xt7qjq0ssh44 https://exploreuk.uky.edu/dips/xt7qjq0ssh44/data/mets.xml   Kentucky Agricultural Experiment Station. 1930 journals kaes_circulars_218_02 English Lexington : The Service, 1913-1958. Contact the Special Collections Research Center for information regarding rights and use of this collection. Kentucky Agricultural Experiment Station Circular (Kentucky Agricultural Experiment Station) n. 218 text Circular (Kentucky Agricultural Experiment Station) n. 218 1930 2014 true xt7qjq0ssh44 section xt7qjq0ssh44 1 . it
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THOMAS P. COOPER, Dean and Director
age t
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mts. ill-   C April, 1930 U `
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the com 4Published in connection with the agricultural extension work car-
d be ;I*?¥· ned on by cooperation of the College of Agriculture, University of
rilln This Kentucky, with the U. S. Department of Agriculture and distributed
_ * _ ]_ nn furtherance of the work provided for in the Act of Congress of
1l1 drnn. May gy 1914_

 Important Pomts
Sweet clover is one of the most valuable of all legumes for °
pasture and soil improvement on Kentucky farms. Properly man-
aged, sweet clover pastures will support at least one steer or dairy
cow per acre from early spring until late fall, which is two or three
times the capacity of Kentucky pastures at the present time. The
growth of grasses is greatly stimulated by sweet clover when it is
included in pasture mixtures.
A good stand of sweet clover will add from 100 to 250 pounds
of nitrogen per acre to soil if pastured or plowed under. This equals
the amount of nitrogen contained in from 10 to 25 tons of farm .
manure. Even when utilized as a catch crop, it may give almost as
large nitrogen returns.
Most Kentucky soils must be limed in order to grow sweet
clover successfully, but the ability to grow this crop amply justifies
the expense of liming. Two tons per acre of limestone that will pass
, a 10-mesh screen and containing the dust is recommended.
A majority of experienced growers believe late winter or
early spring seeding with scarified seed to be the most reliable
method ot getting a stand. Commercial cultures afford the most
convenient method of inoculation.
Probably the best way of utilizing sweet clover for permanent
pastures, either alone or in mixtures, is to divide the pasture area
into two parts, so that both young and old sweet clover will be avail-
able each year. Mixtures are preferable to sweet clover alone, a
mixture of sweet clover, lespedeza and orchard grass being indicated
as the ·best for Kentucky outside of the Bluegrass Region, where
bluegrass may replace the orchard grass.
The use of sweet clover for hay should be confined to the first-
year crop, altho the second-year crop may be utilized in case of zi
shortage of other hay. Sweet-clover hay should not be fed continu- t
ously unless other kinds of hay are fed with it.
The production of sufficient sweet-clover seed on Kentucky
farms for home use is recommended. Growing seed for market may
be profitable in some cases, but as a rule the crop can be utilized
more profitably in other ways.
’The most economical way of obtaining the benefits of sweet
clover for soil improvement is to utilize the crop for pasture. Great
opportunities of improving soils are afforded thru its use as a catch

 mes for
‘lY n1 .
Oi- euiii Sweet Clover for Kentucky
    By E. J. KINNEY
1en lt is
F pounds
is equals
ngfogligl Perhaps no other crop has gained more rapidly in popularity in
the United States than has sweet clover durm the ast few ears.
g P Y
w sweet In nearly every state in the union the acreage devoted to this crop
  has increased in a striking way, and in many sections it is fast be-
coming one of the most extensively grown legumes. Interest in sweet
MGF OT clover first develo ed when its remarkable value for soil im rove-
reliable P P
le mm ment, especially for depleted soils, was recognized. Its ability to
make a vi orous and even rank rowth on badl worn land, rac-
_ g S Y P
Fgagfgg tically devoid of organic matter, is not approached by any other
1e avail. legume. The rapid progress that the crop has made in recent years,
igggieg however, has been due largely to the discovery that, in addition to
, where its value for soil improvement, it is one of the most productive, if
f_ L ‘ not the most productive, of pasture crops. The forage produced is
1- - . .
E; Gifs, just as palatable to stock, when once accustomed to rt, as that of
lontinu- other standard pasture plants, and just as nutritious. Sweet clover
lumcky is extremely drouth resistant, a characteristic which makes it par-
er may ticularl de endable for summer asture. In man warts of the
__ Y P P Y l
ummed Corn Belt and in the northwestern wheat- rowin areas sweet clov-
g S
; Sweet ef has taken a front rank as a pasture crop. Sweet clover produces
. Grp? an abundant crop of seed under all ordinary climatic conditions.
e . . . . . .
ma This makes the seed relatively cheap, an important factor in 1n-
creasing tl1e use of any forage crop.
Undoubtedly, sweet clover can be of very great help in putting
the agriculture of Kentucky on a more profitable basis. It seems
certain that any marked increase in farm income in the State can
bf? brought about only by developing the livestock industry, partic-

