Title: USDA Farmers' Bulletin No. 836 - Sweet Clover: Harvesting and Thrashing the Seed Crop
Author: Coe, H. S.
Language: English
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Transcriber Note

Text emphasis is denoted as _Italics_. Whole and fractional parts of
numbers as 123-4/5.



SWEET CLOVER

HARVESTING AND THRASHING THE SEED CROP


H. S. COE

Assistant Agrononmist, Office of Forage-Crop Investigations


[Illustration]


FARMERS' BULLETIN 836 UNITED STATES DEPARTMENT OF AGRICULTURE


Contribution from the Bureau of Plant Industry

WM. A. TAYLOR, Chief



  Washington, D. C.                    July, 1917


  Show this bulletin to a neighbor. Additional copies may be obtained
  free from the Division of Publications, United States Department of
  Agriculture

  WASHINGTON : GOVERNMENT PRINTING OFFICE : 1917


SWEET CLOVER should be cut for seed when three-fourths of the seed pods
have turned dark brown to black. At this time some flowers and many
immature pods will be found on the plants, but the field will have a
brownish cast.

Sweet-clover seed pods shatter badly when mature. For this reason every
precaution should be taken to cut the plants at the proper stage and to
save as much of the shattered seed as possible.

Shattering may be reduced to a minimum by cutting the plants when they
are damp from rain or dew.

No machine thus far placed on the market has given entire satisfaction
in cutting sweet clover for seed.

The ordinary mower should not be used for harvesting the seed crop. The
seed crop is usually cut with a self-rake reaper, grain binder, grain
header, or corn harvester. The self-rake reaper and the grain binder
have been most satisfactory.

The seed crop should be stacked unless it can be thrashed within two
weeks after cutting.

Much shattered seed will be saved if a wagon with a tight floor is used
for hauling the plants. If the wagon bed is not tight it should be
covered with a tarpaulin or canvas.

The seed may be flailed from the plants, as is customary in the South,
or it may be thrashed with a grain separator or clover huller, as is
the practice in the North.

The ordinary grain separator may be adjusted so that it will hull 90
per cent of the seed.

Sweet-clover straw has considerable feeding value.



SWEET CLOVER: HARVESTING AND THRASHING THE SEED CROP.[1]

[1] This bulletin discusses only the harvesting and thrashing of the
sweet-clover seed crop. The growing of sweet clover and its utilization
are discussed in Farmers' Bulletin 797, entitled "Sweet Clover;
Growing the Crop," and Farmer's Bulletin 820, entitled "Sweet Clover:
Utilization," respectively.



CONTENTS.


                                                   Page.

  The crop to harvest for seed                        3

  Time to cut the seed crop                           4

  Loss of seed from shattering                        4

  Machinery used for harvesting the seed crop         5

  Stacking the sweet-clover seed crop                17

  Thrashing the sweet-clover seed crop               18

  Yields of sweet-clover seed                        21

  Sweet-clover straw                                 23



THE CROP TO HARVEST FOR SEED.


White sweet clover and biennial yellow sweet clover are harvested for
seed the year following seeding. In localities where those species will
produce two cuttings the second year, either the first or the second
crop may be harvested for seed. As the plants die when mature, only one
cutting will be obtained if the first crop is permitted to ripen. It is
becoming a general practice in many sections of the country to utilize
the first crop of the second season for pasture, ensilage, or hay, and
the second crop for seed. As a rule, this is the most profitable and
economical way to handle sweet clover, as the first crop will produce
an abundance of nutritious pasturage or from 6 to 10 tons of ensilage
or 1 to 3 tons of hay to the acre. The second crop seldom grows more
than 4 feet high when the first crop is pastured or cut. The shorter
growth of the second crop is a very desirable feature, as it may be cut
with a grain binder without difficulty. When the first crop of white
sweet clover is permitted to mature, the plants often make so large
a growth that it is very difficult to handle them with ordinary farm
machinery. This trouble is experienced more often in humid regions than
in semiarid sections.

As biennial yellow sweet clover seldom grows as tall as the white
species, little difficulty is experienced in cutting the first crop
of the second year for seed with a grain binder. Annual yellow sweet
clover, or sour clover, is seldom grown for seed, as a sufficient
quantity to supply the market is obtained from the screenings of wheat
grown in the Southwest.

Sweet-clover seed ripens irregularly and shatters badly when mature. On
this account much seed is lost before and during harvest, and ordinary
harvesting machinery has not been entirely satisfactory for handling
the crop.



TIME TO CUT THE SEED CROP.


