,transcribers ,note ,text emphasis denoted as ,italics4 ,,sweet ,,clover3 ,,growing ,,the ,,crop ,h4 ,s4 ,,coe ,assistant1 ,office of ,forage ,crop ,investigations ,illustration ,,farmers' ,,bulletin #gig ,,united ,,states ,,department ,,of ,,agriculture ,contribution from the ,bureau of ,plant ,industry ,,wm4 ,a4 ,,taylor1 chief ,washington1 ,d4 ,c4 ,april1 #aiag ,,the cultivation of sweet clover should be preceded by a through knowledge of the requirements for obtaining a stand4 ,the white species comprises a very large percentage of the present acreage of sweet clover4 ,annual yellow sweet clover should be sown in no portion of the ,united ,states except the ,south and ,southwest1 and then only as a cover of green-manure crop4 ,sweet clover is being cultivated in practically every ,state in the ,union4 ,at the present time the largest acreage is found in ,the western ,north-,central ,states and in the ,mountain ,states4 ,sweet clover is adapted to a wider range of climatic conditions than any of the true clovers1 and possibly alfalfa4 ,sweet clover will grow on practically all soil types to be found in this country1 provided the soil is not acid and is well inoculated4 ,sweet clover is more drought resistant than alfalfa or red clover4 ,it is quite resistant to alkali4 ,the lime requirement of sweet clover is as high as that of red clover or alfalfa4 ,maximum growth is obtained only on soils that are not acid4 ,sweet clover usually will respond to applications of fertilizers and manure4 ,in the move humid sections of the country good stands usually are obtained by seeding with a nurse crop4 ,only seed which germinates #ge per cent or more should be sown in the spring of the year unless the rate of seeding is increased to make up for poor germination4 ,sweet clover does best when seeded on a well-firmed seed bed which has only sufficient loose soil on the surface to cover the seed4 ,it is very essential that inoculation be provided in some form if success is to be expected4 ,the large number of failures in obtaining a stand of sweet clover are due primarily to acid soils1 lack of inoculation1 and seed which germinates poorly4 ,spring seedings in general are satisfactory1 but in the ,south excellent stands are obtained from midwinter seedings also ,fall seedings are usually successful south of the latitude of southern ,ohio4 ,a ,farmers' ,bulletin 7,no4 #hbj7 on the utilization of sweet clover for pasture1 hay1 and as a green-manure is about to be issued4 ,,sweet ,,clover3 ,,growing ,,the ,,crop4 ,,contents4 ,page4 ,introduction #c ,species of sweet clover #d ,white sweet clover #e ,biennial yellow sweet clover #h ,annual yellow sweet clover #i ,other species of sweet clover #i ,history #aj ,distribution #aj ,climatic adaptations #ab ,requirements for obtaining a stand #ab ,soils suitable for sweet clover #ac ,resistance to alkali #ac ,need of lime on acid soils #ad ,fertilizers #ag ,use of a nurse crop #ah ,choice of seed #ai ,preparation of the seed bed #ba ,seeding #bb ,hulled sweet-clover seed #bc ,unhulled sweet-clover seed #bd ,rate of seeding #be ,methods of seeding #be ,inoculation #bg ,the soil-transfer method #bh ,the pure-culture method #bi ,treatment of the stand #cj ,treatment the first season #cj ,treatment the second season #cb ,sweet clover in mixtures #cb ,eradication of sweet clover #cc ,,introduction4 ,sweet clover is an important forage crop in many regions4 ,although one of the oldest of known plants1 not until very recently has it been considered seriously as a forage plant in this country4 ,the principal causes for not utilizing this crop were its aggressiveness on uncultivated land in many localities1 the tendency of the stems to become woody as they mature1 and the refusal of stock to eat sweet clover before they had become accustomed to the bitter taste4 ,another reason was the fact that until recently red clover could be grown in the eastern half of the ,united ,states without difficulty4 ,in northern ,kentucky the continuous growing of tobacco or of tobacco and wheat impoverished the soil to such an extent that crops no longer could be grown successfully4 ,upon the abandoned farms in this section sweet clover was introduced as a honey plant4 ,owing to the remarkable yields of tobacco that were obtained on such farms after sweet clover had been grown for a few years the acreage of this plant increased very rapidly4 ,for a number of years sweet clover has been grown on the ,selma chalk 7rotten-limestone7 soils of ,alabama and ,mississippi as a soil-improving crop4 ,at the present time it is being cultivated in practically every ,state1 and the acreage is increasing very rapidly4 ,after it had been demonstrated that sweet clover would grow successfully on soils too depleted for other crops1 many experiments were conducted to determine its value as forage4 ,it was found that it was not only a valuable soil-improving crop1 but that it made an excellent pasture and hay plant1 quite palatable and rich in protein4 ,white sweet clover comprises a very large percentage of the acreage seeded to sweet clover at the present time4 ,on this account this species ordinarily is referred to simply as sweat clover4 ,the yellow biennial species is designated as yellow sweet clover1 and the annual yellow species as bitter clover1 sour clover1 or annual yellow sweet clover4 ,this usage has been adopted in this bulletin4 ,illustration3 ,fig4 #a4--,seeds and seed pods of three species of ,melilotus and seeds of alfalfa3 #a4 ,white sweet clover2 #b1 biennial yellow sweet clover2 #c1 annual yellow sweet clover1 or sour clover2 #d1 alfalfa4 ,the small figures in each drawing show the natural size of the seed4 ,the venation and shape of the seed pods are important characters in distinguishing the different species of sweet clover4 ,the cultivation of sweet clover should be preceded by a thorough understanding of the requirements for obtaining a stand4 ,it can not be grown successfully on all soils1 as many assume from seeing it growing in uncultivated places4 ,neither will it thrive in many sections of the country without careful preparation of the seed bed4 ,sweet clover will not grow successfully in acid soils unless lime is applied1 but it will make a good growth in soils too low in humus to grow red clover1 provided the soil is neutral or alkaline4 ,sweet clover is an excellent plant to precede alfalfa1 as the large roots do much toward breaking up and aerating the subsoil4 ,contrary to the belief of many1 it will not inoculate the soil for alfalfa unless inoculation is applied to the sweet clover4 ,if1 however1 the soil contains but few inoculating germs1 the sweet clover will serve as a medium to inoculate it thoroughly4 ,,species ,,of ,,sweet ,,clover4 ,a number of species of sweet clover are found throughout the world1 and most of them are native to temperate ,europe and ,asia as far east as ,tibet4 ,white sweet clover1#a yellow biennial sweet clover1#b and yellow annual sweet clover#c are the only species which have given sufficient promise as forage and green-manure crops in this country to warrant growing them under cultivation4 #a ,melilotus alba ,dear4 #b ,melilotus officinalis 7,l47 ,lam4 #c ,melilotus indica 7,l47 ,all4 ,it is difficult for the average person to distinguish between the different species of sweet clover from an examination of the seeds or seed pods only4 ,the differences are indicated in figure #a4 ,where there is a question as to the identity of a sample of seed it should be sent to a ,state agricultural experiment station or to one of the seed laboratories of the ,united ,states ,department of ,agriculture for identification4 ,,white ,,sweet ,,clover4 ,white sweet clover 7fig4 #b7 is ordinarily referred to as melilotus or meliot in the ,south and merely as sweet clover in other portions of the country4 ,when soil conditions are favorable for germination1 sweet-clover seedlings will appear from one to two weeks after seeding4 ,on account of the biennial nature of the plants1 they do not seem to make much growth above ground the first month or six weeks after germination1 but during this time they are developing root systems rapidly and thus becoming established1 so to be able to withstand adverse conditions4 ,plants which have made no more than #b inches of top growth very often have produced roots #f inches or more in length 7fig4 #c74 ,the tap-root continues to develop rapidly throughout the growing season the first year1 and by autumn often reaches a length of #bd to #cf inches and a diameter of three-fourths to #a inch at the crown4 ,illustration3 ,fig4 #b4--;,a branch of white sweet clover1 showing the long1 loose racemes which bear white flowers4 ,after the root system becomes established the plants produce an upright1 branching1 leafy growth1 which under ideal growing conditions may reach a height of #dh inches the first season1 but more often #ah to #cj inches4 ,a large quantity of reserve food is stored in the tap-root the first season2 this reserve food enables the plants to make a rapid and vigorous growth early the following spring4 ,illustration3 ,fig4 #c4--,white sweet-clover plants collected from a plat six weeks from the date of seeding4 ,an extensive root system such as is shown here is often developed before much growth is made above ground4 ,toward the end of the growing season of the first year a number of buds1 which serve to produce the second year's growth 7fig4 #d71 are formed on the crowns of the plants4 ,after these buds are formed the plants may be clipped quite close to the ground1 as the buds are not developed until the plants have made sufficient growth to live through the winter4 ,during the second season sweet clover makes a rapid1 erect1 stemmy1 branching growth from #e to #aj feet in height1 the plants producing only a moderate number of leaves1 which drop as the seed matures4 ,a large number of loose racemes bearing white flowers 7see fig4 #b7 are produced during the flowering period1 which usually lasts from three to five weeks4 ,before sweet clover has made a growth of #ab to #ah inches it closely resembles alfalfa4 ,the plants may be distinguished from alfalfa by the absence of pubescence on the under side of the leaves and by their bitter taste4 ,when they are in bloom they may be identified easily by their long1 loose racemes of white flowers and their open1 coarse growth4 ,unlike alfalfa1 the seeds are ordinarily found singly in the pods4 ,two seeds may occasionally be found1 and very rarely three1 in a single pod4 ,,strains ,,of ,,white ,,sweet ,,clover4 ,a number of different strains of white sweet clover are to be found in the average field1 but most of them are not as marked or as conspicuous as the different strains of red clover4 ,the principal differences between strains of sweet clover are in leafiness1 habit of growth1 and date of blooming4 ,illustration3 ,fig4 #d4--;,buds produced on the crown of a sweet-clover plant at the end of the first season's growth4 ,these buds will produce the first crop the second season4 ,occasional plants are especially heavy seed producers and bear many pods containing more than one seed4 ,other plants bloom earlier than the average date for white sweet clover1 and it may be possible by selecting such strains to find one which matures early enough to produce two crops a season at high altitudes in the northern sections of the ,united ,states4 ,fields of an exceptionally early blooming strain were found in ,illinois1 ,iowa1 and ,north ,dakota in the summer of #aiaf4 ,the plants were different in type of growth from the ordinary white sweet clover1 being most conspicuous from the fact that they were in bloom during the first week of ,june1 which is at least three weeks earlier than the ordinary species should bloom in these localities4 ,illustration3 ,fig4 #e4--,root of white sweet clover 7on the left7 and of biennial yellow sweet clover 7on the right74 ,these roots were collected on ,october #bh1 #aiae1 at ,arlington1 ,va41 from adjacent plats seeded to cuts and sweet clover on ,april #aj1 #aiae4 ,note the difference in the size of the roots4 ,tubercles are present on the right-hand side of each root4 ,an annual white-flowered sweet clover was found in several localities in the fall of #aiaf4 ,the seed which produced these plants was grown in ,alabama4 ,these plants resembled ,melilotus alba in most respects except that they were strictly annual4 ,they flowered and matured seed abundantly in ,south ,dakota and ,north ,dakota4 ,it has not been determined whether this is a distinct species or merely an annual strain of the species mentioned4 ,,biennial ,,yellow ,,sweet ,,clover4 ,biennial yellow sweet clover ordinarily is referred to in the seed trade and among farmers in regions where it is grown simply as yellow sweet clover4 ,the plants of this species are somewhat more decumbent the first year1 and ordinarily with more deeply notched leaves than the white-flowering species4 ,yellow sweet clover usually grows from #c to #e feet in height4 ,this plant blooms from #aj to #ad days earlier than the white species1 and for this reason it is advisable to sow seed of both plants when they are to be used for bee pasturage4 ,on account of the finer stems of yellow sweet clover it is preferred in some localities for hay1 but since it does not produce as much forage as white sweet clover and there is much less demand for the seed1 it constitutes only a very small percentage of the total acreage4 ,the much larger root growth of the white species1 as illustrated in figure #e1 is desirable because of the additional quantity of hummus added to the soil4 ,the seeds of the yellow species may usually be distinguished from those of other species1 as some of them are slightly mottled with purple4 ,the shape of the calyx1 which is generally present on unhulled seed1 and the venation of the seed pods also distinguish it4 7,see fig1 #a47 ,,annual ,,yellow ,,sweet ,,clover4 ,annual yellow sweet clover1 more commonly known as sour clover or bitter clover1 is found chiefly in the ,south and ,southwest4 ,this plant is considered a noxious weed in grain fields throughout the ,southwest4 ,it is claimed that the flavor of the seed which is imparted to wheat can not be removed4 ,bakers decidedly object to this flavor1 stating that it injures bread4 ,sour clover is grown rather extensively as a green-manure crop in orchards in portions of ,arizona and southern ,california and when properly handled in these regions it has given profitable results4 ,as the seed is obtained from the screenings of wheat1 it is offered on the market at a very low price4 ,occasionally it is sold for the yellow biennial sweet clover4 ,seed of this plant should not be sown in any part of the ,united ,states except the extreme ,south or ,southwest1 and then only as a green hay manure crop4 ,where it is desired to plant sweet clover for pasturage or for the biennial white or biennial yellow species should be used4 ,,other ,,species ,,of ,,sweet ,,clover4 ,thirteen species of sweet clover have been tested by the ,office of ,forage-,crop ,investigations to determine their economic value4 ,with the exception of white sweet clover1 yellow biennial sweet clover1 and yellow annual sweet clover1 but four species in the somewhat limited tests have given sufficiently good results to merit