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EFFECT OF CLIPPING ON THE
SL’BSEQUENT SEED
YIELD OF SEVERAL CLOVERS

Thesis {orthe Degree of M. S.
MICHIGAN STATE COLLEGE
Maurice C. Frakes

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EFFECT OF OLIPPING ON THE SUBSEQUENT SEED
YIELD OF SEVERAL CLOVERB

&
by -, 5;“
r?”
Maurice G. Frakee

 

A THESIS
submitted to the Graduate School of Michigan
State College of Agriculture and Applied
Seience in partial fulfilment of the
requirements for the degree of

MASTER or sermon
Department of Farm Crops

1940

THES‘S

ACKNOWLEDGEMENT

The author “fishes to express his
sincere appreciation to Professor
0. R. Megee for helpful advice and
guidance throughout this problem

and final review of this paper.

37484

EFFECT OF GLIPPING ON THE SUBSEQUENT
SEED YIELD OI" SEVERAL CLOVERS

INTRODUCTION

One of the principle problems confronting the farmers
of Michigan in the production of sweet clover (Melilotus
§g2§_Desr.), medium red or June clover (Trifolium pratense L.),
mammoth red clover (Trifolium pratense perenne Hort.) and
alsike clover (Trifolium.hybridum L.) seed consists in hand—
ling the early spring growth in such a manner that a maximum
yield of seed is obtained and seed harvest is facilitated.

It is a general practice among Michigan seed growers
to take the first crop of mammoth red clover and alsike
clover, the second crop of medium red or June clover and
either the first or second cr0p of sweet clover for seed pro-
duction. However, in order to eliminate bulky growth, reduce
the amount of coarse material to be handled at seed harvest,
control weeds and insects, obtain a hay crop, increase seed
yields or cause the crop to set seed at a more favorable time
farmers have resorted to rolling, clipping or pasturing the
first crop. As these clovers differ widely in their reaction,
desirable treatments for one clover is not necessarily the
best treatment for any one of the other clovers. Neither can
results obtained in other states he applied to Michigan cone
ditions owing to variations in soil type and climatic condi-
tions. '

This thesis reports specifically on the effect of cutting

the early spring growth of the above mentioned clovers on seed

yields. Since each clover reacts differently to cutting
treatments they are discussed separately and the literature

reviewed separately.

SWEET CLOVER (Melilotus aIba Deer.)

Sweet clover differs from other clovers in that when
it is grown on fertile soil it makes a more rank growth
attaining a.height of six to seven feet. With such a rank
and coarse growth of sweet clover it is very difficult to
harvest the seed crop efficiently with a binder, mower or
combine. The bulky unharvested crop is difficult to plow
under and makes very poor material to add to the soil as
organic matter. As a result many farmers burn over the
field thus losing a hay or pasture crop, a seed crop and
most of the organic material. Some growers cut or pasture
the early growth of sweet clover to reduce the bulky growth
and report a loss of stand and a corresponding decrease in
seed yields.

Coe (1) found that only those portions of the plant ex—
posed directly to the sunlight set seed abundantly and that
thin stands usually produced more seed than heavy stands due
to seed setting on the lower branches. He found that on a
heavy stand, seed set only on the upper 24 to 30 inches of
the plant. If the stand was thick and indicated a yield of
from one to three tons of dry matter per acre he recommended
pasturing or cutting for hay previous to the production of a

seed crop. Coe found that the second crop will ordinarily

3.
produce more seed if there is a heavy stand to begin with.
Willoughby and Wells (12) working in.Kansas, recommended
pasturing the first "two or three months" of growth or clip-
ping the early growth of the season when 12 to 16 inches in
height leaving a stubble of 10 to 12 inches. Gerber, et a1,
(2) working in West Virginia found that sweet clover cut at
the 'prebud' stage of growth (26 inches in height) could be
depended on to produce “ample seed for reestablishing the
crop", whereas if the sweet clover was cut at a later stage
it may or may not produce sufficient seed, depending somewhat
on the season. Willard (10) working in Ohio, clipped sweet
clover with a hand sickle to imitate the action of a “stripped.
binder and found that clipping usually decreased the yield of
seed. Later cuttings gave correspondingly greater decreases
in seed yield. He clipped the clover six to ten inches below
the general level of growth at the time of clipping. Willard
found that clipping sweet clover as early as May 9, with the
mowing machine cutter bar set as high as possible resulted in
nearly total loss of stand.