Opinions of extensive growers of sweet clover differ as to the proper
stage at which to cut the seed crop. Some believe that it should be cut
when the pods on the lower branches have turned dark brown to black,
while others maintain that it is best to wait until the seed on the
upper portions of the plants is mature. The time of cutting the seed
crop should be governed largely by the machinery which is to be used.
If the plants are to be harvested with a self-rake reaper or a grain
binder, they should be cut when approximately three-fourths of the
seed pods have turned dark brown to black. At this time some flowers
and many immature pods will be found on the plants, but the field will
have a brownish cast. If the crop is not cut until the seed pods on the
uppermost branches have matured, most of the pods on the lower branches
will have shattered.

It is the practice in regions where a grain header is employed to
permit the plants to become somewhat more mature before cutting the
seed crop than in sections where other machines are used. More seed
is shattered when the plants are cut at the latter stage, but this is
not necessarily a loss, as the grain header is employed for the most
part in semiarid regions, where the shattered seed is depended upon to
reseed the land.



LOSS OF SEED FROM SHATTERING.


From one-fifth to three-fourths of the total seed yield of sweet clover
is lost from shattering. The percentage of the loss which occurs before
harvesting will depend largely on the time the crop is cut. Much seed
may be lost if harvesting is delayed for only a few days, and many
fields have been observed in which at least 90 per cent of the seed had
shattered in less then two weeks after the time the plants should have
been cut.

The percentage of seed which is lost in harvesting will depend largely
upon the manner of handling the crop. The binder or header may be
equipped at a small cost, so that much of the seed which ordinarily is
lost while cutting may be saved. Much shattered seed will be saved by
using wagons with tight platforms or platforms covered with canvas. All
unnecessary handling should be avoided.

Shattering may be reduced to a minimum by cutting the plants when they
are damp from rain or dew. It is the practice in some regions to cut in
the early morning or late evening, but this procedure will apply only
to small acreages, since it is necessary to cut the crop as soon as
possible when it reaches the proper stage for harvesting. It is a good
practice to cut sweet clover at night, as the plants usually are damp
at that time.



MACHINERY USED FOR HARVESTING THE SEED CROP.


No machine thus far manufactured has given entire satisfaction for
cutting the sweet-clover seed crop. On account of the ease with which
the pods shatter, it is a question whether any machine can be devised
which will handle this crop without the loss of some seed. It is
possible and practicable, however, for farmers at a small cost to equip
their binders with pans and guards, so as to save most of the seed
which otherwise would be lost.


THE ORDINARY MOWER.

The ordinary mowing machine is one of the most unsatisfactory devices
used for harvesting this crop, as the subsequent handling necessary
to place the plants in windrows or cocks causes much of the seed to
shatter. The use of this machine for this purpose should be avoided
whenever possible.


THE SELF-RAKE REAPER.

The self-rake reaper is one of the most efficient machines employed to
cut sweet clover for seed. (Fig. 1.) This machine deposits the newly
cut plants with the tops all turned one way in gavels or bunches at the
side, so that the horses do not trample them on the next round. A high
stubble also may be left, thereby reducing the weight and bulk of the
plants which must be hauled to the thrashing machine.

[Illustration: Fig. 1.--A self-rake reaper used in some sections of the
country for cutting the sweet-clover seed crop.]

[Illustration: Fig. 2.--A sled used in western Kansas for hauling sweet
clover from the field to the thrashing machine.]

It is the custom in some localities to leave the gavels to cure as
dropped by the reaper on the ground, while in other sections they are
placed in cocks that weigh about 300 pounds each when cured. If the
gavels are to be placed in cocks, this should be done immediately after
cutting, as the plants will be somewhat green and tough at this time
and fewer pods will shatter than when the plants are permitted to dry
before handling. When the crop is to be hauled to the thrashing machine
on wagons it is best to permit the gavels to cure as dropped by the
reaper, as it will then be possible to pitch them on the wagon with
a large 4-tined fork. If the crop is to be hauled to the thrashing
machine on large sleds, which is the practice in western Kansas, less
seed will be lost from shattering if the gavels at the time of cutting
are placed in cocks of such a size that they may be put on the sleds
entire by two men lifting from opposite sides of the cock with 4-tined
forks. The sleds used for this purpose usually are 12 by 20 foot in
size, made of matched flooring and with 6 to 12 inch sides. (Fig. 2.)
Matched or tight floors are necessary, so that all seed which shatters
may be saved. These would not be so essential, however, if the sleds
were covered with a tarpaulin or canvas. From the standpoint of saving
shattered seed, this method of hauling the crop from the field to the
thrashing machine is possibly the most economical thus far used. It
is estimated that at times as much as one-third of the seed yield is
collected from the floors of the sleds. It would be a good plan to
replace the runners of the sleds with very low trucks, as this would
lighten the draft considerably.

When sweet clover is cut with a self-rake reaper the crop is thrashed
directly from the field. From 7 to 10 days of good haying weather in
sufficient to cure the plants in the gavel or cock. Thrashing should
be done as soon as possible, much seed is shattered by rains and
winds. While a self-rake reaper is used to some extent in different
sections of the country, it is used most extensively in the western
North-Central States, and especially in western Kansas.


