore may be cut when it shows its maximum growth in
the fall, In regions where more than one crop may be obtained the first
season, the first crop should be cut when the plants have made about a
30-inch growth.

The proper time to cut the first crop the second season will vary
considerably in different localities, depending very much upon the
rainfall, the temperature, and the fertility of the soil. In no event
should the plants be permitted to show flower buds or to become woody.
In the semiarid sections of the country sweet clover does not grow as
rapidly as in more humid regions. Neither do the plants grow as rapidly
on poor soils as upon fertile soils. In the drier sections the best
results usually are obtained by cutting the first crop when the plants
have made a growth of 24 to 30 inches. On fertile, well-limed soils in
many sections of the country a very rapid growth is made in the spring,
and often the plants will not show flower buds until they are about
5 feet high. On such soils it is very essential that the first crop
be cut when the plants have made no more growth than 30 to 32 inches
if hay is desired which is not stemmy and if a second growth is to be
expected.


HEIGHT OF STUBBLE TO BE LEFT WHEN CUTTING FOR HAY.

It is not necessary to leave more than an ordinary stubble when cutting
the sweet-clover hay crop in the fall of the year of seeding. A stubble
4 or 6 inches in height, however, will serve to hold drifting snow and
undoubtedly will be of some help in protecting the plants from winter
injury. While sweet clover without question is more hardy than red
clover, usually more or less winterkilling occurs, and any protection
which may be afforded during cold weather will be of considerable
benefit.

While the first crop in the second year comes from the crown buds, the
new branches which produce the second crop of the second year come from
the buds formed in the axils of the leaves on the lower portions of the
stalks which constitute the first crop, as shown in figure 4. These
branches usually commence growth when the plants are about 24 inches
high. In fields where the stand is heavy and where the lower portions
of the plants are densely shaded, these shoots are soon killed from
lack of necessary light. (Figs. 4 and 5.) The branches which are
first to appear and which are first to be killed are those closest to
the ground. It is therefore very important when cutting this crop to
cut the plants high enough from the ground to leave on the stubble a
sufficient number of buds and young branches to produce a second crop.

[Illustration: Fig. 4.--Sweet-clover plants, showing the direct
relation that exists between the thickness of stand, the time of
cutting, and the height at which the stubble must be cut if a second
crop is to be expected. The plant at the left was cut 10 day later than
the plant at the right. Note the height at which it was necessary to
cut this plant so that a second crop would develop and also the scars
on the stubble where young shoots had started earlier and were killed
from lack of sunlight. When the stand is thin the young shoots will
survive, as they did on the plant at the right, even though the field
is cut at a later date.]

Examination of hundreds of acres of sweet clover in different sections
of the United States during the summers of 1915 and 1916 showed that
the stand on at least 50 per cent of the fields was partly or entirely
killed by cutting the first crop the second season too close to the
ground. A direct relation exists between the thickness of the stand,
the height of the plants, and the height at which the stubble should
be cut if a second crop is to be harvested. It is very essential to
examine the fields carefully before mowing, so as to determine the
height at which the plants should be cut in order to leave at least one
healthy bud or young branch on each stub. In fact, the stand should
be cut several inches above the young shoots or buds, the stubble may
die back from 1 to 3 inches if the plants are cut during damp or rainy
weather.

[Illustration: Fig. 5.--Stubble of sweet clover collected in fields
where 90 per cent of the plants had been killed by cutting too closely
to the ground. The heavy stands in these fields were not cut until the
plants had made a growth of 36 to 40 inches. Note the scars on the
stubble where young shoots started, but died from lack of light.]

When fields of sweet clover contain only a medium-heavy stand and when
the plants have made no more than a 30-inch growth, a 5 to 6 inch
stubble usually will be sufficient to insure a second crop, but where
fields contain heavy stands--15 to 25 plants to the square foot--it
may be necessary to leave an 8-inch stubble. In many fields examined
in northern Illinois in June, 1916, heavy stands had been permitted to
make a growth of 36 to 40 inches before cutting. In a number of these
fields a very large percentage of the plants were killed when an 8
to 12 inch stubble was left. (See fig. 5.) A careful examination of
such fields showed that the young branches had started on the lower
portions of the stalks and had died from lack of light before cutting.
In semiarid regions, where the plants do not make as rapid growth as in
humid sections, they may, as a rule, be clipped somewhat closer to the
ground without injury.

On account of the difference in the growth that sweet clover makes
on different types of soil and on account of the difference in the
thickness of the stand obtained in different fields, it is impossible
to give any definite rule as to the proper height to cut the first crop.

[Illustration: Fig. 6.--Shoe sole to be placed on the inner shoe of the
mower, so that a high stubble may be left when mowing sweet clover:
_A_, End view of the back part of the sole; _B_, side view of the sole,
showing general shape; _C_, shape of the front end of the pole when
it is to be used on mowers having shoes of the type used on Deering
machines; _D_, forward end of the sole represented in _B_. The toward
end of the sole shown in _B_ and _D_ should be made for machines having
shoes of the type used on McCormick mowers.]

MOWER CHANGES FOR CUTTING SWEET CLOVER.

It is good practice to replace the shoe soles of the mower with higher
adjustable soles, so that a stubble up to 12 inches in height may be
left when cutting sweet clover, Shoe soles such as are shown in figures
6 and 7 may be made on any farm provided with a blacksmith's forge,
or they can be made at any blacksmith shop at a cost which should not
exceed $2.50. Preferably they should be of strap iron, about one-fourth
of an inch thick and 2 inches wide; however, old pieces of iron or
steel which may be found on the farm will serve the purpose.