An experiment was set up on the College farm at East
Lansing, Michigan, during the season of 1939, to determine
whether sweet clover could be cut during the second year of
growth and not materially reduce the seed yield. Two series
of sixteen.plats (15 feet by 180 feet) were laid out with
2%—foot alleyways between each plat. All cutting treatments
were made in duplicate. One group of four plats was cut back

to four inches from 6, 9, 12 and 18 inches. Another group

was cut back to seven inches from 9, 12, 18 and 22 inches
and a third group was cut back to ten inches from 12, 18,
22 and 32 inches. Every fifth plat was left as a control
or check and received no treatment. Iron shoes fitted to
a mowing machine cutter bar as described by Megee (4) were
used to obtain the desired height for cutting the sweet
clover. At the time of the first cutting, made May 8, the
sleet clover was six to seven inches high. The last cutting
was made June 1, when the sweet clover was in the early bud
stage of bloom and from 30 to 32 inches in height.

Table I shows the various cutting treatments, the coef-
ficient of yield (8) for each plat of the duplicate series
and the condition of the crop when harvested. The average
yield of eight check plats was 301.34 pounds of clean seed
per acre. Results indicate that although clipping sweet
clover did not, in many cases, increase the seed.yield
materially, neither was the yield decreased. Best results
from the standpoint of seed yield were obtained when the
clover was clipped to four inches from a height of 10 to 18
inches. It is of interest to note that when stubble of four
inches was left the later the clipping was made, up to
May 23, or when the clover was 18 inches in height, the higher
was the yield of seed, This may be due to the fact that the
stand was decreased to 75 or 80 per cent of the check plats.
The thinner stand in combination with profuse branching may
have induced larger yields of seed, When the stand was de-

creased below 75 per cent the seed.yields dropped.

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6.

Clipping off two inches of growth when the plants were
6, 9 and 12 inches high set the sweet clover back some at
the time of cutting but recovery was very rapid and differ-
ences in height, stand and size of stems could not be detect-
ed when compared with unclipped plants at harvest time. This
agrees with the results obtained by Garber, et a1, (2) in that
plants clipped early made a more rapid recovery than those
clipped at a later stage of growth.

When five inches of growth were removed from the plant
(plats 2 and 7) the subsequent growth was not decreased
appreciably although it was somewhat shorter and the stems
were smaller when compared with plants on the check plate at
the time of harvest. The stems were not fine enough however
to increase to any great extent the ease and efficiency with
which the crop could be harvested with a binder, mower or
combine. When eight inches or more of the plant was removed
the resulting crop was much shorter and finer of stem when com-
pared with uncut plants at harvest time. Any one of plats
number 3, 4, 8, 9, l3 and 14 could have been harvested with

ease using any of the common methods of harvesting.

MEDIUM RED or JUNE CLOVER (Trifolium pratense L.)
Although farmers in Michigan have, for many years, re-
moved the first crop of medium red clover leaving the second
crop for seed, all growers are not in agreement as to the
proper time to cut the first crop. Some out as early as the
bud stage of growth while many prefer the full bloom stage

and others leave until the heads are turning brown. The

7.
practice of pasturing the field for various periods in the
spring is sometimes followed. Recommendations for the time
of cutting the first crop varies with the section of the
country. Westgate and Hillman (9) recommend cutting when the
clover is two-thirds in bloom. Moore and Delwiche (7), work-
ing in Wisconsin, cut at 40 to 50 per cent bloom. Hunter (3)
of Oregon, gives a wide range. He recommends cutting from
May 1 to June 20, depending on the season, clipping later in
a wet season than in a dry one. Willard, et a1, (11) working
in Ohio, recommend cutting the second week in June, or about
when the first flowers appear.