THE GRAIN BINDER.

A grain binder is employed extensively for cutting the sweet-clover
seed crop. (Fig. 3.) The general use of this machine in many sections
of the country is due to the fact that it is found on most farms
and therefore causes no outlay of money, rather than because of its
efficient work. It is not so efficient as the self-rake reaper unless
it is equipped with pans and guards to save the seed which shatters.

[Illustration: Fig. 3.--Cutting sweet clover for seed with a grain
binder.]

It is possible to equip the grain binder with pans and extensions to
the rear elevator plate and binder deck, so that at least 95 per cent
of the seed which shatters when the crop is cut may be saved. Those
pans and extensions may be made out of ordinary galvanized metal and
strap iron. The galvanized metal may be purchased at any tin shop or
hardware store, and if sufficient strips of iron can not be found
around the farm for this purpose strap iron may be purchased at any
blacksmith shop. The material for those pans and extensions should not
cost more than $4.50 or $5, and it should be possible to have them
made complete for $8 or $10, including material. Unless there are a
forge and drill on the farm it will be necessary to have the braces
and supports for the pans made at a blacksmith shop. The strap iron
used in connection with the pans may vary in size, but for the most
part it need not be heavier than one-eighth inch in thickness, and
seven-eighths inch in width. The supports for the pan under the binder
deck preferably should be one-quarter inch thick, as this pan will have
much more strain on it than the pans under the elevators. Where bolts
are to be used, ordinary stove bolts will suffice.

[Illustration: Fig. 4.--Plans for a pan to be placed under the opening
between the platform and lower elevator of a grain binder in order
to save the sweet-clover seed which falls on the platform and on the
extension to the rear elevator plate. _A_, size and shape of the metal
before bending; _B_, general plan of the pan when completed, as viewed
from the top; _C_, cross section of the pan and outline of the support
which holds it in position; _D_, stirrup which hooks over the inside
and to which the support is fastened; _E_, door.]

[Illustration: Fig. 5.--Rear view of a grain binder, showing a cross
section of the pans and supports and the parts of the machine to which
they are attached. _A_, Pan under the opening between the platform and
lower elevator; _B_, support of the pan; _C_, stirrup which fits over
the inside sill and to which the support is bolted; _D_, angle iron
under the end of the platform and over which one end of the support is
hooked; _E_, cross section of pan under the binder deck; _F_, support
of the pan; _G_, stirrup which hooks over the outside sill and to which
the support is bolted; _H_, angle iron which supports the guard at the
end of the deck; _I_, guard which directs the seed that falls on the
binder deck into the pan below; _J_, binder pipe over which one end of
the support is hooked.]

The plans for making the pan which should be placed under the opening
between the platform and the lower elevator are illustrated in figure
4. The material to be used for this pan should be cut to conform to the
size and shape shown in figure 4, _A_; the sides should then be bent
upright along the dotted lines, so that the pan will be 18 inches wide
at the top. One end, which should be solid, may be made so by bending
the center portion upright and then bending the sides against it. The
side and center pieces should be riveted together. (Fig. 4, _C_.) Any
suitable door which will prevent seed from falling out of the pan will
suffice for the other end. A door is highly desirable, so that the seed
may be removed more easily when the pan is full. A convenient type is
shown in figure 4, _E_. A top view of the pan when completed is given
in figure 4, _B_. It will be necessary to brace the pan, and this may
be done by riveting strips of strap iron, preferably one-eighth inch
thick and one-half inch wide, on the outer edges of the sides.

This pan is held in position by two supports made of strap iron,
preferably seven-eighths inch wide and one-eighth inch thick, which
have been bent to conform to the outside of a cross section of the pan.
(Figs. 4, _C_, and 5, _B_.) The ends of these supports which fasten
under the platform should be bent to a sharp angle and the tip of each
slightly flattened, so that they may be pushed between the angle bar
at the end of the platform and the bottom of the platform. The other
end of each support should have a hole drilled in it, so that it may be
bolted to the stirrups, which should be made to hook over the inside
sill. (Figs. 4, _C_, and 5.) These supports should be placed about
6 inches from the ends of the pan and riveted or bolted to it. This
will serve to brace the pan and to hold it in place. The pan may be
attached to the machine by hooking the supports over the angle iron on
the bottom of the platform and by bolting them to the stirrups on the
sill. By supporting the pan in this manner it may be easily and quickly
attached or removed.

[Illustration: Fig. 6.--Plans for the pan to be placed under the binder
deck of the grain binder. _A_, Size and shape the metal should be cut
before bending; _B_, general plan of the pan when completed, as viewed
from the top.]