special attention1 and none have so far proved superior to white sweet clover1 which is now extensively grown in many ,states4 ,a species of ,trigonella#d is often referred to as blue-flowered melilotus or blue-flowered sweet clover4 ,while this plant is closely related to the plants belonging to the genus ,melilotus1 it does not belong to this genus and therefore should not be called sweet clover4 ,it is an erect1 quite leafy1 very fragrant annual1 which produces a fair growth4 ,it may prove of value as a green-manure crop or as a catch crop under certain conditions1 but at the present time it is not to be recommended where sweet clover can be grown successfully4 ,in most tests ,trigonella has produced less forage than the better species of sweet clover4 #d ,trigonella caerulea4 ,,history4 ,sweet clover has been used as a honey plant and for forage and green-manure for more than #b1jjj years in the ,mediterranean region1 although it has never been considered of much importance4 ,the first authentic report of sweet clover in the ,united ,states was in #agci1 when ,gronovius stated in his ,flora ,virginica that it was collected by ,clayton4 ,cutler reported its presence in ,new ,england as early as #aghe1 and ,pursh in #ahad stated in his ,flora ,americ ,septentrionulis that it is found on the gravelly shores of rivers from ,pennsylvania to ,virginia4 ,elliott reported the presence of yellow biennial sweet clover in his ,sketch of the ,botany of ,south ,carolina and ,georgia in #ahbd1 and ,beck found the species ,melilotus leucantha#e in the ,northern ,states in #ahcc4 #e ,undoubtedly meaning ,melilotus alba4 ,in #ahef ,prof4 ,tutwiller1 of ,green ,springs ,academy1 ,ala41 received a small quantity of white sweet-clover seed from the secretary to the ,united ,states consul in ,chile4 ,part of this seed was planted by a young man named ,stendwick on his father's plantation on the prairie limestone belt1 where it flourished4 ,this plantation later became the property of ,j4 ,t4 ,collins who1 realizing the value of this plant1 sold seed to persons in many ,states4 ,not until recently has sweet clover been grown to any extent as a cultivated crop in this country4 ,,distribution4 ,while sweet clover is to be found growing in many countries and on all the continents of the world1 it is native to temperate ,europe and ,asia as far east as ,tibet4 ,it is grown to a limited extent in ,england1 while in the eastern part of ,scotland a small quantity is considered valuable in hay on account of its agreeable odor4 ,the famous ,cruyere cheese of ,switzerland owes its flavor to yellow sweet clover4 ,in ,germany it has given very good results when used as a green-manure1 while in parts of ,russian ,poland and ,austria-,hungary it is grown as a green-manure1 pasturage1 and hay crop on poor soils4 ,this plant is used for forage and as a soil-improving crop in the central provinces of ,india1 while sour clover1 commonly referred to as ,melilotus parviflora1 is credited with furnishing #ge per cent of the feed for the cattle of ,king ,island1 ,tasmania1 which produce the best beef and butter sold on the ,tasmania market4 ,illustration3 ,fig4 #f4--,outline map of the ,united ,states1 showing the localities where sweet clover is grown for forage or for green-manure4 ,each dot or circle indicates a county where #ej acres or more is grown under cultivation4 ,the solid dots represent white or yellow sweet clover2 the circles represent annual yellow sweet clover4 ,at the present time sweet clover is grown rather extensively as a field crop in the limestone regions of ,alabama1 ,mississippi1 and ,kentucky1 in northern ,illinois1 and throughout the western ,north-,central and ,mountain ,states 7fig4 #f73 in fact1 it is grown as a cultivated crop to some extent in nearly every ,state in the ,union4 ,comparatively little sweet-clover seed is sown in the ,atlantic ,coast ,states1 since there the soils are for the most part acid1 and heavy applications of lime will be necessary before sweet clover can be grown successfully4 ,it is questionable whether this plant will ever be of much importance in the ,south ,atlantic ,states1 as cowpeas1 soy beans1 and crimson clover will make a fair growth on those soils in their present condition4 ,the acreage of sweet clover probably will increase in the ,new ,england ,states1 where it should prove of value as pasturage and as a soil-improving crop on soils where red clover no longer can be grown4 ,sweet clover grows abundantly in the limestone regions of northwestern ,new ,york4 ,a much larger acreage of sweet clover is grown in northern ,illinois than in any other of the eastern ,north-,central ,states4 ,the conditions in the western ,north-,central ,states and in the ,mountain ,states appear to be particularly adapted to this crop4 ,it is in that part of the country that the largest acreage is found1 and1 with the exception of the limestone regions of the ,south1 that the least difficulty is experienced in obtaining a stand4 ,in those parts of the ,mountain and ,pacific ,coast ,states1 especially ,utah1 where it has not been tested carefully or where red clover or alfalfa can be grown successfully1 sweet clover is looked upon as a weed4 ,it may rightly be considered a weed in the irrigated regions of the ,west and ,northwest1 where it grows luxuriantly on ditch ,banks4 ,the dissemination of this plant in all parts of the country has been hastened by beekeepers who have seeded it in waste places for the production of honey4 ,,climatic ,,adaptations4 ,sweet clover is adapted to a wider range of climatic conditions than any of the true clovers and possibly alfalfa2 in fact1 it may be grown successfully in any portion of the ,united ,states except1 perhaps1 ,florida1 and in ,florida trials with biennial yellow sweet clover1 annual sweet clover1 and ,melilotus suaveolens have been successful4 ,apparently neither the high temperatures of the ,south nor the cold winters of the ,north severely affect the plants1 provided there is sufficient moisture in the soil4 ,comparatively little winterkilling is experienced in ,montana1 ,wyoming1 ,idaho1 and ,north ,dakota when the seed is sown in close drills or broadcasted4 ,although approximately #ej per cent of the sweet clover seeded in rows #c feet apart at ,moccasin1 ,mont41 was killed by the unusually severe winter of #aiae-af1 no winterkilling was noted in plats seeded in close drills4 ,sweet clover thrives in the more humid parts of the country1 as well as in the semiarid regions where the rainfall is but three-fifths of that required for the normal growth of such crops as red clover and timothy4 ,in the semiarid regions of the ,west sweet clover has proved to be somewhat more drought resistant than alfalfa4 ,,requirements ,,for ,,obtaining ,a ,,stand4 ,the requirements for obtaining a stand of sweet clover are somewhat exacting4 ,it is for this reason that so many failures have been experienced4 ,it must not be assumed1 because sweet clover is found growing luxuriantly in many waste places and on uncultivated land1 that a stand may be obtained by planting it at any time of the year1 in any manner1 and under all conditions4 ,throughout the eastern and southern portions of the country1 with the exception of a few regions rich in limestone1 much care must be used in the preparation of the seed bed1 the selection of seed1 and the manner of seeding if success is to be expected4 ,for this reason it is necessary to understand fully the requirements for obtaining and maintaining a successful stand4 ,,soils ,,suitable ,,for ,,sweet ,,clover4 ,sweet clover thrives on the adobe and granitic soils of the ,pacific coast2 upon the gumbo1 