 4 Km/ztrzlrcky Extension Circular N0. 218
ularly dairying and sheep raising. This cannot be done, however, loti
without an increase in the carrying capacity of pastures and a of:
greater production of other feed crops. Even un-der the most favor- a fi
able soil conditions, the carrying capacity of pure grass pastures is im;
not large. On worn lands or on soils of only moderate fertility, blo
grass pastures are very unproductive. By substituting sweet clover dis
for the grasses or by including it in pasture mixtures, the produc- sm
tivity of Kentucky pastures can easilybe doubled. In addition, the tstei
use of sweet clover will make it possible to add to the pasture area sor
lands so badly worn that they have been practically abandoned. It prt
is not only its pasturage value that makes sweet clover of such po- var
tential importance to Kentucky. Its use is certain to result in a rapid era
and substantial increase in soil productivity, thus insuring better cas
yields of all kinds of crops._ _   r ne‘
` Most Kentucky soils must be limed in orderito grow sweet clover fm
successfully. It is_ safe to say, however, that no investment that the att
Kentucky farmer can make will pay larger returns for the money pk
invested than that spent an liminghis land. Liming is necessary for ty]
the production of alfalfa and red clover as well as sweet clover. Sw
I Lime greatly increases the yield of annual legumes also, the most ml
= important ofiwhichare soybeans, cowpeas and lespedeza. Limestone du
is so widely distributed in Kentucky that no region is far from a im
source of supply. Marl, a good substitute, is present in many local- m
I ities. Probably ia no other state can land be limed at a lower cost. Ii;
\~Vhere soils are -deficient in phosphorus, as are practically all va
Kentucky soils outside of the Bluegrass area, the best crop yields se
cannot be obtained without the use of phosphatic fertilizers. In sow- tu
l ing sweet clover on badly worn land, it is especially necessary to use
a carrier of phosphorus to insure satisfactory results. . The liberal
use of phosphate fertilizers on pasture lands where the soil lacks
phosphorus is a real economy. It benefits the pastures and most 0f
the phosphorus is returned to the land for the use of other crops. M
Sweet clover is the popular name used in this country for mem- sl
bers of a group or genus of legumes known botanically as Meli- y

 Sweet Clover for Kentucky 5
, lotus. In some sections this group name, Melilotus, is used instead
1 of sweet clover. Sweet clover is native to Europe and Asia and only
- a few types have been introduced into America. By far the most
s important of these is whitesweet clover (Melilotus alba). Yellow
, blossom sweet clover Qlllelilotus officinalis) is also quite widely
r distributed andin some cases is preferred to the white. Yellow .
- sweet clover does notgrow so large as the white and produces finer
2 stems, making it more desirable for hayproduction. It also matures
1 somewhat earlier. Bothithe white and yellow are biennials. Seed is
t produced the second year, after which the plants die. An annual
- variety of white sweet clover known as Hubam was discovered sev-
l eral years ago, but it has apparently not proved so valuable in most
r cases as the common biennial type. The possibility of discovering
new varieties of sweet clover better adapted for certain purposes or
F for certain conditions than the common types is now attracting the
3 attention of investigators. In,almost any field of sweet clover,
Q plants may begfoundgthat are distinctly different from the average
r type. Already,se`v‘ei*al varieties of merit have been developed from  
, such plants,,amongi   thetearly-flowering Grundy County,} a ,
é rather dwarfhtype with fine stemsaespecially adapted for hay pro-_ T
L_ duction. Atype has recently been found in Canada that has many V
; more and finer stems thanfthe commonsorts and resembles alfalfa
_ in appearance. Undoubtedly many more valuable varieties will be
, found. A number of new types' from Europe and Asia·are under
i test in this country and it'is hoped that some of these may_prove of T
I value. A later—maturing variety giving a longer pasture period the
5 second year of_its growth would bei especially desirable for Ken-
· tucky. A _ A _ V _ '
E Sweet clover ripens its seed crop during August under normal
. conditions, but early clipping or pasturing may cause latermaturity.
The seeds are enclosed in a hull and quickly shatter from the plants
* after ripening. Very few, if_any, germinate until the following
· spring even under the most favorable moisture conditions. The
· young plantsappear during March or early April and, after becom-