[Illustration: Fig. 7.--Shoe sole to be Used on the outer shoe of the
mower, so that a high stubble may be left when cutting sweet clover;
_A_, End view of the back part of the sole; _B_, side view of the sole,
showing general shape; _C_, forward end of the sole to be used on
certain Deering machines; _D_, end view of the front part of sole shown
in _B_.]

Then these soles are to be placed on machines that have shoes of the
type used on the Deering mower, the forward 8 inches of the sole for
the inner shoe should be tapered gradually to a blunt point and bent
in such a manner that it will hook into the slot in the shoe. (Fig. 6,
_C_.) When the soles are to be placed on mowers having shoes of the
type used on McCormick machines, the forward 8 inches of the sole for
the inner shoe should be tapered gradually to about 1 inch in width,
bent forward so that it will fit against that portion of the shoe where
it is to be bolted, and have a hole of the proper size bored for the
bolt three-fourths of an inch from the end. (Fig. 6, _B_ and _D_.) The
bottom of the sole should be rounded, so as to run smoothly on the
ground when the cutter bar is raised to cut at different heights. The
back portion of the sole should be upright and should have holes bored
in it, so that it may be set for the cutter bar to rest at different
heights from the ground. Preferably the lower hole of the upright
should be located so that when the bolt in the shoe is run through it
the cutter bar will be 6 inches from the ground. It should be long
enough to permit four or five holes, 1 inch apart, to be bored above
the lower one. (Fig. 6, _A_.)

With some makes of machines it is not advisable to raise the cutter bar
higher than 10 inches from the ground, but when this is true the cutter
bar may be tipped upward, so that a 12-inch stubble is left.

The forward end of the shoe sole to be used on the outer shoe should
be tapered gradually to 1 inch from the end. The forward inch should
be one-fourth of an inch in width and bent slightly upward and inward,
so that a hook will be formed to fit into the slot in the front end of
the shoe. (Fig. 7, _B_.) The rest of the sole should curved, so that
it will run smoothly on the ground when the cutter bar is set to cut
at different heights. The upright which is bolted to the sole should
preferably be made of three-eighths by 1 inch material and should
have six holes, 1 inch apart, bored in it, so that the outer end of
the cutter bar may be raised to the same height as the inner end. On
practically all standard makes of mowers the outer shoe sole hooks into
the shoe instead of bolting to it, as is the case with the inner sole
on some machines. A wheel is used in place of a shoe sole on the outer
end of the cutter bar on some machines. When this is the case, the
upright to which this wheel is attached should be lengthened. On other
machines the forward end of the sole hooks into a slot in the shoe in
the same manner as the inner sole. In this event the front end of the
sole should be bent slightly upward and outward. (Fig. 7, _C_.)

Before shoe soles are made for any mower a careful examination should
be made of the shoes to determine the exact size required and the
manner in which they should be attached to the forward ends of the
shoes.


CURING AND HANDLING SWEET-CLOVER HAY.

One of the greatest difficulties in curing sweet clover is the fact
that the plants usually are ready to be cut for hay at a time of
the year when weather conditions are likely to be unfavorable for
haymaking. Little trouble is experienced in curing this crop in the
drier sections of the country where the methods used for alfalfa are
employed. The curing of sweet clover is more difficult than the curing
of either red clover or alfalfa, as the leaves are very apt to shatter
before the stems are cured. Every possible means should be employed to
save the leaves, as these constitute the best part of the hay. (See
Table II.)

Table II.--Average analyses of the leaves of four samples of well-cured
white sweet-clover hay.

[Analyses made by the Bureau of Chemistry.]

--------+-------------------------------------------------------------
        |          Constituents (per cent).
        +----------+-------+---------+---------+-------+--------------
Samples.| Moisture.|  Ash. | Ether   | Protein.| Crude | Nitrogen-free
        |          |       | extract.|         | fiber.|   extract.
--------+----------+-------+---------+---------+-------+--------------
        |          |       |         |         |       |
Leaves. |  8.70    | 10.92 |  3.09   |  28.20  |  9.28 |   39.78
Stems.  |  8.70    |  8.08 |   .70   |  10.16  | 39.45 |   33.06
        |          |       |         |         |       |
--------+----------+-------+---------+---------+-------+--------------

The hay collected for the above analyses represented the first cutting
the second season. The plants had made a 30 to 36 inch growth at the
time of cutting. It will be seen that the protein content of the leaves
is almost three times as great as that of the stems.

In the drier sections of the country or when the first crop of the year
of seeding is cut for hay in the North-Central States the mower may be
started in the morning as soon as the dew is off. The hay should remain
in the swath until the following day, or until it is well wilted, when
it should be raked into small windrows. After remaining in the windrows
for a day it may be placed in small cocks to cure. Cocks made from hay
which has dried to this stage will not shed water well and therefore
should be covered if it is likely to rain. It is important that the
cocks be made small enough to be thrown on the rack entire, as many
leaves will be lost if it is necessary to tear them apart.

[Illustration: Fig. 8.--Sweat clover curing in the cock.]

When sweet clover is permitted to dry in the swath, a large percentage
of the leaves will be lost in windrowing and loading unless handled
with the utmost care. Hay in this condition should never be raked while
perfectly dry and brittle, but should be raked into the windrow in the
early morning or in the evening, when it is slightly damp from dew. It
may then be hauled to the barn or stack after remaining in the windrow
for a day.

One of the most successful methods for handling sweet-clover hay,
especially in regions where rains are likely to occur at haying time,
is to permit the plants to remain in the swath until they are well
wilted or just before the leaves begin to cure. The hay should then
be raked into windrows and cocked at once (fig. 8). The cocks should
be made as high and as narrow as possible, as this will permit better
ventilation. In curing, the cocks will shrink from one-third to
one-half of their original size. It may take from 10 days to 2 weeks to
cure sweet clover by this method, but when well cured all the leaves
will be intact and the hay will have an excellent color and aroma. When
sweet clover is cocked at this time the leaves will cure flat and in
such a manner that the cocks will readily shed water during heavy rains
(fig. 9).