An experiment was set up during the seasons of 1938 and
1939, on the College farm at East Lansing, Michigan, to deter-
mine at what stage of growth medium red clover should be out
under Michigan conditions to give the greatest yield of seed.
The experiment consisted of 16 plats 11 feet x 180 feet
(1/22.000 acre). Six cutting dates, replicated twice, were
used with four checks.

Table II shows that early clipping of the first crop of
medium red clover resulted in increased seed yields with the
increase becoming greater as the cutting was delayed up to the
time the clover started to bloom. The greatest increase in
seed production was obtained when the clover was cut in the
late bud stage of growth or just as the clover started to
bloom. This is in agreement with Willard's work in Ohio. A
slight decrease from this peak production of seed was obtained
if the cutting was delayed.until the clover was three-fourths

8.
to full bloom. A very marked decrease in seed production,
lower than the check yields, was obtained if the first crop
of clover was out after the blossoms start turning brown.
Table II. The effect of clipping medium red clover at

various stages of growth on the seed yield.

Lbs. seed per acre Condition of crop when

 

 

 

Treatment 1938 1939 clipped 1939

Not clipped 553 111

Clipped May 23 114 122 10- high

Clipped June 1 162 140 14' high, very early bud stage
Clipped June 8 199 178 18' high, 1/5 bloom

Clipped June 15 176 130 20" high, 1} bloom, 1/10 bloom
Clipped June 23 --- 59 20" high, full bloom, 1} brown
Clipped July 1 --- 22 20' high, % brown

Plats out June 8, 1939, when the clover was beginning to
bloom gave a seed yield.of 178 pounds of plump seed per acre
and no shrivelled seed when harvested August 16. Another plat
treated in the same manner gave a seed yield of but 21.4
pounds per acre of plump seed and 96.0 pounds of shrivelled
seed when harvested on August 7, indicating the necessity of
waiting until the crop is well matured before beginning the
harvest.

A plat cut at weekly intervals on May 23, June 1, June 8
and June 15 was harvested for seed on August 29, giving a
yield of 76 pounds of plump seed per acre, indicating a
possibility of pasturing medium red clover advantageously for
a short period in the spring and leaving the field for seed
production (6). It is possible that better seed yields would

be obtained if the crop was not pastured after June 5, to
allow the plants to recover for a longer period of time.

The first crOp of seed was harvested from the control
plats July 26. A second crop of seed was harvested.October
11, giving an average yield of 18 pounds of plump seed.per
acre. Dry weather during the fall of 1939, made it possible
to make this harvest. It is not recommended, however, that
seed be harvested so late due to difficulties ordinarily
encountered in getting the crop sufficiently dry to thresh at
that time.

Data were taken to determine the effect of clipping on

the relative number and size of seed per head.

Table III. The effect of time of clipping medium red clover
on the average number of heads per square foot,
weight per 1,000 and number per head of plump
seed at time of harvest, 1939.

 

 

 

 

Heads per Plump Seeds

Treatment square foot No. per head Wt. per 1,000

heads seeds grams
Not clipped 75.6 30.0 1.87
Clipped May 23 61.8 44.9 1.55
Clipped June 1 ‘ 58.0 58.0 1.62
Clipped June 8 55.0 60.2 1.53
Clipped June 15 53.8 64.8 1.55
Clipped June 23 40.2 72.4 1.47
Clipped July 1 37.0 77.5 1.43

Table III shows that delayed cutting made fewer heads

per square foot, more seeds per head and smaller seed.

Similar results were obtained in 1938.

10.

MAMMOTH RED CLOVER (Trifolium pratense perenne Hort.)