hardpan1 prairie1 and sandy soils of the western ,north-,central ,states2 and upon the heavy clay1 loam1 limestone1 and sandy soils of the ,south and ,east4 ,in fact1 it has been grown successfully on all the principal soil types of the ,united ,states where the soils were not acid and were well inoculated4 ,it grows luxuriantly on the ,selma chalk 7rotten-limestone7 soils of ,alabama and upon soils rich in calcium carbonate in many parts of the country where the lack of nitrogen and humus has caused large numbers of farms to be abandoned4 ,the plants thrive on newly exposed heavy clay soils and upon steep embankments where little else will grow4 ,sweet clover is more tolerant of poor drainage1 overflow1 and seepage conditions than alfalfa4 ,in irrigated sections1 especially where the reservoir system is in use1 large bodies of land are likely to become useless for the growth of alfalfa because of the rising of the water table4 ,on such areas sweet clover will make a vigorous growth4 ,however1 maximum growth is to be expected only on well-drained soil4 ,sweet clover will do well on many soils which are not fertile enough to grow red clover or alfalfa1 and it is on these soils that it will prove most valuable4 ,like many other plants1 it makes its best growth on fertile soils rich in calcium carbonate1 although it will make sufficient growth on poor soils which are not acid to warrant planting it on them4 ,many hilly pastures may profitably be seeded to sweet clover4 ,it will not only make a valuable addition to the forage of these pastures but will improve the soil so that grasses will grow more abundantly4 ,some of the best pastures in the ,middle ,west are composed of bluegrass1 timothy1 and sweet clover4 ,,resistance ,,to ,,alkali4 ,sweet clover grows successfully on soils in the ,west which apparently are too alkaline for grains or alfalfa4 ,the ,wyoming ,agricultural ,experiment ,station reports that it has obtained good yields of sweet clover on seepage land which is so strongly alkaline that no other plants except some of the native grasses will survive1 while the ,california ,agricultural ,experiment ,station found that sweet clover will withstand alkali to a remarkable degree4 ,prof4 ,f4 ,s4 ,harris1 agronomist of the ,utah ,agricultural ,experiment ,station at ,logan1 claims that it is one of the most alkali-resistant crops grown in ,utah1 and that in and #aiac and #aiad quite an industry developed in some parts of that ,state in growing sweet clover for hay and seed on land too alkaline for other crops4 ,in reply to a circular letter on the culture of sweet clover1 approximately #ajj county agents and extensive growers of this crop located in many parts of the ,west state that this plant is one of the most alkali-resistant plants grown in their respective districts4 ,in ,crook ,county1 ,oreg41 a good stand was obtained from ,april seeding in #aiae on a #bj-;acre demonstration field of sandy loam bottom land so strongly alkaline from black alkali that only salt grass was growing on it before it was planted to sweet clover4 ,this field pastured from #ah to #bh head of calves1 cows1 and horses from ,june #a to ,october #a without being irrigated4 ,sweet clover generally will grow on soils where salt grass#f will survive1 and it is very much superior to this grass as pasture4 ,after the drainage of water-logged land on which there is a surface accumulation of alkali1 it is the common practice in parts of ,utah to grow sweet clover for several years before planting alfalfa4 ,it is often stated that alkali land will grow less tolerant crops after sweet clover has been grown on it for a few years4 ,the long roots will open up the subsoil and cause better drainage1 thereby affording an excellent means for removing the salts from the soil1 as they are readily soluble in water4 #f ,distichlis spicata4 ,,need ,,of ,,lime ,,on ,,acid ,,soils4 ,sweet clover1 like many other legumes1 requires a soil containing an abundance of limestone if a maximum growth is to be expected4 ,throughout the world it makes a luxuriant growth only on calcareous soils4 ,on the black prairie limestone soils of ,alabama and ,mississippi it grows luxuriantly1 although in this region it is very seldom found on the outcroppings of red clay1 which are acid4 ,the distribution corresponds sharply with the line of demarcation between the black prairie soils and other soil types4 ,in some places sweet clover makes a vigorous growth on the ,selma chalk 7rotten-limestone7 soils1 while none is to be found on red post-oak clay but a few yards away2 yet sweet clover will grow on the red post-oak clay after the soil has received an application of lime4 ,it will thrive on the bald lime-rock spots and rotten-limestone hills of ,mississippi1 which are so barren that practically no other plants will survive4 ,thus it appears that lime is essential for the maximum growth of sweet clover in this ,region4 ,the reason for the exceptional growth of sweet clover in north-central ,kentucky is undoubtedly the fact that these soils contain an abundant supply of limestone4 ,the ,kentucky ,agricultural ,experiment ,station states that this area is the only portion of the ,state where sweet clover is being grown with general success without applying lime4 ,soils on which sweet clover is aggressive are almost invariably alkaline or but slightly acid4 ,this plant is often found in valleys of streams in localities where the soils are supposedly acid1 but such streams generally have their origin in limestone areas or flow through limestone regions1 and calcium carbonate is thus deposited in these valleys during flood periods with the sedimentary deposits from flood waters4 ,sweet clover often appears in deep cuts along highways or railroads in localities where the soil is known to be acid and where sweet clover has not previously grown4 ,in many of these cuts the acid soil has been removed and neutral or alkaline subsoil exposed1 or limestone has been used in ballasting or road making and the dust has blown on the exposed soil4 ,it is a very common occurrence to find sweet clover making an abundant growth along macadamized roads from which the wind has scattered the finely pulverized limestone4 ,an application of burnt lime or finely ground limestone has made the difference between success and failure in most experiments which have thus far been conducted on decidedly acid soils4 7,fig4 #g47 ,a number of sweet-clover experiments were performed on acid soils and on adjacent plats or fields of the same type of soil that had received applications of limestone varying from #a to #d tons to the acre4 ,there was a marked difference in the stands obtained and in the growth of the plants on the limed and unlimed areas4 ,in some cases the difference in growth was so marked that the last round of the lime spreader could be distinguished at some distance from the plats4 ,the stands were much heavier on the limed areas and the plants made from two to three times more growth than those on the unlimed plats4 ,yields of hay were doubled on soils that received only sufficient limestone to neutralize the acids in the surface soil1 although the yields were further increased when more limestone was added4 ,mr4 ,w4 ,e4 ,watkins1 county agent of ,allen ,county1 ,kans41 made counts of the number of plants which winterkilled during the winter of #aiad-ae on given areas of limed and unlimed soil4 ,it was found that from #ae to #ce per cent more plants winterkilled on the unlimed soil than on the limed areas4 ,that portion of the unlimed field on which the fewest plants winterkilled was found to have the lowest lime requirement4 ,on the unlimed areas