[Illustration: Fig. 9.--A cock of sweet-clover hay which has cured in
excellent condition and retained all of its leaves.]

When sweet-clover hay is to be stacked it is highly desirable that some
sort of foundation be made for the stack, so as to prevent the loss
of the hay which otherwise would be on the ground. Several feet of
straw or grass are often used for this purpose, but still better is a
foundation of rails, posts, or boards placed in such a manner that air
may circulate under the stack.

A cover should be provided for the stacks, either in the form of
a roof, a canvas, or long green grass. If none of these means is
practicable a topping of perfectly green sweet clover will cure with
the leaves flat and will turn water nicely.

It is well known that hay made from either red clover or alfalfa will
often undergo spontaneous combustion if put into the barn with too
much external moisture upon it. No instances of spontaneous combustion
in sweet-clover hay have been noted, but this may be due to the fact
that comparatively little sweet-clover hay is stored in barns. The same
precautions, therefore, should be taken with sweet-clover hay as with
red clover or alfalfa.




SWEET CLOVER AS A SILAGE CROP.


In some sections of the country sweet clover is gaining in favor as a
silage crop, either alone or in mixtures with other plants. The silage
made from this plant will keep better than that made from most legumes,
as it does not become slimy, as is so often the case with red clover or
alfalfa silage. It produces a palatable feed, which should contain more
protein than well-matured corn silage.

[Illustration: Fig. 10.--Filling the silo with sweet clover.]

When sweet clover makes sufficient growth after grain harvest, or when
seeded alone, it is not necessary to cut it for silage until fall. At
this time it may be run into the silo alone or in mixture with corn.
Excellent results have been obtained by placing alternate loads of corn
and sweet clover in the silo. (Fig. 10.)

When the first crop the second season is not needed for pasturage,
ensiling may prove to be the most economical and profitable way of
handling it, as it is necessary to cut this crop for hay at a time of
the year when the weather conditions in humid regions are very likely
to be unfavorable for haymaking. The large percentage of leaves which
usually are lost from shattering when harvesting the hay will be saved
when the crop is run into the silo.

The first crop the second season will produce approximately two-thirds
as much silage to the acre as corn when it is cut at the time it should
be cut for hay. The second crop may then be harvested for seed. When
sweet clover is handled in this manner, approximately two-thirds of the
total corn acreage which would be cut for silage may be permitted to
mature, as the first crop of sweet clover will replace the corn silage,
while the seed crop ordinarily will bring as much per acre as the corn.
In addition to this, the roots and stubble will add large quantities of
vegetable matter to the soil.

Some farmers do not cut sweet clover for silage until it is in full
bloom. When this is done, 10 to 12 tons of silage will be obtained per
acre, but the plants will be killed by the mowing.

[Illustration: Fig. 11.--Cutting sweet clover with a grain binder for
silage.]

When the green plants are ensiled, the crop preferably should be cut
with a grain binder. (See illustration on title-page and fig. 11.) This
will solve the difficulty of cutting a high stubble and will at the
same time bind the plants so that they may be run through the silage
cutter without difficulty. Green plants, and especially the first
crop of the second season, contain too much moisture to be run into
the silo immediately after cutting. In some cases quantities of juice
have been pressed out of the bottom of the silo, and as a result the
silage settled considerably. Analyses of the juice from one silo showed
that it contained 0.23 per cent protein and 2 per cent carbohydrates.
This loss of juice may be overcome by permitting the bundles to remain
in the field just as they come from the binder until the plants are
wilted thoroughly. Straw or corn stover may be placed in the bottom of
the silo to absorb some of the juice. If the plants contain too much
moisture it may be a good plan to mix some corn stover with the sweet
clover as it is run into the silo.

Several silos in Illinois have been filled with sweet-clover straw.
When this is done it is necessary to add sufficient water to moisten
the dry stems. These stems become soft in a short time and ensile
in good condition. When the seed crop is thrashed with either a
grain separator or a clover huller the stems are broken and crushed
sufficiently to render it unnecessary to run them through a silage
cutter. Care must be taken when ensiling the straw to add sufficient
water, if molding is to be avoided. It will probably be necessary
to add water at the blower and also at the top of the silo. It is
essential to tramp the straw thoroughly, so as to exclude as much air
as possible. After the silo is filled it should be covered with a layer
of green plants and thoroughly soaked with water.

Table III gives analyses of several sample of sweet-clover silage as
compared to corn silage.



Table III.--_Composition of sweet-clover silage and well-matured corn
silage._

 ---------------+---------+---------------------------------------------
                |         |    Constituents (per cent).
                |         +------+------+--------+----------------+-----
   Kind of      |         |      |      |        | Carbohydrates. |
                | Number  |Water.| Ash. | Crude  +------+---------+
    silage.     |   of    |      |      |protein.|      |Nitrogen-| Fat.
                |analyses.|      |      |        |Fiber.|  free   |
                |         |      |      |        |      | extract.|
 ---------------+---------+------+------+--------+------+---------+-----
                |         |      |      |        |      |         |
 White sweet    |         |      |      |        |      |         |
   clover;      |         |      |      |        |      |         |
  First year's  |         |      |      |        |      |         |
    growth[7]   |     1   | 73.7 | 1.73 |  3.17  |    20.8        | 0.65
  First crop,   |         |      |      |        |      |         |
    second      |         |      |      |        |      |         |
    season[2]   |     1   | 73.7 | 2.57 |  2.05  | 8.06 |  12.32  | 1.27
  Straw[8]      |     3   | 73.7 | 1.19 |  2.70  |13.59 |   8.33  |  .50
 Corn, well     |         |      |      |        |      |         |
    matured[9]  |   121   | 73.7 | 1.70 |  2.10  | 6.30 |  15.40  |  .80
                |         |      |      |        |      |         |
 ---------------+---------+------+------+--------+------+---------+-----

[7] Analysed by the Illinois Agricultural Experiment Station.