Mammoth red clover, a single cut clover, makes such a
rank growth when the crop is grown on a fertile soil that
growers have difficulty in handling the seed crop efficiently.
In experiment was set up during the seasons of 1938 and 1939
on the College farm at East Lansing, Michigan, to determine,
if possible, a cutting treatment which would cut down the
amount of bulky growth and still maintain or increase seed
yields. The experiment consisted of 16 plats 11 feet x 177
feet (1/22.373 acre). Six cutting dates, replicated twice,
were used with four checks.

Table IV. The effect of cutting mammoth red clover at
various stages of growth on the seed.yield.

Pounds seed per acre Condition of crop

 

 

Treatment 1938 1939 when clipped 1939

Not clipped 212 230

Clipped.May 23 261 182 7' high

Clipped.June 1 270 71 12' high

Clipped June 8 243 62: 15' high

Clipped.June 15 226 393 19' high, early bud stage
Clipped June 23 -- 16 23' high, late bud stage
Clipped July 1 --— 9 23' high, 1/3 bloom

Table IV indicates that the effect of clipping mammoth
red clover on the subsequent seed.yield.varies with the
season. Clipping greatly reduced the seed yield of the suc—
ceeding crop, even when out in very early stages of growth,
during a dry season. In 1938, a season of greater than aver-
age rainfall, the seed production was not decreased as a

result of clipping. The peak of seed production during that

10.

MAMMOTH RED CLOVER (Trifolium pratense perenne Hort.)

Mammoth red clover, a single cut clover, makes such a
rank growth when the crop is grown on a fertile soil that
growers have difficulty in handling the seed crop efficiently.
An experiment was set up during the seasons of 1938 and 1939
on the College farm at East Lansing, Michigan, to determine,
if possible, a cutting treatment which would cut down the
amount of bulky growth and still maintain or increase seed
yields. The experiment consisted of 16 plats 11 feet x 177
feet (1/22.373 acre). Six cutting dates, replicated twice,
were used with four checks.

Table IV. The effect of cutting mammoth red clover at
various stages of growth on the seed yield.

Pounds seed per acre Condition of crop

 

 

Treatment 1938 1939 when clipped 1939

Not clipped 212 230

Clipped.May 23 261 182 7' high

Clipped June 1 270 71 12' high

Clipped.June 8 243 62: 15' high

Clipped.June 15 226 393 19' high, early bud stage
Clipped June 23 -- 16 23' high, late bud stage
Clipped July 1 -—- 9 23' high, 1/3 bloom

Table IV indicates that the effect of clipping mammoth
red clover on the subsequent seed.yield.varies with the
season. Clipping greatly reduced the seed yield of the suc—
ceeding crop, even when out in very early stages of growth,
during a dry season. In 1938, a season of greater than aver-
age rainfall, the seed production was not decreased as a

result of clipping. The peak of seed production during that

11.
year was obtained from plats clipped early, June 1 or before,
as compared with June 8 for medium red clover. This placed
the desirable cutting date for mammoth red clover about two
weeks before the bud stage of bloom when the plants were 8 to
10 inches tall while the proper time for medium red clover
was early bloom stage with the plants 18 to 20 inches tall.
During the dry season of 1939, the growth of the mammoth red
clover on the control plate was not as extensive as the growth
made in 1938, hence these plats had a tendency to produce more
seed. Due to a deficiency of moisture those plats on which
the plants were clipped failed to make seed yields comparable
to the yields obtained during the more favorable season of the
year before. Willard, et a1, (11) working in Ohio, found that
it was unsafe to clip mammoth red clover for seed after May 20,
and that it probably reduced the seed yield whenever it was
done.

Plats Clipped.June 15, and harvested September 14, gave a
yield of 39 pounds of clean seed per acre while a plat cut at
weekly intervals (May 23, June 1, June 8 and June 15) and har-
vested September 14, gave a yield of 22 pounds per acre. This
indicates that pasturing mammoth red clover to a certain date
may be more detrimental to seed production than clipping at
that date. If the clover is pastured the cattle should be removed
from the field a week or 10 days prior to the time the plat
would ordinarily be clipped if the field was not pastured (6).