[Illustration: Fig. 7.--Plans for the guard to be placed at the end of
the binder deck of the grain binder and cross section of the pan and
supports illustrated in figure 6. _A_, Size and shape of the metal for
the guard; _B_, shape of the guard when completed; _C_, cross section
of the pan and support to which this guard is attached; _D_, angle iron
which supports the guard at the end of the deck; _E_, guard bolted in
position; _F_, stirrup which hooks over the outside sill and to which
the support is belted.]

The pan to be placed under the deck of the machine will serve to
collect the seed which is shattered on the deck and the extension to
the deck. The plans for making this pan are shown in detail in figure
6. The material should be cut along the solid lines and of the size
designated in figure 6, _A_. The sides of the pan should be bent upward
on the dotted lines, so that the pan will be 24 inches wide at the
top. The ends should then be made in the manner described for the pan
which is placed under the opening of the platform and lower elevator.
A door may be put in the rear end of this pan if desired; but this
is not necessary, as no trouble will be experienced in removing the
seed. Figure 6, _B_, gives a top view of the pan when completed and
also a portion, of the guard which serves to direct into this pan the
seed which shatters on the deck. This guard is shown in detail in
figure 7. As this pan is larger and heavier than that placed under
the lower elevator, not only should it have strips of iron riveted
to the outer edges of the sides, but two cross braces also should be
employed. Those may be fastened to the strips of iron supporting the
sides of the pan and should be about 12 inches from the ends of it.
This pan is supported by two strips of strap iron bent to conform to
the outside of a cross section of it and hook over the binder pipe
under the deck and bolt to stirrups placed on the outer sill of the
frame. Each support may be made from one strip of strap iron. It may be
necessary to bend the ends of the supports which hook over the binder
pipe in opposite directions. Both ends of the supports which hook over
the binder pipe may hook outward, as shown in figure 7, _C_, or the
rear support may hook inward, as illustrated in figure 5. It is not
absolutely necessary that those supports of the pan hook in opposite
directions on the binder pipe, yet when this is done it will make the
pan more rigid. The pan may be attached by first hooking the supports
over the binder pipe underneath the deck and then bolting the other end
of the supports to the stirrups on the outer sill. The pan should be
fastened to the supports. A cross section of this pan, the supports for
it, and the stirrups which hook over the sill are shown in figure 7,
_C_.

If this pan extends beyond the deck so that the seed which is shattered
on the deck will drop directly into it, the bundles when released from
the packers will strike the pan. For this reason it is necessary to
place a guard at the end of the deck, so that the seed which falls on
the deck will be directed into the pan. This guard, as shown in figures
5 and 7, consists of a piece of galvanized metal, to the upper side of
which has been riveted a strip of iron. The upper side of this guard
should be bent slightly inward at the lower edge of the strip of iron
and placed in such a position that it will be approximately 1-1/2
inches beyond the lower end of the binder deck and extend from 1 to
1-1/2 inches above the deck. If it is placed at right angles to the
deck and no higher than 1-1/2 inches above it, it will not interfere
with the bundles as they are released from the packers. This guard
should be supported by two angles of strap iron, as shown in figure 7,
_D_. Those braces are bolted to the supports of the pan, and the guard
is bolted to the braces. As this guard should extend a little below the
supports of the pan, so as to prevent the wind from blowing the seed
over it, it is necessary to cut slots in the guard so it will fit over
the supports. The ends of this guard should be rolled slightly inward,
so that the seed falling close to them will be directed into the pan.
When the extension to the binder deck is placed in the proper position,
the seed collected by it will be directed against the guard and then
into the pan below.

The extension to the elevator should be bolted to the rear elevator
plate. This extension should be so wide that the tops of the plants
will not reach beyond it. The details for this extension are shown in
figure 8. The outer edge and lower end of this extension should be bent
upward and slightly inward, so that the seed which falls upon it will
be directed to the opening between the platform and lower elevator,
where it will fall into the pan beneath. The curved edge of the lower
part of this extension should be flattened as much as possible, so
that it will not interfere with the upper portions of the plants as
they pass from the platform to the elevators. The opening must be
sufficiently large, however, to permit small branches and racemos which
fall upon the extension to pass into the pan. The angle of the lower
portion of it must be large enough to permit the seed to run directly
into the pan below. If this portion is sloped from the seat pipe to the
opening between the platform and the lower elevator no trouble will be
experienced. This extension may be bolted to the machine by drilling
holes in it to coincide with those in the elevator plate.

[Illustration: Fig. 8.--Plan of the extension which is bolted to the
rear elevator plate of the grain binder. _A_, Size and shape of the
metal to be used for this extension; _B_, extension when completed.]