[8] Analysed by the Bureau of Chemistry.

[9] Analyses compiled by Henry and Morrison.

As shown in Table III the analyses of the first and second years'
growth of sweet clover compare favorably in food elements with corn
silage. It is to be expected that the silage made from the sweet clover
straw would contain less protein and carbohydrates than that made from
the entire plants, as most of the leaves shatter from sweet clover
before the seed crop is cut. Considerable protein and carbohydrates
were lost from the silage made from the first crop the second season,
as the plants were run into the silo as soon as they were cut. Much
juice was pressed from the bottom of this silo. An analysis of this
juice is given on page 21.




SWEET CLOVER AS A SOILING CROP.


As a soiling crop sweet clover has been used to only a very limited
extent. The amperage yields of green matter vary from 6 to 15 tons per
acre, The season for soiling may commence when the plants are 12 to
15 inches high and continue until flower buds appear. An area of such
a size that the plants may be cut every four or five weeks should be
selected. The plants should not be cut closer to the ground than 4
inches during the first part of the season and 9 to 12 inches during
the latter part of the season. On account of the high protein content
and the large amount of forage produced on a relatively small area,
sweet clover may profitably be fed in this manner when more desirable
soiling crops are not to be had.




SWEET CLOVER AS A FEED.


PALATABILITY OF SWEET CLOVER.

The woody growth of sweet clover as it reaches maturity and the bitter
taste due to coumarin have been the principal causes for live stock
refusing to eat it at first. On this account many farmers have assumed
it to be worthless as a feed. It is a fact that stock seldom eat the
hard, woody stems of mature plants, but it is true also that stock
eat sparingly of the coarse, fibrous growth of such legumes as red or
mammoth clover when they have been permitted to mature and have lost
much of their palatability. All kinds of stock will eat green sweet
clover before it becomes woody, or hay which has been cut at the proper
time and well cured, after they have become accustomed to it. Many
cases are on record in which cattle have refused alfalfa or red clover
when sweet clover was accessible. Milch cows have been known to refuse
a ration of alfalfa hay when given to them for the first time. Western
range cattle which have never been fed corn very often refuse to eat
corn fodder, or even corn, for a short time, and instances have come
under observation in which they ate the dried husks and left the corn
uneaten. When these cattle were turned on green grass the following
spring they browsed on the dead grass of the preceding season's growth,
which, presumably more closely resembled the grass to which they were
accustomed. Such preliminary observations should never be taken as
final, even when they represent the results of careful investigators.
When cowpeas were first introduced into certain sections of this
country much trouble was experienced in getting stock to eat the vines,
either when cured into hay or made into ensilage. This difficulty,
however, was soon overcome.

It is very true that stock which have never been pastured on sweet
clover or fed on the hay must become accustomed to it before they will
eat it, but the fact that sweet clover is now being fed to stock in
nearly every State indicates that the distaste for it can be overcome
easily and successfully. As sweet clover usually starts growth earlier
in the spring than other forage plants and as the early growth
presumably contains less coumarin than older plants, stock seldom
refuse to eat it at this time. Properly cured hay is seldom refused by
stock, especially if it is sprinkled with salt water when the animals
are salt hungry.


COMPOSITION OF SWEET CLOVER.

Sweet clover, like most legumes, contains a relatively high percentage
of protein, thus making it a source of that valuable constituent of
feeds needed for growing stock and for the production of milk. Table
IV shows the relative composition and digestibility of sweet clover as
compared to some other feeds.



Table IV.--Composition and digestibility of sweet clover compared with
that of other forage crops.

AVERAGE PERCENTAGE COMPOSITION OF SWEET CLOVER AND OTHER FORAGE CROPS.

  -----------------+---------+--------------------------------------------
                   |         |          Constituents (per cent).
                   |         +------+-----+--------+----------------+-----
                   |         |      |     |        |Carbohydrates.  |
                   | Number  |      |     |        +------+---------+
  Kinds of forage. |   of    |Water.| Ash.| Crude  |      |Nitrogen-| Fat.
                   |analyses.|      |     |protein.|Fiber.|  free   |
                   |         |      |     |               | extract.|
  -----------------+---------+------+-----+--------+------+---------+-----
                   |         |      |     |        |      |         |
  Green crop:      |         |      |     |        |      |         |
   Sweet clover[10]|     18  | 75.6 | 2.1 |   4.4  |  7.0 |  10.2   | 0.7
   Alfalfa[10]     |    143  | 74.7 | 2.4 |   4.5  |  7.0 |  10.4   | 1.0
   Red Clover[10]  |     85  | 73.8 | 2.1 |   4.1  |  7.3 |  11.7   | 1.0
                   |         |      |     |        |      |         |
  Hay (moisture-   |         |      |     |        |      |         |
    free basis):   |         |      |     |        |      |         |
   White sweet     |         |      |     |        |      |         |
     clover[11]    |     37  | .... | 8.2 |  17.6  | 28.2 |  43.0   | 3.0
   Yellow sweet    |         |      |     |        |      |         |
     clover[11]    |      3  | .... | 6.4 |  15.8  | 35.6 |  39.0   | 2.6
   Alfalfa[11]     |    211  | .... | 9.6 |  17.4  | 29.8 |  40.3   | 2.9
   Red clover[11]  |     99  | .... | 7.0 |  15.6  | 27.7 |  44.9   | 3.9
   Timothy[11]     |    194  | .... | 6.2 |   8.2  | 32.5 |  49.9   | 3.2
  -----------------+---------+------+-----+--------+------+---------+-----