Data were taken to determine the effect of clipping on the

relative number and size of seed per head.

12.

Table V. The effect of time of clipping mammoth red clover
on the average number of heads per square foot,
weight per 1,000 and number per head of plump seed
at the time of harvest, 1939.

 

 

 

Heads per Plump Seeds

Treatment gguare foot No. per head W1, per 1,000

‘heads seeds grams
Wot clipped 149.0 39.7 1.75.
Clipped.May 23 98.2 47.0 1.62
Clipped June 1 36.0 64.0 1.51
Clipped June 8 29.8 61.8 1.48
Clipped June 15 22.0 64.2 1.43
Clipped June 23 9.6 68.3‘ 1.50
Clipped July 1 6.2 61.1 1.50

Table V shows that delayed clipping greatly reduced the
number of heads per square foot, increased somewhat the number
of plump seeds per head and decreased the size of the seed.
Unlike the medium red clover, delayed clipping after June 1,
had little effect on the number or size of plump seeds per

head in relation to the number of heads per square foot.

ALSTKE CLOVER (Trifolium hybridum L.)

Alsike clover grown for seed often becomes badly infested
with weeds owing to the less extensive growth as compared to
medium red, mammoth red or sweet clover. Fields are sometimes
clipped to control weed growth when the crop is to be used for
seed production. An experiment was set up during the seasons
of 1938 and 1939, on the College farm at East Lansing, Michigan,
to determine to what extent seed yields were decreased by clip-
ping the first crop at various stages of growth. The experiment
consisted of 16 plats 11 feet x 121 feet (l/32.727 acre). Six

l3.

cutting dates, replicated twice, were used with four checks.
Table VI shows that clipping at any time after the

alsike clover is six to eight inches high greatly decreased
the seed yield. When clipped as late as the bud stage of
bloom no seed was obtained, while clipping when the plants
were six to eight inches in height decreased seed yields as
much as 60 per cent. These results agree with those obtained
by Willard, et al, (11) working in Ohio.

Table VI. The effect of cutting alsike clover at various
stages of growth on the seed yields.

Pounds seed per acre Condition of crop when

 

 

Treatment 1938 1939 clipped, 1939

Not clipped 159 259

Clipped May 23 79 36 7' high

Clipped June 1 no seed 2 11' high, early bud stage
Clipped June 8 no seed no seed 13' high, 5 bloom
Clipped June 15 no seed no seed 17' high, full bloom
Clipped June 23 -- no seed 19' high, brown

Clipped July 1 -4- no seed 19' high, brown

During the season of 1938, there was a heavy growth of
weeds on the alsike clover plats. Although clipping May 23
decreased the seed yield considerably it also very greatly
decreased the amount of weed seeds in the clover at harvest.
Clippings made earlier than May 23 may aid materially in check-
ing weeds on badly infested fields and not materially decrease
the seed.yield of the alsike clover.

Table VII. Monthly mean temperatures in degrees
Fahrenheit for 1938 and 1939, as
compared with normal mean temperatures
over a 50—year period.

1938 1939 Normal
Jan. 22.4 26.8 22.4
Feb. 29.5 24.8 22.9
Mar. 40.6 32.0 32.2
Apr. 47.2 43.0 45.6
May 57.2 60.3 56.9
June 65.2 68.1 66.4
July 71.2 71.2 70.9
Aug. 7202 70.0 6805
Sept. 59.6 63.6 61.4
Oct. 53.6 50.9 50.3
Nov. 41.2 37.4 37.5
Dec. 28.2 31.8 27.2

' Data from United States Weather Bureau

14.

METEROLOGICAL DATA'

East Lansing, Michigan.