with a low lime requirement #ae per cent more plants winterkilled than on the limed areas2 on those with a high lime requirement the increase in winterkilling was #cc per cent4 ,in the fall of #aiad the hay cut from the limed areas exceeded that from the areas with a low lime requirement by #fjj pounds per acre and exceeded that from the areas of high lime requirement by #d1jjj pounds per acre4 ,in ,july1 #aiae1 the increase in hay yield on the limed areas over that from the areas with a low and with a high lime requirement was #b1cjj and #i1djj pounds per acre1 respectively4 ,the area of high lime requirement returned a small yield in #aiad and no hay in #aiae4 ,in spite of the fact that sweet clover is as sensitive to soil acidity as red clover or alfalfa1 a large percentage of the acreage thus far seeded in the eastern half of the ,united ,states has been composed of acid soils1 and this soil acidity undoubtedly is responsible for a very large percentage of the failures with sweet clover in this section4 ,where sweet clover is to be sown on acid soils a sufficient quantity of lime should first be applied to at least neutralize the fields in the soil to a depth of #f inches4 ,an application of #a ton of burnt lime or #b tons of finely ground limestone will usually be sufficient for this purpose4 ,illustration3 ,fig4 #g4--,sweet-clover plants1 showing the effect of lime upon their growth4 ,the plants at the left represent the average growth on the unlimed portion of a field2 the plants at the right show the average growth on the limed part of the same field4 ,fields have been noted where sweet clover was making a fair growth on apparently acid soils4 ,such fields usually are rich in humus or phosphorus and are exceptional cases rather than the rule4 ,soil types which have slightly acid surface soils and alkaline subsoils will grow sweet clover successfully1 provided the acid soil is not more than #f to #ab inches in depth4 ,,fertilizers4 ,owing to the fact that sweet clover thrives on the barren ,selma chalk 7rotten-limestone7 hills of ,alabama and ,mississippi and grows abundantly on worn-out1 abandoned land in north-central ,kentucky1 it is often assumed that it will grow on soils too depleted in plant food to produce other crops4 ,these regions represent soils which have become exhausted primarily in nitrogen and humus as the result of continuous cropping with nonleguminous plants4 ,some of these soils contain sufficient phosphorus and potassium for fair crop production1 although this supply may be in such a condition that it will not become available fast enough to supply the needs of most crops4 ,sweet clover1 like all legumes1 has the power to extract nitrogen from the atmosphere1 and on account of its extensive root system it is able to obtain phosphorus and potassium from a larger area than most plants4 ,the large roots not only add a quantity of humus and nitrogen to the soil but they also open it up to a considerable depth1 thus providing better aeration and improving its physical condition4 ,improved physical condition causes the bacterial flora to increase and thereby indirectly causes a larger quantity of unavailable phosphorus and potassium to be made available for plant use4 ,on soils which are known to be low in phosphorus or potassium an application of fertilizer containing the necessary element should be made when sweet clover is sown without a nurse crop4 ,however1 when it is sown with a nurse crop or in the late summer or early fall on grain stubble1 the residues left in the soil from fertilizers applied to the nurse crop will1 under ordinary conditions1 be sufficient for the plants4 ,that sweet clover will respond readily to applications of phosphorus on soils low in this element has been well demonstrated by the farmers of ,livingston ,county1 ,ill4 ,in this county finely ground rock phosphate was applied to a portion of a number of fields at the rate of #a1ejj to #b1jjj pounds per acre4 ,the phosphate was thoroughly incorporated with the soil just before seeding oats and sweet clover4 ,in the growth of sweet clover there was a marked difference the following year between the treated and untreated portions of the fields4 ,those portions of the fields which received an application of phosphate not only contained many more plants on a given area1 but the vigor and growth of the plants were most marked4 ,on ,june #a the plants on the treated areas were #ab to #ae inches taller than those on the untreated parts of the fields4 ,this difference in the thickness of stand and the height of plants was so striking that the last round of the phosphate spreader was plainly distinguishable4 ,yields of sweet-clover hay have been increased as much as #b tons per acre from applications of barnyard manure4 ,such an increased yield would be equal approximately to #h tons of green-manure4 ,some people may consider it poor farm practice to apply manure to such crops as sweet clover1 but it is very probable that the cumulative effect of the increased yields of the following crops1 especially on soils low in organic matter1 will be greater than if the manure is applied to other crops4 ,heavy applications of manure to the preceding crop should also greatly benefit sweet clover4 ,,use ,,of ,a ,,nurse ,,crop4 ,if sweet clover is to become an important crop throughout the ,north-,central ,states it must necessarily be seeded with grain4 ,good success has been obtained by seeding sweet clover in the spring on winter grain or with spring grain on soil that was inoculated and not acid4 ,seed may be broadcasted in the early spring on winter grain when the ground is in a honeycombed condition1 or it may be sown later when the ground may be cultivated4 ,a large acreage of sweet clover is sown in the western ,north-,central ,states and in ,illinois in the spring with oats1 barley1 or wheat as a nurse crop4 ,early varieties of oats and spring wheat have given somewhat better results in portions of the ,northwest than barley4 ,in ,illinois oats are used almost entirely4 ,only a few fields were noted where flax had been used as a nurse crop1 but in these fields it was successful4 ,in wet seasons the sweet clover may make a growth sufficiently large to interfere seriously with harvesting the flax4 ,on this account this combination should be tested thoroughly in an experimental way before being recommended for general field practice4 ,in those sections of the country where the moisture supply is limited1 sweet clover should be sown without a nurse crop4 ,failure to obtain a stand is more likely to occur when the seed is sown with grain than when it is sown alone1 because during dry weather1 which is likely to occur when the grain is maturing1 the supply of moisture in the soil is apt to be insufficient for both crops4 ,when this condition prevails the clover will suffer badly and in some cases be killed4 ,when sweet clover is sown with a nurse crop it is strongly recommended that the grain be seeded at not more than two-thirds the usual rate4 ,this will give the sweet clover a much better chance than when a full seeding is made4 ,when severe droughts occur it may be necessary to cut the grain for hay if the stand is to be saved4 ,,choice ,,of ,,seed4 ,on account of the low germination of much of the sweet-clover seed offered for sale it is very important that seed be tested for germination before planting4 ,low germination usually is due to the fact that many of the seeds remain hard after they have been in the germinator or soil for a month or more4 ,the seed coats of hard sweet-clover seeds become permeable to water very slowly1 if at all1 in storage4 ,the germination of such seeds is