 6 .Kentu,cky Extension Circular N0. 218
ing well rooted, grow rapidly, reaching a height of three to four- be C
feet and branching quite freely. During the first season a bud than
crown is formed, carrying the buds which produce the new shoots the
the following spring. The crown does not persist, however, and but sion
one set of buds is formed. Both the first and second year any re- Shot
newed growth following grazing or cutting the plants must, there- and
fore, come from buds on the stem and not from a crown. In this it mm
is distinctly different from red clover or alfalfa, which have a per-
sistent crown giving rise to new shoots during the life of the plants. T
Where financial conditions permit and limestone can be obtained  
without great difficulty, it is most practical to use fairly large gms
amounts, one and a half to two tons an acre, for the initial treat- my
ment. This will insure favorable conditions for sweet clover or
other limegloving plants for 6 to 8 years or longer, on practically
all soils. There is no doubt, however, that good results may be se-
cured with much smaller applications. Even as little as 500 pounds S
per acre of fine limestone or burned lime may permit raising one but
- or two fair crops of sweet clover ont some soils, but it is scarcely The
, advisable to use less than 800 to 1,000 pounds. When a ton or more Hgh
per acre is used, limestone ground to pass a 10-mesh screen (100 Wha
openings per square inch) is sufficiently fine, but for lighter appli- Th€
cations much finer grinding is necessary. All the material should wat
pass a 40—mesh screen, or in case of very small applications a 100- til 3
mesh screen. In using small amounts of limestone, it is necessary mall
that it be spread very evenly. The best results are obtained by using gm
a grain drill with fertilizer attachment. It may be necessary to go A U
i over the field twice in order to sow the desired amount. If th€ $“‘€
sweet clover is to be sown on fall—sown grains, the limestone may SCM
be druied in with the grain. ciall
Burned lime is about twice as effective, pound for pound, 35 .  
ground limestone, and where Finely ground burned lime can be Ob- uns,
tained, as is possible in some places in Kentucky, it is especially l by;
suitable for small quantity applications because less need be used mm
than of ground limestone. Slaked lime (hydrated lime), which may lab,

 I Sweet Clover for Kentucky 7
V be obtained almost any place in paper bags, is also more effective
l than ground limestone, 3 pounds being equivalent to 4 pounds of
l the latter in neutralizing soil acidity. For a more complete discus-
t sion of the use of limestone, Kentucky Extension Circular No. S9
' should be obtained. A list of manufacturers of ground limestone
' and other forms of lime can be secured from the Kentucky Experi-
t ment Station.
_ The soils of Kentucky, as a rule, are not strongly acid, and in
some cases fair crops of sweet clover can be grown without lime.
This is most likely to be true on rather fertile soils well supplied
with organic matter. The best way to determine a soil’s ability to
l grow sweet clover is to include a pound or two of seed when sowing
’ grass or other forage crops. Thoro inoculation is especially neces-
' sary on unlimed land.
, Seed and Seeding. Both the unhulled and hulled seed are used,
y but in recent years most of the seed on the market has been hulled.
I The hulled seed usually is of better quality because in hulling the
» light, immature seeds are removed. The hulled seed is also some-
· what easier to sow. In nearly all lots of sweet clover seed some of
the seeds—frequently a large percentage—have such hard seed
coats that they cannot absorb water and germinate, at least not un-
til after long exposure to moisture. In tests it has been found that
many of these hard seeds require at least a year in the ground to
germinate. If the seed coats are scratched, germination is prompt.
A machine known as a scarifier has been devised for scratching
sweet clover seed and a large proportion of the seed crop is now
scariiied. The use of scariiied seed is generally recommended, espe-
cially for late winter an-d spring seeding. For fall or winter seeding,
which is preferred by some growers, the unscarified seed should be
’ used. There is always considerable risk connected with the use of
unscariiied seed, as it is practically impossible to determine its value
l by germination tests. New seed which may give excellent germina-
tion under field conditions may give very low germination in the
laboratory, especially if the tests are made in the fall or early win-
\ )