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17.
DISCUSSION

There were greater fluctuations in seed yields during 1938
than 1939. Excessive precipitation during February and.March
(Chart II) in connection with above normal temperatures during
March and April, 1938 (Chart I, Table VII) stimulated vegetat—
ive growth. It is commonly believed that immoderate vegetative
growth is not conducive to high seed yields. This may in part
account for the lower seed.yield from the plate which were not
clipped and for the correspondingly greater increase in seed
yield from the plats clipped during the season of 1938 than
from those clipped during 1939. Temperatures in.July, August
and September, 1939, were above normal. This in connection
with below regular rainfall for this period produced almost
drought conditions.

In years of normal rainfall the seed of sweet clover does
not ripen uniformly and some difficulty has been encountered in
the use of a combine in that green material goes in with the
seed which causes heating with a resulting discoloration and
decrease in germination of the seed. Owing to exceedingly dry
weather during July and August, 1939, seed which was set on the
sweet clover plants when they were harvested was mature with no
blooms appearing on the upper portion of the plant. Due to the
uniform ripening of seed, all plate with plants small enough to
facilitate harvesting could have been harvested.successfully
with a combine harvester and thresher. A small amount of pre-
cipitation from August 15 to 20, caused some new growth to appear,
flower buds to form and'blooming to take place. These blooms

18.
failed to set seed before frost. It is probable that during a
season of normal rainfall more profuse branching would take
place from the growth buds after the sweet clover had been
clipped.

Sweet clover differs from other clovers discussed in this
paper in its growth habit in that growth starts in the spring
from crown.buds which send up shoots and any later growth made
after the crop is out must come from growth buds in the exile
of the branches and leaves. Cuttings made on sweet clover must
be made at a height that will allow some active growth buds to
remain on the stubble if the plant is to live and make further
growth. If the stand is thick or the plants have started to
bloom, they must be cut at a height of 10 to 12 inches in order
to leave active buds on the stubble for a second crop. If out
before bloom, a height of eight inches is sufficient (5).

In this report, sweet clover clipped when the plants were
12 to 18, 18 to 22, and 22 to 32 inches in height leaving a
stubble of 4, 7 and 10 inches respectively, resulted in a crop
which was much shorter and finer of stems and which maintained
or increased seed yields as compared with plants which were not
clipped.

Medium red or June clover is commonly known as a 'double-cut'
red clover, i.e., two crops may be taken in one season as a crop
of hay and a crop of seed or pasture. Highest seed yields were
Obtained from plate which were out June 8, when the medium red

clover was 18 to 20 inches in height and beginning to bloom.

19.

Mammoth red clover is a single-cut clover, i.e.,
but one crop of seed or hay can ordinarily be harvested
(in one season. Mammoth red clover does not have the ability
to initiate as extensive a new growth when out as does med-
ium red clover, unless it is cut in very early stages of

growth.

Clipping mammoth red clover greatly reduces the seed
yield of the succeeding crop during a dry season, even

when out in very early stages of growth.

Results from clipping indicate that if the first cut-
ting of either medium red or mammoth red clover was pastured
the cattle should be removed from the field a week or ten
days prior to the time the plat would ordinarily be clipped
if the field was not pastured.

Alsike clover is very similar to mammoth red clover in
growth habit in that it is strictly a single—cut clover.
Clipping alsike clover at any time after it reached a
height of six to eight inches reduced the seed yield of the
succeeding crop as much as 80 per cent as compared with the

plats on which the plants were not clipped.

SUMMARY
Experiments were set up on the College farm at East
Lansing, Michigan, during the seasons of 1938 and 1939, to
determine the effect of cutting on the subsequent seed yield

of biennial white sweet clover (Melilotus alba Desr.), medium

20.
red or June clover (Trifolium pratense L.), mammoth red
clover (Trifolium pratense perenne Hort.) and alsike clover
(Trifolium.hybridum L.)

The sweet clover that was not clipped made such a rank
and coarse growth that it would have been most difficult to
harvest a seed crop by the usual methods of harvesting.

Clipping off two inches of growth when the plants were
6, 9, and 12 inches high delayed growth to some extent, but
recovery was very rapid and differences in height, stand and
size of stems could not be detected at harvest time when com-
pared with plants not clipped. Seed yields from these plats
were maintained or very slightly decreased but the growth was
too rank to harvest efficiently for seed.