DIGESTIBLE NUTRIENTS OF SWEET CLOVER AND OTHER FORAGE CROPS WHEN FED TO
SHEEP.[12]

  ----------------+----------+---------------------------------+---------
                  |          | Digestible nutrients in 100     |
                  |          |   pounds of air-dried hay.      |Nutritive
                  |Dry matter+--------+--------+-------+-------+ratio.[13]
  Kinds of forage.|  in 100  |Protein.|Carbohy-| Fat.  | Dry   |
                  |  pounds. |        | drates.|       |matter.|
  ----------------+----------+--------+--------+-------+-------+---------
                  |          |        |        |       |       |
  White sweet-    |          |        |        |       |       |
    clover hay    |    92.2  | 11.88  |  36.68 | 0.49  | 56.12 | 1:3.2
  Pea hay         |    93.1  | 11.24  |  48.55 |  .71  | 62.5  | 1:4.5
  Alfalfa hay     |    92.2  | 11.73  |  42.38 |  .72  | 60.90 | 1:3.8
  (second cutting)|          |        |        |       |       |
  ----------------+----------+--------+--------+-------+-------+---------

[10] Analyses taken from Henry and Morrison's "Foods and Feeding."

[11] Analyses compiled by the Bureau of Chemistry.

[12] Experiments conducted by the Wyoming Agricultural Experiment
Station.

[13] The nutritive ratio is the ratio which exists between the
digestible crude protein and the combined digestible carbohydrates and
fat.

Table IV shows that the percentage composition of both green and cured
sweet clover compares favorably with that of alfalfa and red clover.

Perhaps the most interesting point shown in this table is that the
fiber content of white sweet clover, whether green or cured into hay,
is no greater than that of alfalfa. It is understood, however, that
the plants collected for these analyses were taken when they were
at the proper stage for curing into hay. Table IV also shows that
the digestible nutrients of sweet clover when fed to sheep compare
favorably with alfalfa. It was stated that the sweet-clover hay used
for this experiment was stemmy and that it had not been cut until it
had become woody. The pea hay had passed the best stage for cutting
when it was harvested, while the alfalfa hay was in excellent condition.

In a feeding experiment with sheep conducted by two students at
the Iowa State College it was found that the protein digested in
sweet-clover feed alone was 69 per cent and that the addition of
corn to the hay ration increased the digestibility of sweet clover
to 82 per cent. Alfalfa and red clover showed similar increases of
the digestibility of the protein content when corn was added to the
ration. The percentage of digestibility figured for the protein in
the corn was the average of a number of digestion experiments. The
probability is that the digestibility of the corn was also increased
by the presence of the hay in the ration, so that not all the increase
in the digestibility should be credited to the hay constituents of the
different rations.


FEEDING EXPERIMENTS WITH SWEET CLOVER.

Few agricultural experiment stations have carried on definite feeding
experiments to determine the value of sweet clover compared with other
feeds.

The South Dakota Agricultural Experiment Station reported an experiment
in which lambs were fed on sweet-clover hay in comparison with alfalfa,
pea-vine, and prairie hay. In this experiment the lambs made a better
gain at a less cost when fed sweet-clover hay than when fed pea-vine
hay, but not as large a gain as when fed alfalfa hay. The results of
this experiment are shown in Table V.

Table V.--Feeding experiment with lambs in South Dakota, showing the
comparative value of different kinds of hay as roughage.

[Grain ration consists of oats and corn in all cases; roughage varies.]

 --------------+-------+--------+----------------+---------------+-------
               |       |        | Average weight.|Required for 1 |
               |       |        |                |pound of gain. |Average
               |       |        +--------+-------+-------+-------+ daily
               | Number|Duration|        |       |       |       |  gain
  Roughage fed.|  of   |of test.|At be-  |At end.|Grain. |  Hay. |  per
               | lambs.|        |ginning.|       |       |       |  head.
 --------------+-------+--------+--------+-------+-------+-------+-------
               |       |        |        |       |       |       |
               |       | Days.  |Pounds. |Pounds.|Pounds.|Pounds.|Pounds.
 Prairie hay   |   16  |   67   |  83.6  | 107.9 |  5.09 |  2.35 |  0.36
 Pea-vine hay  |   10  |   67   |  83.6  | 107.3 |  5.40 |  3.15 |   .35
 Alfalfa hay   |    5  |   67   |  81.4  | 119.4 |  3.36 |  3.02 |   .56
 Sweet-clover  |   10  |   67   |  84.7  | 113.6 |  4.42 |  3.19 |   .43
   hay         |       |        |        |       |       |       |
 --------------+-------+--------+--------+-------+-------+-------+-------

The Wyoming Agricultural Experiment Station also performed an,
interesting experiment with lambs. A number of pens of 10 to 40
lambs each were fed different mixtures of feeds for 14 weeks. Those
receiving sweet-clover hay, corn, and a small amount of oil meal
made an average gain of 30.7 pounds per head, as compared with 20.3
pounds for those receiving native-grass hay, oats, and oil meal. Those
receiving alfalfa hay and corn made a gain of more than 34 pounds per
head. The results obtained with four pens of lambs in this experiment
are given in Table VI.



Table VI.--Results of feeding tests of lambs in Wyoming covering 14
weeks.