greatly increased1 however1 when they are subjected for a time to alternating temperatures1 such as freezing and thawing4 ,it is on this account that unhulled seed1 which germinates poorly in the laboratory1 often will produce good stands when sown during the winter4 ,when sweet clover is to be sown in the spring it is very important that only hulled seed which germinates #ge per cent or more be sown4 ,as explained later under the heading ,seeding1 unhulled seed which has a low germination should be used for seeding only during the winter months1 so that there will be sufficient time for the alternating temperatures of winter and early spring to cause it to germinate during favorable weather4 ,hulled seed usually germinates much better than unhulled seed1 as is shown in ,table ,i4 ,table ,i4--,germination and hard seed content of samples of sweet-clover seed1 hulled1 and unhulled1 from different sources4 ,average percentage of-- ,number of ,description4 samples4 ,germination4 ,hard ,seed4 --------------- ---------- ------------ ---------- ,kind of seed3 ,hulled #bcg #ec4be #ah4g ,unhulled #de #aa4h #gj4i ,source of seed3 ,southern #bb #ad #fj ,northern #bb #cg #dc ,imported #bh #ef #ab ,table ,i shows that northern-grown seed germinates better than northern-grown seed and imported seed better than either4 ,the low germination of the southern-grown seed is probably due to the fact that a very large percentage of it is flailed out and sown in the hull4 ,northern-grown seed generally is thrashed with either a grain separator or a clover huller4 ,imported seed always is hulled4 ,in hulling seed the rasps or concaves of the machines scratch the seed coats sufficiently to permit water to penetrate them1 so that the germination is greatly increased4 ,apparently there is no reason why southern-grown seed when it is properly hulled should not germinate as well as northern-grown seed4 ,since the ,ames scarifying machine 7fig4 #h7g has been placed on the market1 it is possible to buy scarified seed4 ,this machine is so constructed that the seed is forced through a conveyor1 part of which is covered with sandpaper4 ,when the seed comes in contact with the sandpaper it is scratched1 so that water will penetrate the seed coats4 ,when this machine is run properly the germination of seed is greatly increased1 but when carelessly operated germination may be lessened1 as many of the seeds may be broken4 #g ,this machine was invented by ,prof4 ,h4 ,d4 ,hughes1 of the ,iowa ,state ,college at ,ames4 ,a ,united ,states patent covering this device has been issued and dedicated to the free use of the public4 ,illustration3 ,fig4 #h4--;,ames hulling and scarifying machine4 ,the retarded germination of sweet-clover seed may be overcome by soaking it in commercial concentrated sulphuric acid for #bj minutes4 ,it should then be washed quickly1 using running water if possible1 as sulphuric acid becomes very hot when mixed with small proportions of water4 ,a great deal of water therefore is necessary in order to lessen the danger of burning4 ,the seed should be dried quickly by spreading it out on a floor or canvas1 and it should be stirred at intervals4 ,unhulled seed should never be treated with sulphuric acid4 ,when only a small quantity of sulphuric acid comes in contact with the hulls a very high temperature will result and the seed will be killed4 ,the treatment of seed with sulphuric acid for seeding on a field scale is not to be recommended1 in view of the fact that as good or better results may be obtained by using scarified seed4 ,it is very important that seed of the desired species be obtained4 ,many lots of sweet-clover seed offered for sale on the market consist of mixtures of the yellow and white species1 and many samples also are adulterated with alfalfa4 ,seed which is simply labeled sweet clover should never be purchased1 as seed so labeled may be any one of the several varieties offered for sale4 ,it is always best to state the specific kind of seed ordered and then submit a sample to either your ,state ,agricultural experiment ,station or one of the seed laboratories of the ,united ,states ,department of ,agriculture#h for identification before purchasing4 #h ,samples of seed may be submitted for analysis or identification to the ,seed ,laboratory of the ,united ,states ,department of ,agriculture at ,washington1 ,d4 ,c41 or to any of the following laboratories maintained through the cooperation of the ,department3 ,branch ,seed-,testing ,laboratory1 ,agricultural ,experiment ,station1 ,columbia1 ,mo42 ,branch ,seed-,testing ,laboratory1 ,agricultural ,experiment ,station1 ,baton ,rouge1 la42 ,branch ,seed-,testing ,laboratory1 ,oregon ,agricultural ,college1 ,corvallis1 ,oreg42 ,branch ,seed-,testing ,laboratory1 ,purdue ,university1 ,la ,fayette1 ,ind42 ,branch ,seed-,testing ,laboratory1 ,california ,agricultural ,station1 ,berkeley1 ,cal4 ,the ,seed ,laboratory of the ,united ,states ,department of ,agriculture during the winter of #aiae-af obtained #agb trade samples of sweet-clover seed and1 as may be seen from ,table ,,ii1 many of the samples were not true to name4 ,table ,,ii4--,trade samples received in response to requests for white sweet clover seed4 ,key to ,columns ,a ,white sweet clover4 ,b ,biennial yellow sweet clover4 ,c ,white and biennial yellow sweet clover4 ,d ,annual yellow sweet clover4 ,number of ,seed when tested ,seed labeled-- samples4 found to be-- ,alfalfa and-- ,a ,b ,c ,d ,a ,b ,c ,white flowering sweet clover1 white sweet clover1 or ,holhara clover1 or ,melilotus alba4 #adg #ia #aj #bh -- #ac #a #d ,sweet clover #bb #f #d #b #e #e -- -- ,not labeled #c #a -- -- #b -- -- -- ---- ---- ---- ---- ---- ---- ---- ---- ,total #agb #ih #ad #cj #g #ah #a #d ,,preparation ,,of ,,the ,,seed ,,bed4 ,sweet clover requires a well-settled and firm seed bed1 with just sufficient loose soil on the surface to permit the seed to be well covered4 ,when the seed is sown in the spring on winter grain the seed bed usually is in good condition4 ,at this season of the year the seed may be sown1 so that it will be covered by freezing and thawing weather4 ,it may be sown also when the ground is in condition to cultivate and then may be harrowed or drilled in4 ,when the seed is sown with spring grain the seed bed is not as firm as it should be for the prompt germination and establishment of the young clover plants4 ,if sown in this manner the soil should be worked into a fine condition and firmed as much as possible4 ,it is good practice to roll the ground with a corrugated roller after seeding4 ,better stands are usually obtained by seeding on fields that have been disked and harrowed than on those that have been plowed4 ,when sweet clover is seeded without a nurse crop it should not be sown on freshly plowed land which has had no opportunity to settle4 ,the land preferably should be plowed several months before the seed is to be sown1 and then worked at intervals with soil packers or harrows4 ,double disking and harrowing just previous to seeding are to be strongly recommended in preference to plowing at this time4 ,when sweet clover is to be seeded in the fall on grain stubble1 the ground should be disked and worked into good condition as soon as the grain can be removed4 ,if the seed is sown immediately the field should be rolled after seeding4 ,fall-plowed ground ordinarily makes an ideal seed bed for spring seeding4 ,soil which has been previously planted to a cultivated crop1 such as corn1 is usually put in sufficiently good condition for sweet clover by disking4 ,good success has been attained by merely broadcasting the seed on sandy soil and scratching it in with a