When five inches of growth were removed from plants 9
and 12 inches high, the subsequent growth was somewhat shorter
and the stems smaller when compared with plants not clipped.
The growth was not fine enough, however, to increase to any
great extent the ease and efficiency with which the crop could
be harvested. Seed yields from these plats were maintained.

Sweet clover clipped when the plants were 12 to 18, 18 to
22, and 22 to 32 inches in height leaving a stubble of 4, 7 and
10 inches respectively, resulted in,a growth which was much
shorter and had finer stems as compared to plants which were
not clipped. This greatly facilitated seed harvest. Seed
yields from these plate were maintained or increased.

Highest yields of medium red or June clover seed were

obtained from plats on which the plants were out June 8, when

 

 

 

21.
the clover was 18 to 20 inches in height and beginning to
bloom. A slight decrease from this peak production of seed
was obtained if the cutting was delayed until the clover was
_ three-fourths to full bloom. A very marked decrease in seed
production was obtained if the first crop of clover was cut
after the blossoms started to turn brown.

Clipping the first crop of medium red clover resulted
in fewer heads per square foot, more seeds per head and
smaller seeds in the succeeding crop as the date of cutting
was delayed.

The seed yield of mammoth red clover during a dry
season was greatly reduced when the clover was clipped, even
when out in very early stages of growth.

Clipping mammoth red clover as late as the early bud
stage of growth during a season of greater than average rain-
fall did not reduce the seed yield as shown by this study.

Results from clipping indicate that if the first cutting
of either medium or mammoth red clover was pastured the
cattle should be removed from the field a week or ten days
prior to the time the plat would ordinarily be clipped if the
field was not pastured.

Clipping alsike clover at any time after it reached a
height of six to eight inches reduced the seed yield of the
succeeding crop as much as 80 per cent as compared with the

plats on whbh.the plants were not clipped.

10.

11.

12.

Coe, H. S.

22.

BIBLIOGRAPHY

Sweet Clover - Harvesting and Thrashing
the Seed Crop.
U. S. D. A. Farmer's Bul. 836. 1917.

Carber, R. J., Hoover, M. M. and Bennett, L. 8.

Hunter, Byron

Megee, C. R.

 

The Effect Upon Yield of Cutting Sweet
Clover (Melilotus alba).
Jour. Amer. Soc. Agron. 26:974-977. 1934.

 

Clover Seed.Production in Willamette
Valley, Oregon.
U. S. D. A. Bur. Plant Ind. Cir. 28. 1909.

Sweet Clover
Mich. Agri. Exp. Sta. Spec. Bul. 152. 1929.

Sweet Clover
Mich. Agr. Ext. Bul. 202. 1939.

McClymonds, A. E. and Hulbert, H. W.

Growing Clover Seed in Idaho.
Idaho Agri. Exp. Sta. Bul. 148. 1927.

Moore, R. A. and Delwiche, E. F.

Spragg, Frank A.

Growing Clover for Seed and Forage in
Northern Wisconsin.
Wis. Agri. Exp. Sta. Bul. 183. 1909.

The Coefficient of Yield.
Jour. Amer. Soc. Agron. 12: 168-174. 1920.

Westgate, J. M. and Hillman, F. H.

Willard, C. J.

 

Red Clover
U. S. D. A. Farmer's Bul. 455. 1915.

Clipping Sweet Clover Intended for Seed.
Ohio Agri. Exp. Sta. Bul. 446. 1930.

Cutler, J. S. and.McLaughlin, J. R.

The Time of Cutting the True Clovers.
Ohio Agri. Exp. Sta. Bi-monthly Bul. Vol.
19, No. 167, p. 39-43. Mar.-Apr. 1934.

Willoughby, L. E. and Wells, E. B.

Sweet Clover in.Kansas.
Kan. Agri. Exp. Sta. Bul. 45. 1924.

 

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