 V8 Kentucky Extension Circular N0. 218
ter. There are equal chances, however, that a small percentage will The
germinate in the field. F befo
` i  r· . .4 · . . 5¤YY·
Usually sweet clover is sown inalate winter or early spring, {O1- Stub]
lowing themethods practist with red clover; If natural ageneieg— by “
freezing, thawing and rainseare depended upon to cover the seed,
january or early February seeding is advisable. Sowing on a so- Sl
called "honeycomb" frozen surface gives the best assurance of good advii
covering; lfossibly somewhat more reliable results can be secured T-
·with`eit;her rerlicloveriorisweet clover by sowing with a clover seed is SO
drilliaseifrlyiasi‘possiblefii‘1 the spring. A grain drill with clover hun,
seeding-iattachni`eiit*rhayialso be used or the field may be harrowed {mn
with a 'spi'l€e—toothfof>1·otary harrow after broadcasting the seed, mix,
Little of theseedis covered directly by these operations, but rains smc
wash the loosened soil over the seeds, covering them very satisfac-
torily. This method of seeding is somewhat expensive and occasion- Il
ally unfavorable weather prevents seeding as early as is desirable. with
. not
· Fall andrearly winter seeding of sweet clover is practist bysome whe
_ -gram-;rg,i‘ apparehtlyiiwithgood results. Unhulled or unscarified mm
seed may be sownlas early as 'October, or even earlier if new seed Cost
` is used, with little danger of fall germination. Thus it is possible tho;
to sow with fall grains. Tests at the Virginia Station, however, gave my
fewer plantsfrom both fall and early winter seeding and a smaller {quit
yield of forage than from late winter and early spring seeding. In uw
sowing in old pastures, meadows, or untilled land, early winter `vitl
seeding might be advantageous, as it would give an opportunity for a bl
the_seeds to work down thru‘the‘vegetati‘on. As stated, however, wil
‘ there is considerablerisklin sowing unscarified seed, and in the lah- Stir
runes; Kei1tucl ¤ ’»... . Sweet
Sweet clover hay has generally been regarded as a wholesome W bemil
roughagefalitho occasionalcasesj of-eattlefpqieenjng have Occumid g UQG ll
` from feeding it. ""f1i_"a ¥b}’VTll’1StZl1'1C(:‘;§'_tji'1€ [losses have. been. rather , Wlthf
- heavy. Until recently   wasbelieved thatinjury was caused only by 1 mgm
mouldy or spoiled hay. paying theepast year or so, however, a de- Chim
cided increase in the number of“cases` of poisoning has been"report— the Y
ed, espec_ially from sections where sweet clover hay is used extens- lime
ively. While someinvestigators still believe that only spoiled hay is if all
dangerous, others believe that any sweet clover hay will cause pois- ham
oning ififed continuously in large amounts. There seems to be good $121yS*
. evidence to support the latter view] In animals affected, the blood mg l
loses its lclottingpower, resulting in internal bleeding. Apparently, fam
there is little, if any,Vdanger from this disease if other kinds of llily thou
are used along with the sweet clover hay or if it is not used as the pam
_sole roughage for long periods. _ SC
Seed Prodnclionj Sweet clover seeds freely, yields of 8 to IO blk bmi
of seed per acre? not- being uncommon. The seeds shatter very r€é1d·   for l
ily, however, and great care is necessary in handling the crop to pf€· i /5_ tl
vent losing a large proportion of theseedf At one time considerabl€ SOIL