  -------------+------+-------+-----------------------------------------------
               |      |       |     Required for 100 pounds of gain.
               |      |       +-------+-------+-------+-------+-------+-------
               |      |Average|Sweet- |       |       |       |       |
               |Number| gain  |clover |Native |Alfalfa| Corn. | Oats. | Oil
   Ration.     |  of  | per   | hay.  | hay.  |  hay. |       |       | meal.
               |lambs.| head. |       |       |       |       |       |
  -------------+------+-------+-------+-------+-------+-------+-------+-------
  Sweet-clover |      |Pounds.|Pounds.|Pounds.|Pounds.|Pounds.|Pounds.|Pounds.
   hay, corn,  |      |       |       |       |       |       |       |
   and oil meal|      |       |       |       |       |       |       |
  (old process)|   10 |  30.7 | 637.5 | ..... | ..... | 293.2 | ..... |  20.5
               |      |       |       |       |       |       |       |
  Native-grass |      |       |       |       |       |       |       |
   hay, oats,  |      |       |       |       |       |       |       |
   and oil meal|      |       |       |       |       |       |       |
  (old process)|   40 |  20.3 | ..... | 606.7 | ..... | ..... | 460.5 |  25.0
               |      |       |       |       |       |       |       |
  Alfalfa hay  |      |       |       |       |       |       |       |
   and corn    |   10 |  34.4 | ..... | ..... | 557.5 | 261.6 | ..... | .....
               |      |       |       |       |       |       |       |
     Do        |   40 |  34.3 | ..... | ..... | 557.3 | 286.5 | ..... | .....
               |      |       |       |       |       |       |       |
  -------------+------+-------+-------+-------+-------+-------+-------+-------

The sweet-clover hay used in this experiment was described as stemmy
and more than a year old; yet it was eaten up clean by the lambs.

The South Dakota Agricultural Experiment Station conducted an
experiment in which steers were fed corn silage and various kinds of
hay, including sweet clover. The steers which were fed corn silage and
sweet-clover hay made an average daily gain of 2.45 pounds, at a cost
of $4.34 per hundred pounds of gain, whereas the steers which were
fed corn silage and red-clover hay made an average daily gain of 2.29
pounds, at a cost of $4.55 per hundred. The steers that were fed corn
silage and alfalfa hay made an average daily gain of 2.49 pounds, at
a cost of $4.30 per hundred. In computing the cost of the gains, corn
silage was valued at $3 per ton, alfalfa, red-clover, and sweet-clover
hay at $10 per ton, and prairie hay at $6 per ton. The results of
this experiment, as given in Table VII, show that sweet-clover hay is
practically equal to red-clover and alfalfa and greatly superior to
prairie hay for roughage for steers.

Table VII.--Feeding experiments with steers in South Dakota, showing
the value of sweet-clover hay as compared with some other kinds of hay.

[Corn silage fed in all cases; kind of hay varies.]

 ------------+-------+--------+----------------+-------+---------------+------
             |       |        |Average weight. |       |Feed per pound | Cost
             |       |        +--------+-------+       |   of gain.    | per
             |Number |        |  At    |       |Average+-------+-------+ 100
             |  of   |Duration| begin- | At    | daily |       |       |pounds
  Roughage.  |steers.|of test.|  ning. | end.  | gain. |Silage.| Hay.  |  of
             |       |        |        |       |       |       |       | gain.
 ------------+-------+--------+--------+-------+-------+-------+-------+------
             |       | Days.  | Pounds.|Pounds.|Pounds.|Pounds.|Pounds.|
  Red-clover |       |        |        |       |       |       |       |
    hay      |    4  |   91   |   775  |   983 |  2.29 |   25  |  1.5  | $4.55
             |       |        |        |       |       |       |       |
  Sweet-     |       |        |        |       |       |       |       |
   clover hay|    4  |   91   |   774  |   997 |  2.45 |   23  |  1.5  |  4.34
             |       |        |        |       |       |       |       |
  Alfalfa    |    4  |   91   |   775  | 1,005 |  2.49 |   23  |  1.6  |  4.30
             |       |        |        |       |       |       |       |
  Prairie    |    4  |   91   |   769  |   951 |  2.01 |   29  |  1.5  |  4.79
     hay     |       |        |        |       |       |       |       |
 ------------+-------+--------+--------+-------+-------+-------+-------+------

The results of these various experiments are being duplicated every
year by many feeders. Each year in the Middle West and Northwest many
cattle that bring high prices are being fed with no other roughage than
sweet-clover hay. Steers which have been pastured entirely on sweet
clover have brought in the Chicago market $1 per hundredweight more
than ordinary grass-pastured stock marketed from the same locality and
at the same time.

Excellent results were obtained in Lee County, Ill., from feeding
steers sweet-clover silage made from plants which had matured a
seed crop. For this experiment 91 head of steers 2 and 3 years old,
averaging 1,008 pounds per head, were purchased at the Kansas City
stock yards on November 16, 1915, at a cost of $6.30 per hundred.
These steers were shipped to a farm at Steward and immediately turned
on 120 acres of cornstalks. They were fed nothing in addition to the
cornstalks until January 14, 1916, when they were put into the feed
lot. While they were not weighed when turned into the feed lot, the
owner of the steers stated that in his estimation they had gained
but little, if any. During the 60 days these steers were in the feed
lot they were fed 25 bushels of snapped corn twice a day and as much
sweet-clover silage as they would eat. These animals had access to
sweet-clover straw during the first part of the feeding period, but
after this was consumed they had only oat straw as roughage. At the
end of the feeding period they were sold on the Chicago market at the
average price of $8.25 per hundred, netting approximately $30 per head.
The average weight of these steers in the Chicago yards was 1,177
pounds, 169 pounds more than when purchased in Kansas City.