harrow4 ,such a seed bed appears to be ideal when the seed can be covered sufficiently to insure plenty of moisture4 ,it must be remembered that young sweet-clover plants are not drought resistant and that every precaution should be taken in seasons of drought or on laud which drought affects badly to so prepare the seed bed that the largest quantity of moisture will be conserved4 ,excellent stands have been obtained at times by double-disking native prairie sod and either covering the seed with a harrow or sowing it with a drill4 ,,seeding4 ,the proper time to seed sweet clover should be determined by the germination of the seed1 the climatic conditions of the region1 and the condition of the seed bed at the time of sowing4 ,when growing under natural conditions1 seed which has lain in the ground over winter germinates in sufficient quantity during the following spring to produce a stand4 ,it is therefore assumed that since this seed has passed the winter on or in the ground and has produced a good stand the following spring1 sweet clover may be sown at any time of the year and a satisfactory stand obtained4 ,little is thought of the enormous number of seeds which shatter from a single plant and fall on an area not exceeding #e or #f feet in diameter4 ,single plants have produced as many as #cej1jjj seeds 7the approximate number in #a pounds71 or about #aj1jjj seeds for each square foot of ground covered4 ,it matters little how many of these seeds germinate in the fall they mature or during the following winter1 when the seedlings will be killed by freezing1 for there will be enough viable seeds left in the ground to germinate when conditions are favorable in the spring4 ,conditions are very different when sweet clover is sown on cultivated soil at the rate of #e to #bj pounds of seed to the acre--#be to #ajj seeds to the square foot4 ,when this quantity is sown1 it is necessary that it be planted at such a time that the greatest number of seeds will germinate and produce plants4 ,,hulled ,,sweet-,,clover ,,seed4 ,hulled seed makes up a large percentage of the sweet-clover seed sown4 ,the germination of hulled seed varies considerably1 although ordinarily it is higher than that of unhulled seed4 ,seeding experiments conducted at ,arlington1 ,va41 with seed which germinated #hj per cent show clearly that seed which germinates well should not be sown during the winter months in those sections of the country where midwinter thaws are likely to occur1 and especially in sections south of the latitude of southern ,ohio4 ,in these experiments seed was sown during each month of the winter4 ,good stands were obtained only on those plats which were sown in the latter part of ,february and during ,march and ,april4 ,at least #ge per cent of the seed sown during ,november1 ,december1 and ,january germinated on warm days during winter thaws and was killed by later cold weather4 ,notwithstanding the fact that sweet-clover seedlings will endure fairly low temperatures1 seed germinating more than #ej per cent should not be sown during the winter months1 and preferably not more than a week previous to the average date for the last severe freeze4 ,no data have been secured on winter seeding in those portions of the ,united ,states where open winters do not occur4 ,it is probable that in those sections the winters are sufficiently cold to prevent germination before spring4 ,good results may be obtained by winter seeding1 but as usually no trouble is experienced in those sections in obtaining a stand by seeding as soon as the soil can be worked in the spring1 it is strongly recommended that seeding be done with hulled seed1 which germinates well at this time of the year4 ,many excellent stands have been obtained by seeding late in the spring1 but in most sections seeding at this time is not as certain to produce a good stand as earlier seeding4 ,late spring seeding may be preferable when the ground is weedy and the clover is to be seeded without nurse crop4 ,under these circumstances a crop of weeds may be destroyed before seeding4 ,very good success has been obtained in the ,southern and ,central ,states1 and in some of the ,northern ,states1 by seeding sweet clover in the late summer or early autumn4 ,when there is sufficient moisture in the soil for germination and when good seed is used1 better stands have been obtained by seeding about eight weeks before severe frosts are to be expected than from spring sowing4 ,this is particularly true in regions where late spring droughts or severe summer droughts are likely to occur4 ,seeding at this time may be done after an early crop has been harvested and when weeds are not likely to be troublesome4 ,plants from fall seeding mature from #aj days to two weeks later the following season than plants from spring sowing of the same year4 ,the later time of maturing is an advantage1 in that the plants will be ready to cut during better haying weather4 ,the root growth is not as large from fall seeding as from spring seeding1 and therefore not quite as much humus is added to the soil4 ,late fall seedings are very likely to be injured from heaving on wet clay soils4 ,,unhulled ,,sweet-,,clover ,,seed4 ,unhulled sweet-clover seed is sown principally in ,kentucky1 ,alabama1 and ,mississippi4 ,on the limestone soils of regions1 which appear to be naturally adapted to sweet clover1 very good results are obtained by using unhulled seed4 ,it is not because southern-grown unhulled seed germinates better than northern-grown unhulled seed that better stands are obtained in the ,south from it1 but it is mainly because southern farmers better understand the somewhat exacting conditions necessary for obtaining a stand with this kind of seed4 ,unhulled sweet clover contains a large percentage of hard seeds which will not germinate until they have been in the soil for some time and have been subjected to varying temperatures4 ,seeding experiments have been conducted at ,arlington1 ,va41 where unhulled seed which contained #ij per cent of hard seed was sown during each month of the winter4 ,good stands were obtained on those plats seeded at the rate of #bd pounds 7#c pecks7 of seed to the acre during ,december and ,january1 and fair stands on the plats seeded at this rate in ,february4 ,later seedings failed to produce a stand4 ,a large percentage of the unhulled seed sown in the ,south is seeded during ,january and the first part of ,february4 ,good stands are seldom obtained from unhulled seed south of the latitude of ,washington1 ,d4 ,c41 when the seed is sown later than the middle of ,february4 ,the use of unhulled seed has usually been attended with failure in the northern portion of the ,united ,states1 although occasionally good stands have been obtained the following spring from late fall seeding4 ,this failure is in part due to the fact that the seed has been sown in the spring and at a tine when only seed germinating well should be used4 ,when unhulled seed is to be sown north of the latitude of ,washington1 ,d4 ,c41 it should be sown not later than ,february #ae1 and preferably earlier4 ,observations show that fairly good stands may be obtained by seeding during the winter1 but care should be taken not to sow seed earlier than necessary on land which is subject to washing4 ,farmers should have no trouble in purchasing hulled seed1 and therefore it is recommended that only hulled seed which germinates well be sown4 ,,rate ,,of ,,seeding4 ,the rate at which sweet clover should be seeded varies with the germination of the seed1 the condition of the seed bed1 the climatic conditions of the region1 and the method of seeding4 ,throughout the humid sections of