It is necessary to widen the binder deck, so as to save the seed which
is shattered from those portions of the plants which extend beyond it.
This may be done by bolting to the rear end of this deck an extension,
as shown in detail in figure 9. This extension may be made from one
piece of galvanized iron, which should be cut along the solid lines
and of the size shown in figure 9, _A_. It should be bent upward and
slightly inward at the dotted lines shown in this figure. The extended
strips, as shown in figure 9, _B_, should be riveted to the main part
of the extension. When this is done a trough will be formed along the
side and lower end of it, so that all seed which shatters upon it will
be directed into the pan below the deck. The object in riveting the
extended strips at the end of the extension to the main part is to
prevent the tops of the plants from catching in the trough when the
bundles leave the packers. It may be necessary to fasten a brace to
the bottom of the deck to support this extension. This can be done,
however, by using a strip of strap iron or wood. The upper end of
this extension should be bent to fit under the upper end of the one
attached to the elevator plate, so that the plants will not be hindered
in passing from one to the other. Both extensions may be braced
strongly at the top by fastening them to a right angle of iron or wood.

A grain, binder equipped with the pans and extensions herein outlined
is shown in figure 10.

Binders equipped in the manner described have been tested carefully
in different sections and have proved beyond doubt that they offer an
economical device for harvesting sweet clover for seed. This equipment
has been used most extensively in Livingston County, Ill., where
farmers have saved with it from $6 to $10 worth of seed per acre. When
this equipment is used the plants may be permitted to become somewhat
more mature before cutting, as the seed which is shattered will be
saved by the pans.

[Illustration: Fig. 9.--Extension to the binder deck of the grain
binder. _A_, size and shape of the metal before bending; _B_, extended
points which are to be bolted to the main portion of the metal; _C_,
extension when completed.]

As the pans and extensions described have been designed for one type of
binder, it may be necessary to modify them slightly for use on other
types of machines. Before making a set of these pans and extensions
for any machine, the plans shown should be compared carefully with the
binder to be equipped, in order that any changes which will need to be
made may be noted. The pans and extensions at least maybe made on the
farm, and then it will be an easy matter to check up the measurements
for the supports, which may be made at a blacksmith shop.

Difficulty may be experienced in cutting sweet clover with a binder
when the first crop has been permitted to mature, as the plants may
be so tall that the machine will not handle them properly. This
difficulty may be overcome entirely in most sections of the country
by pasturing the field until the first part of June or by cutting the
first crop for hay. It is recommended that the stubble be left as high
as possible when cutting sweet clover for seed. Not only will this
greatly facilitate harvesting but it will leave many of the woody,
unpalatable portions of the plants on the ground, where they will decay
quickly, and help to increase the humus content of the soil. (See the
illustration on the title-page.)

When the seed crop is cut with a binder it is best to shock the bundles
as soon as possible, so as to avoid unnecessary shattering. Conditions
should determine whether the bundles be placed in long narrow shocks or
in round shocks. The plants will cure somewhat faster in long narrow
shocks, and this form should be preferred when grasshoppers are not
troublesome. Sweet-clover shocks should not be capped, as capping will
cause some seed pods to shatter.

[Illustration: Fig. 10.--A grain binder equipped with pans and
extensions to the rear elevator plate and binder deck to save the
sweet-clover seed which is shattered while cutting the crop.]


THE GRAIN HEADER.

Grain headers have been used successfully for harvesting the
sweet-clover seed crop in several sections of the United States,
especially in western Kansas. The principal advantages in using this
machine are that a larger acreage may be cut in a given time than with
either a grain binder or a self-rake reaper and that a high stubble
may be left. The greater acreage which may be cut with a header is
important when large acreages are to be harvested, as much seed is
lost by shattering if the crop is not cut at the proper stage for
harvesting, while the high stubble which may be left when cutting
the seed crop with a grain header is a decided advantage, as it not
only reduces greatly the weight and bulb of the plants which must be
thrashed, but it also leaves the hard, woody portions on the ground,
where they will decay and be of some value as a fertilizer. It is best
to remove only those portions of the plants which contain sufficient
seed to thrash, but this is not always possible, even with a header,
unless the field contains a fairly thin stand and the plants are not
more than 4-1/2 to 5 feet high. When the seed crop is to be cut with
a grain header, it usually is permitted to stand somewhat longer than
when other machines are used.

A tin pan or some other receptacle should be placed at the lower end of
the header elevator in order to save the seed which otherwise would be
lost at that place.

The plants are carried into header wagons or barges in the same way
as grain. When a heavy crop is cut it will be necessary to have two
men in the barge to handle the plants. The floor of the header wagon
should be made perfectly tight, or it should be covered with a canvas
or tarpaulin, so as to save the seed pods which shatter.

When the crop is cut at the proper stage it may be placed directly in
stacks or ricks without danger of heating or molding, provided the
ricks are covered or topped with some material which will shed water
and are built upon a foundation, so that air may circulate under them.
Native grass or green sweet-clover plants of the first year's crop will
serve very nicely for topping the stacks.