A most remarkable feature of this experiment is the fact that the
steers were fed almost entirely material which would have been
considered of little value by the average farmer. The corn which was
fed tested 44 per cent moisture at the Rochelle, Ill., elevator, and 20
cents per bushel was the best price offered for it.

Presumably on account of wet weather during the fall of 1915, the
sweet-clover seed crop was a failure in that section; in fact, the crop
had been cut for seed and part had been thrashed before it was decided
that the seed yield was not sufficient to pay for the thrashing. The
remainder of the crop was then run into the silo and fed to the steers.
The leaves fall and the stems of this plant become hard and woody as
the seed matures. The crop therefore would have been worthless for
feed had it not been placed in the silo. As a rule, stock readily eat
sweet-clover straw when the stems are broken and crushed by the hulling
machines. The sweet-clover straw which was used as roughage during the
first part of the feeding period was from that part of the seed crop
which had been thrashed.

An interesting feeding experiment was conducted on a farm at Rochelle,
Ill. On September 7, 1913, 29 head of 2-year-old steers, averaging
836 pounds, were turned on 40 acres of sweet clover which had been
seeded that spring with barley. These animals were pastured on the
sweet clover until November 1 without additional feed. During this time
they made exceptionally large gains. From November 1 to December 11,
28 head of these steers had access to an 80-acre field of cornstalks.
On December 11 they were put into the feed lot. During the time these
steers were on the cornstalks they barely held their gain, but during
the first 30 days they were in the feed lot they made an average daily
gain of almost 3 pounds. In this period they received 215 bushels of
corn-and-cob meal and 16-3/4 tons of silage made from the first-year
growth of sweet clover. During the next 30 days they received 388
bushels of corn-and-cob meal and much less sweet-clover, silage.
During this time they made an average daily gain of 2 pounds. When the
corn-and-cob meal ration was increased the steers ate less silage.
These cattle dressed 55-1/8 per cent at a Chicago packing house.




SWEET CLOVER AS A SOIL-IMPROVING CROP.


Unlike many legumes, sweet clover will make a good growth on soils too
depleted in humus for profitable crop production. In addition to its
ability to grow and to produce a considerable quantity of forage on
such soils, it will add much humus to them. The extensive root systems
do much toward breaking up the subsoil, thereby providing better
aeration and drainage. The effect of the large, deep roots in opening
up the subsoil and providing better drainage is often very noticeable
in the spring, as the land upon which sweet clover has grown for
several years will be in a condition to plow earlier than the adjacent
fields where it has not been grown. The roots are often one-eighth of
an inch in diameter at a depth of 3 feet, and they decay in five to
eight weeks after the plants die. (Figs. 12 and 13.) The holes made by
the roots are left partly filled with a fibrous substance which permits
rapid drainage. Sandy soils are benefited materially by the addition
of humus and nitrogen, while hardpan often is broken up so completely
that alfalfa or other crops will readily grow on the land. The roots
add much organic matter to the layers of soil below the usual depth of
plowing, while those in the surface soil, together with the stubble
and stems, when the crop is plowed under, add more humus than possibly
any other legume which may be grown in short rotations. Not only does
this crop add organic matter to the soil, but in common with other
legumes it has the power of fixing atmospheric nitrogen by means of the
nitrogen-gathering bacteria in the nodules on the roots.

[Illustration: Fig. 12.--A portion of a root of sweet clover, collected
30 days after the seed crop had been cut. The cortex was so decayed
that it remained in the ground when the root was removed. Note that the
pith has largely disappeared and that the half-rotten central cylinder
is all that remains.]

[Illustration: Fig. 13.--The same root shown in figure 12 after being
crushed between the thumb and forefinger. Illustrating how rapidly
sweet-clover roots decay after the plants die. The holes left in the
ground by the rapid decay of the roots facilitate drainage.]

The ability of sweet clover to reclaim abandoned, run-down land has
been demonstrated in northern Kentucky and in Alabama. In these regions
many farms were so depleted in nitrogen and humus by continuous
cropping with nonleguminous crops that profitable yields could be
obtained no longer, Through the use of this crop many of these farms
have been brought back to a fair state of fertility. Tests at the
Alabama Agricultural Experiment Station show that the increased yield
of corn following sweet clover which had occupied the land for two
years was 6-3/4 bushels per acre. The cotton grown on the land the
second year showed an increase of 56 pounds per acre. The combined
value of the increased yields of corn and cotton for the two years was
estimated at $9.75. The total yield of hay for the two preceding years
was 6.8 tons per acre. In another experiment at this station cotton was
planted on land that had grown sweet clover the two previous years and
on land that had received an application of 18 tons of stable manure
per acre. The sweet-clover plat produced 280 pounds of seed cotton the
first year and 120 pounds of seed cotton the second year more than the
plat which received the heavy application of manure.

Land on which sweet clover had been grown for four years at the Ohio
Agricultural Experiment Station yielded 26.9 bushels of wheat per acre
as compared with 18.6 bushels on the check plat. Sweet clover was
seeded at the Tennessee Agricultural Experiment Station in the spring
of 1912. One cutting of hay was removed that year and the following
spring the field was plowed and planted to corn. The corn yielded
58.8 bushels per acre as compared with 41.1 bushels per acre for an
adjoining plat where rye was turned under. A number of tests have been
conducted in southeastern Kansas which show clearly the value of sweet
clover as a soil-improving crop for that section. The yield of wheat
has been increased as much as 7 bushels per acre and that of corn as
much as 22 bushels per acre by plowing under the second-year growth of
clover.