 Sweet Clover for Kentucky l3
E seed was produced in North Central Kentucky, the harvesting and
j threshing being done entirely by hand. In recent years the price of
n seed has been too low to  ustify such expensive methods of produc-
j tion and but very little is now harvested in this region. A large part
E of the seed crop is now grown in the western and northwestern
V parts of the country, altho considerable is produced in certain sec-
tions of the northern Corn Belt. The crop is cut with grain binders
fitted with pans to catch the shattered seed, or with self-rake reap-
8 ers. The seed i_s threshed with an ordinary grain separator, a clover
‘ liuller or is fiailed out by hand. The combined harvester now com-
ing into use so extensively in the wheat—growing regions of the
_ West and Northwest is said to handle sweet clover very economi-
5 cally and with little loss of seed. Probably this will result in con-
, - fining the commercial production of seed in the future to those
  areas where these machines are used.
‘ There has been little tendency among Kentucky farmers to save
°‘2· i ·’ sweet clover seed and doubtless the crop can generally be used to °
S A 'i`‘ better advantage in other ways in this State.iSaving seed for home
j g use is always a desirable practice, however, where it can be done
I without hiring extra help. Small crops can be harvested with the
Y   mower, but to prevent shattering it is necessary to follow the ma-
_ ‘ chine and fork the swath aside so that the team will not run over
_ the plants on the next round. The self—rake reaper or hemp har-
_ vester, which is a special type of self-rake reaper, should be used
S if available, as these machines are far superior to the mower for
_ harvesting the seed crop. After drying in small shocks for a few
1 days, the seed can be beaten off the plants very easily. After thresh-
1 ing, the seed should be put thru a coarse screen and cleaned on the
ly fanningi mill. Those interested in commercial seed production
J should send for Farmers’ Bulletin 836 of the United States De- ,
3 partment of Agriculture.
Soil 1'mpr0veMlz.ent. By far the most practical way of realizing
_ benefits from sweet clover for soil improvement is to use it
. l for pasture. The income from the crop is thus secured and from
. ` 75 to 85 percent of the plant food in the crop is returned to the
2 soil. Where little stock is kept, it is much more difficult to utilize

 14 Kentucky Extension Circular N 0. 218
legumes economically for soil improvement. At least part of the clover
legumes grown must be plowed under in order to maintain an ade- mm 6
quate supply of soil nitrogen to meet the requirements of other Year Y
crops. To devote an entire season to growing a crop to plow under would
is an expensive practis, but this may not often be necessary if full Plomcl
advantage is taken of opportunities of growing legume catch crops quired
in the intervals between regular crops. As a matter of fact, recent use IQ
studies at the Illinois Experiment Station and at the Ohio State have ll
University have shown that surprisingly large quantities of nitro- API.
gen can be added to the soil by growing catch crops of sweet clover, Wm M
The Illinois Station determined the amount of nitrogen in sweet the {ir
clover at various stages of growth on nine experiment fields in the be the
state. It was found that, on an average, crops sown in the spring athicl
showed an accumulation in tops and roots of around 250 pounds of tim, O1
nitrogen per acre by May 1 of the following year. This is as much sary H
as is contained in 25 tons of average farm manure or over 1,600 SONS,
pounds of nitrate of soda. This seems almost incredible and prob- {mm.
ably such results could not be expected except under extremely Some,
favorable soil and climatic conditions. VVillard, however, reports mab],
. that as a result of four years’ experiments on upland soils at Ohio to add
State University the least amount of nitrogen found in the crop on Soir ti
May l of the second year was 120 pounds per acre. He also found tation
that sweet clover at this date contained four-fifths as much nitro-
gen as at any subsequent stage of growth. This means that sweet Thc
clover sown in small grains in the spring and plowed un-der the fall bl
following spring in time to plant the land to corn adds almost as withoi
much nitrogen to the soil as if it were left to make its maximum GOP- l
growth. These discoveries are of great significance and tend to es- Yomlii
` tablish sweet clover as the most remarkable crop in existence from Afom
the standpoint of possible value for soil improvement. It is scarcely and 3*
necessary to point out the wonderful opportunities presented for ooo il
increasing crop yields if the results obtained in Ohio and Illinois about
can be duplicated under average farm conditions. Nitrogen is the ollfog
limiting factor in crop production in Kentucky and the problem of mo
maintaining an adequate amount; in the soil economically has alw&y$  I br no
been a difficult one to solve. If 100 pounds or more of nitrogen per `
acre can be added to the soil by growing a catch crop of sweet

 Sweet Clover for Kentucky 15
clover, the solution of the problem seems to be at hand. Such a re-
turn every two years in a rotation of corn and wheat or any tw