It is the custom of some people to place the barge loads close together
in individual stacks so located that they may be hauled quickly and
easily to the thrashing machine. On other farms enough barge loads
are placed together to make a rick approximately 10 by 10 by 40 feet
in size. When each barge load is placed in a separate stack it is
necessary to load the plants again, so as to haul them to the thrashing
machine. The shattering of seed pods and the extra labor caused by
reloading and by hauling the plants may be avoided for the most part
by placing the crop in ricks large enough for a day's thrashing. It is
good practice to place such ricks in pairs sufficiently close together
for both to be pitched directly to the feeder of the machine. When this
method is employed two days' thrashing may be done without moving the
machine.

The header binder, consisting of an attachment placed upon the header
to bind the cut plants, has been used successfully in cutting the
sweet-clover seed crop.


THE CORN HARVESTER.

Corn harvesters are proving to be efficient machines for cutting sweet
clover which has made a growth too large to be cut with a grain binder.
Even when the field has been seeded broadcast a 3-foot swath may be cut
with the corn harvester, provided the gathering or divider points are
extended to collect the plants. This may be done by fastening to each
point a piece of wood or iron about 18 inches long. When a corn binder
is used no more seed is lost from shattering than when an ordinary
grain harvester is employed, unless the later is equipped with special
pans and extensions, for the reason, primarily, that the portions of
the plants which produce most of the seed extend above the gathering
or divider boards and are not crushed. When a 5-foot or larger growth
is cut with a corn binder, the plants are tied below the seed-bearing
branches.

In the semiarid sections of the country a limited quantity of sweet
clover is planted in rows for both forage and seed production. In such
a case the seed may be harvested with a corn binder. (Fig. 11.)

[Illustration: Fig. 11.--Cutting sweet clover for seed with a corn
harvester. This field had been seeded in 30-inch rows.]



STACKING THE SWEET-CLOVER SEED CROP.


Much discussion has taken place among extensive growers of sweet clover
as to the advisability of stacking the seed crop after it is cut with a
grain binder or a corn harvester. The conditions present in each case
should determine the proper course to pursue. If it will be impossible
to thrash within 10 days after cutting, much less seed will be lost by
stacking two or three days after cutting than by permitting the plants
to remain in the field subject to possible rains. In such cases it is
urged that the crop be stacked, as the seed saved by this operation, if
the handling is done with care, will much more than pay for the labor.
When it is possible to thrash in a week or 10 days after cutting,
the crop should be thrashed directly from the field, as little seed
ordinarily will be lost during this time and the work of stacking will
be avoided.

When the crop is to be stacked, the stacks should be built in the same
way as stacks of grain; and when properly built they will shed water
as well as grain stacks. (Fig. 12.) It is well, however, to provide a
covering, and if canvas is not available a top-dressing of green grain
or young sweet-clover plants will suffice. Sweet clover should remain
in the stack for three or four weeks, as it will require about that
time for the plants to pass through the sweat. A stack should always
be placed on high ground, where water will not collect about the base,
and it is recommended that a foundation of some kind be provided, so
that air may circulate beneath. A few posts or rails will answer this
purpose very well.

[Illustration: Fig. 12.--A stack of sweet clover.]



THRASHING THE SWEET-CLOVER SEED CROP.


Two methods are in general use for thrashing the sweet-clover seed
crop. The seed may be flailed from the plants, or it may be removed by
a grain separator or a clover huller.


FLAILING THE SEED.

Much of the sweet-clover seed harvested in the South is flailed from
the plants. This method is necessarily slow and does not hull the seed.
It is practicable, therefore, only in regions where the necessary
machinery for hulling the seed crop is not available or where the
acreage to be thrashed is very limited. One advantage of thrashing the
seed in this manner is that the straw is left in the field, where it
will add much organic matter to the soil.

When the seed is to be flailed, the crop ordinarily is cut with a
scythe or mowing machine and the plants raked into piles or windrows.
If only small areas are to be harvested in this manner, a canvas or
tarpaulin may be spread on the ground beside a windrow or pile and
several forkfuls of sweet clover pitched on the canvas, where the seed
may be removed from the plants by striking them a few times with
flails, sticks, or forks. After the plants have been struck a few times
they should be turned over and struck again. When the seed is removed
front the plants, the straw may be pitched to one side, the canvas
placed beside another portion of the windrow or by another pile, and
the operation repeated. It is not necessary to remove the seed from the
canvas until its weight or bulk interferes with moving the canvas.

It is the practice in some sections of the country to place a
well-braced frame, covered with wire netting, on a sled and to flail
the seed on this frame. The netting used for covering the frame should
have meshes 1 inch or loss in diameter. The sled should be at least 7
feet wide and 10 feet long and should have sides and ends approximately
12 inches high. Smaller sleds sometimes are used, but a larger one is
to be preferred if two or more persons are to flail on it at one time.
If the floor of the sled is not perfectly tight, it should be covered
with canvas and the edges of the canvas thrown over the sides and ends
of the sled, so as to avoid losing any of the seed and to facilitate
its removal. A sled so equipped may be drawn from pile to pile, the
plants pitched on it, the seed flailed from them, and the straw
returned to the land for soil improvement.