Annual yellow sweet clover is rapidly gaining in favor as a
green-manure crop for orchards in the Southwest. In Arizona two plats
seeded in October and plowed under in April yielded, respectively, 16
and 17 tons of green matter to the acre. At the Arizona Agricultural
Experiment Station annual yellow sweet clover, lupines, and alfalfa
were tested as green-manure crops for orchards. In this experiment the
sweet clover clearly showed its superiority to lupines or alfalfa for
this purpose, as it yielded from 21 to 26 tons of green matter per
acre, whereas the highest yield for the lupines was 10 tons and for the
alfalfa 15 tons per acre.

The use of annual sweet clover as a green-manure crop in southern
California has increased very rapidly in recent years, and this
increased use apparently has been justified by the results obtained
with it. One of the most interesting green-manure tests thus far noted
was conducted at the California Citrus Experiment Station. In this
experiment nine legume plats and eight nonlegume plats alternated
with each other. The 4-year average weight of green matter produced
on the sweet-clover plat was 14-3/4 tons per acre, whereas the 5-year
average weight of green matter produced by common vetch and Canada
field peas was 12 tons and 9 tons, respectively, per acre. On one
series of these plats corn was planted in rotation with the clover.
The average yield of shelled corn for four years was 46 bushels to
the acre on the sweet-clover plat, as compared with 35 bushels to the
acre on the common-vetch plat and 40 bushels per acre on the field-pea
plat. One barley plat receiving each year an application of 1,080
pounds of nitrate of soda gave an average yield of 41 bushels per acre.
The 2-year average yield of potatoes following sweet clover was 252
bushels per acre, as compared with 171 bushels following common vetch
and 234 bushels following field peas. Sweet clover has proved to be an
excellent plant to grow in rotation with sugar beets, as the 2-year
average for the beets following it was 19.8 tons per acre, as compared
with 15.3 tons following common vetch, and 17.6 tons following field
peas.

Annual yellow sweet clover makes a profitable growth only in the South
and Southwest and therefore should not be planted in any other section
of the country.

In those sections of the United States where the soils are low in humus
it is to be strongly recommended that sweet clover be grown for green
manure. This method is being practiced in some sections of the country
with excellent results.

It should be remembered that sweet clover will not make a satisfactory
growth on acid soils and that it is very essential to provide
inoculation if the soil is not inoculated already.




SWEET CLOVER IN ROTATIONS.


As sweet clover is a biennial plant, it lends itself readily to short
rotations. It may be seeded in the spring on winter grain or with
spring grain, the same as red clover. It will produce at least as
much pasturage the following fall as red clover, and in some parts of
the country a cutting of hay may be obtained after the grain harvest.
The following year the plants will produce two cuttings of hay or one
cutting of hay and a seed crop. In some sections of the United States
this plant is replacing red clover in rotations, as it will succeed on
poorer soils than red clover and will add much more humus to the soil.
It will withstand drought better than either red clover or alfalfa,
and on this account its use in rotations may be extended into drier
sections. As a rule the beneficial effect of sweet clover on the
subsequent crops is more marked than that of other legumes. This is
especially true with corn, and whenever possible corn should follow
sweet clover in rotations. Root crops also are benefited by its use in
rotations, as the large deep roots of sweet clover open up the soil.




SWEET CLOVER AS A HONEY PLANT.


A number of the leading honey plants fail to secrete nectar in part of
the territory in which they are found, but white sweet clover ranks as
a valuable source of nectar wherever found in sufficient quantity in
the United States. The period of nectar secretion usually follows that
of white and alsike clovers in the Northern States, and consequently
comes at a time when the colonies are strong enough to get the full
benefit of the secretion. The honey from white sweet clover is light in
color, with a slight green tint, the flavor being mild and suggestive
of vanilla. The characteristic flavor and color of the honey seem to
be less marked during a rapid secretion of nectar, In the irrigated
portions of the West honey from white sweet clover is often mixed with
that from alfalfa.

Beekeepers have long recognized the value of sweet clover as a source
of nectar, and for years tons of seed have been sold annually by
dealers in beekeepers' supplies. It has never been found profitable
to cultivate any plant solely for nectar, and those beekeepers who
were primarily interested in the plant for bee forage have scattered
the seed chiefly in waste places and along railroad embankments and
roadsides. A number of beekeepers who were also engaged in general
farming have for years utilized the plant for forage, and they were
among the earliest to grow the plant for seed, so as to be able to
supply their fellow beekeepers. Sweet clover to-day is almost the
only plant which beekeepers seek to increase in waste lands in their
localities.

The yield of nectar from sweet clover is heavy, and a number of
beekeepers now market this honey in carload lots. Sweet clover is
utilized for honey especially in Kentucky, in Iowa, and in Colorado and
adjacent States. In Alabama and Mississippi a number of beekeepers are
harvesting large crops chiefly from this source. The color and flavor
make this plant suitable for either comb or extracted honey.

Yellow sweet clover is perhaps as valuable for nectar as white sweet
clover, but beekeepers have paid less attention to it. This is probably
due to the fact that the blooming period of the yellow species often
coincides with that of white and alsike clover, making it less valuable
to the beekeeper. In sections where the quantity of white and alsike
clover is limited and it is desired to plant sweet clover for bee
pasturage, a mixture of the white and yellow species is recommended, as
the yellow species will bloom from 10 to 14 days earlier than the white.

Wherever any of the species of sweet clover are cultivated, either
for forage or for seed, beekeeping is to be recommended as a valuable
source of additional income, and such locations are especially suitable
for extensive commercial beekeeping.


       *       *       *       *       *


Transcriber Note


Minor typos may have been corrected. Illustrations may have been moved
to avoid splitting paragraphs. Many of the Tables have labels which are
displayed as italics; but due to space limitations in the text-only
version, the italicization was ignored.





End of Project Gutenberg's USDA Farmers' Bulletin No. 820, by H. S. Coe