Another method, very similar to that just described, is to place a
frame on a hayrack. The frame should be built sufficiently strong and
in such a manner that the person who is to do the flailing may stand
on it. It should be covered preferably with galvanized-wire netting
having half-inch meshes, and if this is stretched tightly it will
serve to strengthen the frame. If it is not practicable to make the
hayrack perfectly tight, it should be covered with a tarpaulin or
canvas. A wagon so equipped may be pulled from pile to pile or along
the windrows, where one person may pitch the plants upon the frame, to
be flailed by one or more persons standing on it. After the seed is
removed from the plants, the straw may be scattered easily and quickly
over the ground for soil improvement.

Flailed seed should be cleaned thoroughly with sieves and fanning
mills to remove the inert matter and immature pods before it is sown
or offered for sale on the market. It is recommended that whenever
possible unhulled seed be run through a clover huller to hull the seed
or through an Ames hulling and scarifying machine to remove the hulls
and to scarify the seed. By this process the outer coat of the seed
is scratched or broken. The scarifying increases the percentage of
germination by facilitating the entrance of moisture.

[Illustration: Fig. 13.--Thrashing sweet clover with a grain separator.
Note the large sleds used for handling the plants from the field to the
thrashing machine.]


THE GRAIN SEPARATOR.

A grain separator (fig. 13) is used more than any other machine for
thrashing sweet clover. This is because more grain separators than
clover hullers are found in localities where sweet clover is grown
and because the ordinary clover huller will not handle a large growth
of sweet clover satisfactorily. When the grain separator is operated
carefully no trouble should be experienced in removing the seed from
the plants, but it is necessary to make certain adjustments if the
seed is to be hulled. The adjustments required will vary somewhat with
the make of machine and the dryness of the crop. The riddles should be
adjusted or changed so they will handle sweet-clover seed properly.
Alfalfa or red-clover riddles will answer this purpose. The speed of
the fan should be decreased, so the seed will not be blown over, and
this usually will be accomplished when the speed is reduced to about
one-half that used in thrashing grain. The number of rows of concave
teeth which should be used will vary with the dryness of the plants
and somewhat with their size. When it is not desired to hull the seed,
one or two rows of concave teeth will be sufficient. Some operators
believe that one or two rows are sufficient to hull 40 to 50 per cent
of the seed when the plants are very dry. Those are exceptional cases,
and hulled seed should not be expected unless more rows of concave
teeth are used. If hulled seed is desired it is recommended that a
full set be used and that these be set to run closer to the cylinder
teeth than is customary when thrashing grain. Some operators replace
two rows of the smooth, concave teeth with corrugated teeth. This
practice is recommended wherever possible, as the corrugated teeth will
facilitate greatly the hulling of the seed. Even where these changes
are made, only a small percentage of the seed will be hulled if the
pods are damp. If the plants have been permitted to make a very large
growth the machine may clog unless the number of rows of concave teeth
is reduced. Clogging may be overcome for the most part by feeding the
bundles to the machine slowly. This precaution is necessary regardless
of the size of the plants if the seed is to be removed properly and
hulled. It is possible to hull from 90 to 95 per cent of the seed when
the proper adjustments are made and the plants are dry.

A clover-hulling attachment, which consists for the most part of
special sieves and a number of rows of corrugated concave teeth which
replace the ordinary concave teeth, has been used with success in
different sections of the country.


THE CLOVER HULLER.

As a rule, ordinary clover hullers do not handle sweet clover very
satisfactorily. Machines with cylinders larger than those commonly used
are giving fair satisfaction provided the plants do not make a large
growth, but even these machines have not been so successful as properly
adjusted and equipped grain separators. A clover huller will handle a 2
to 3 foot growth of sweet clover if the rows of thrashing concaves are
reduced and the plants are fed slowly to the machine. It will not hull
sweet clover as well as red clover, and it is very doubtful whether
it will hull more seed than a grain separator equipped with a hulling
attachment.

The manufacturer of at least one clover huller has designed special
rasps for the hulling cylinder and concaves of his machine, and these
rasps do better work than the ones ordinarily used for hulling red
clover.

It is the custom in some localities to run the sweet clover through a
thrashing machine without adjusting the concaves and then to run the
unhulled seed as delivered by the grain separator through a clover
huller. A fair quality of seed may be obtained by this process, but
it calls for much extra labor and time, and for this reason should be
avoided Whenever possible.



YIELDS OF SWEET-CLOVER SEED.


Many factors besides shattering influence the yield of sweet-clover
seed. As only those portions of the plants exposed directly to the
sunlight set seed abundantly, thin stands usually produce more seed to
the acre than heavy stands. When very heavy stands make a large growth,
seed is produced only on the upper 24 to 30 inches of the plants,
whereas with thinner stands it is produced on the lower branches as
well.

The quantity of moisture in the soil at the time the seed is maturing
is an important factor also. During hot, dry weather the plants may not
be able to absorb from the soil sufficient water to supply the excess
required by them for seed production. In this event many of the seed
pods will abort and fall when partly mature. Pods abort and fall in
a very short time, so that partly shriveled ones seldom are found on
the plants, although the extent of the aborting is shown by the number
of barren racemos. When such weather conditions prevail, the second
crop usually will produce a heavier yield than the first crop. This is
due for the most part to the inability of the large plants to obtain
sufficient water for seed production. The much smaller plants of the
second crop do not require as much moisture as the larger plants of the
first crop, as the vegetative growth is seldom more than half as much.

The type of root growth has much to do with the quantity of water the
plants are able to obtain during droughty weather. When sweet clover is
planted on soil that has a tendency to be wet, the plants will produce
a much-branched shallow root system instead of the normal deep roots
which are found on well-drained soils. During dry weather the upper
layers of soil become so depleted that plants having a very large
percentage of their roots in these layers can not obtain a sufficient
quantity of moisture to supply their requirements for seed production.

It is often stated that the first crop of sweet clover will produce
more seed to the acre than the second crop. This depends very largely
upon the thickness of the stand and on weather conditions. In regions
where two crops may be grown in a season, the first usually will
produce more seed to the acre than the second if the field has a thin
stand. When the stand is thick the second crop ordinarily yields more
seed. In regions where a crop of hay or pasturage may be obtained in
addition to the seed crop, it is seldom an economical procedure to
permit the first crop to mature. Not only will sweet clover produce an
abundance of nutritious pasturage or a cutting of 1 to 3 tons of hay in
addition to the seed, but the difficulty of handling the large, stemmy
growth of the first crop for seed is avoided.

Yields of sweet-clover seed have been reduced during the last two
seasons by several fungous diseases. Experimental work has not been
completed to show the percentage of damage done by these organisms, but
in some sections of the country seed yields were reduced considerably.
The clover stem borer,[2] which is prevalent in red clover in certain
sections of the country, also infests sweet clover. It is probable that
this insect did some damage to the seed crop in certain sections of the
country in 1916.

[2] Languria mozardi.

The yield of sweet-clover seed varies from 2 to 10 bushels of
re-cleaned seed per acre.



SWEET-CLOVER STRAW.


Sweet-clover straw may be utilized for soil improvement or as a
roughage for stock. When it is not needed for feeding it should be
turned under, as it will add much humus and nitrogen to the soil.
When the seed is flailed from the plants the straw may be easily and
quickly spread over the land at the time of flailing, but when the
crop is thrashed with a grain separator or a clover huller it will be
necessary to haul the straw and scatter it over the field. When the
crop is thrashed in this manner the straw will be broken and crushed
so that stock will eat it freely. The straw may be run directly from
the thrashing machine into the silo, where, by adding sufficient water,
it can be made into good silage. Table I gives the analyses of nine
samples of sweet-clover straw which were collected in Illinois in the
fall of 1916.


Table I.--Analyses of sweet-clover straw.[3]

                                              |       | Nitrogen-
         |         |       | Fiber   |        | Crude |   free
  Sample.|Moisture.|  Ash. | extract.|Protein.| fiber.| extract.
  -------+---------+-------+---------+--------+-------+-----------
         |         |       |         |        |       |
  No. 1  |  4.2    |  3.18 |  1.20   |  8.31  | 49.37 |  33.74
  No. 2  |  4.7    |  3.40 |  1.03   |  5.88  | 53.65 |  31.34
  No. 3  |  5.34   |  3.02 |   .89   |  6.14  | 51.11 |  32.9
  No. 4  |  5.55   |  4.14 |  1.54   |  8.44  | 43.00 |  37.33
  No. 5  |  4.75   |  2.64 |  1.28   |  6.81  | 51.42 |  32.8
  No. 6  |  4.23   |  2.58 |  1.13   |  5.44  | 55.41 |  31.21
  No. 7  |  5.53   |  3.66 |  1.52   |  7.19  | 46.34 |  35.70
  No. 8  |  4.65   |  2.98 |  1.38   |  7.09  | 51.56 |  32.34
  No. 9. |  4.92   |  4.22 |  1.70   |  8.44  | 46.11 |  34.61
  -------+---------+-------+---------+--------+-------+-----------


[3] These analyses were made by the Bureau of Chemistry.



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Transcriber Note


Minor typos may have been corrected. Illustrations were moved to
prevent splitting of paragraphs. Content produced from files generously
provided by the USDA through The Internet Archive and all resultant
files are placed in the Public Domain.





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