the eastern ,united ,states sweet clover ordinarily is seeded at the rate of #ae to #bj pounds of hulled seed to the acre4 ,from #ab to #ae pounds should be ample where the seed bed is in good condition and the seed germinates #ge per cent or more4 ,in ,illinois1 the western ,north-,central ,states1 the ,mountain ,states1 and the ,pacific ,coast ,states good stands are generally obtained by sowing #aj to #ab pounds of hulled seed to the acre4 ,in eastern ,washington it is claimed that from #e to #h pounds to the acre are sufficient for good stands4 ,when sweet clover is grown under irrigation1 #h to #aj pounds of hulled seed usually are sufficient1 and from #b to #d pounds per acre are enough when seeded in rows from #b to #d feet apart4 ,of unhulled seed #c to #f pecks 7#bd to #dh pounds7 or #bj pounds of hulled seed are usually sown in the ,south for pasturage or hay4 ,in any region at least #aj pounds more of the unhulled than of hulled seed should be sown to an acre4 ,unless annual yellow sweet-clover seed is thoroughly cleaned it should be sown at the rate of #be to #cj pounds to the acre4 ,,methods ,,of ,,seeding4 ,the methods used for seeding red clover or alfalfa in any particular region will be suitable for seeding sweet clover4 ,good results have been obtained by broadcasting the seed on winter grain in the spring when the ground is in a honeycombed condition4 ,perhaps a better method is to wait until the ground can be worked and then to broadcast and cover the seed with a harrow or to sow it with a drill4 ,unhulled seed is usually broadcasted1 since it is necessary to sow it before the ground is in condition to be worked4 ,unless the hulls have been rubbed smooth1 some difficulty may be experienced in seeding it evenly with a drill4 ,when sweet clover is to be sown with spring-seeded grain or when it is to lie sown without a nurse crop it may be drilled in or sown broadcast and covered with a harrow4 ,better stands are generally obtained with a smaller quantity of seed when it is sown with the drill than when it is broadcasted on honeycombed ground4 ,when the seed is sown at the time the grain is planted1 the grass-seeder attachment of the drill commonly is used4 ,in some sections the end-gate seeder is used almost entirely4 ,when the seed is sown by either of these methods it may be seeded alone or mixed with the grain4 ,when only the clover seed is sown with a drill1 the alfalfa and clover seed drills are to be preferred4 ,sweet-clover seed may be mixed with some inert substance of approximately the same size and weight and sown with an ordinary grain drill4 ,finely cracked corn1 cracked wheat1 or coarse bran often are used for this purpose4 ,when one portion of sweet clover is mixed with two portions of a filler find the drill is set to sow one-half bushel of wheat1 it will usually sow from #ae to #bj pounds of sweet clover to the acre4 ,as this quantity will vary with the different types of drills1 it is necessary to test each drill1 so that the seed may be mixed with the filler in such proportions that the desired quantity will be sown4 ,the drill may be tested by blocking it up1 so that the geared wheel is off the ground1 and this wheel may be turned a sufficient number of times to establish a definite portion of an acre4 ,the seed that runs through can then be weighed and the rate per acre determined4 ,the rate may be determined more accurately by plugging up the grain tubes or by tying a small sack on each tube and pulling the drill for a specific distance over the field to be sown4 ,the jar of the drill will cause it to drop more seed than when it is blocked up and run by hand4 ,it is often desired to seed sweet clover on land which can not be cultivated4 ,when sown on such land it is recommended that unhulled seed or seed that contains a large percentage of hard seed be used and that it be broadcasted during the winter4 ,the subsequent freezing and thawing will cover many of the seeds and cause them to germinate4 ,it is a good plan to scatter in deep gulleys mature plants that have not shattered all their seed4 ,the branches of these plants will help to hold the seed in place until it germinates and the young plants become established4 ,seed may be scattered on native prairie ground in the late winter1 but unless it is trampled into the ground by live stock disappointing results are likely to be obtained at first4 ,fair results have been secured by planting seed with disk drills on prairie sod after it had been double-disked in the early spring4 ,this method should be used in preference to broadcasting the seed and depending on cattle to trample it in4 ,mr4 ,george ,hummer1 of ,prairie ,point1 ,miss41 reports good success in his locality by simply broadcasting #a peck of unhulled seed on ,bermuda-grass sod not later than ,january #a4 ,,inoculation4 ,excepting soil acidity1 lack of inoculation probably is responsible for more failures with sweet clover than any other one cause4 ,when sweet-clover plants are not inoculated they must depend upon the available nitrogen in the soil for their supply1 and as the crop is grown for the most part on soils low in nitrogen the plants can not be expected to make more than a small growth4 7,fig4 #i47 ,illustration3 ,fig4 #i4--,white sweet clover at ,arlington1 ,va41 showing the effect of inoculation upon their growth4 ,the plants at the left represent the average growth on the inoculated plats2 those at the right the average growth on the plats not inoculated4 ,the plats had been previously limed and were seeded on the same date4 ,arny and ,thatcher1 at the ,minnesota ,agricultural ,experiment ,station1 obtained #aj times as much dry matter in the tops and seven times as much in the roots of sweet-clover plants which had been grown on thoroughly inoculated soil as from plants ,which had been grown on soil not inoculated4 ,moreover1 the plants grown on the inoculated soil contained #aag pounds more nitrogen to the acre than those grown on the uninoculated soil4 ,experiments in many other sections of the country1 and especially in the northeastern quarter of the ,united ,states1 where but little sweet clover or alfalfa has thus far been grown1 show that inoculation is very essential to success4 ,ordinarily it is not necessary to inoculate sweet clover when it is to be planted on land where alfalfa1 bur-clover1 or black medic thrives1 because the same strain of inoculating germs inoculates all of these plants4 ,however1 when this closer is to be planted on land where none of the plants inoculated by this strain of the organism have been grown1 inoculation should be provided4 ,in localities where sweet clover or other plants inoculated by the same strain of bacteria thrive1 the early growth has at times been made much more vigorous by inoculating the soil or seed thoroughly4 ,it is not safe to assume that a certain piece of soil is inoculated because any one of the plants inoculated by the same strain of the organism is growing or has been grown on other fields in the same vicinity4 ,many fields have come under observation where sweet clover was a failure because the plants were not inoculated1 when plats or fields of alfalfa growing near by were abundantly inoculated4 ,there are several methods of inoculating sweet clover1 any one of which when properly applied should give good results4 ,,the ,,soil-,,transfer ,,method4 ,the soil-transfer method of inoculation consists in scattering over the field to be seeded #bjj to #djj pounds to the acre of soil collected from sweet-clover1 alfalfa1 or bur-clover fields where the healthy plants show an abundance of tubercles on the roots4 ,it is strongly recommended that this soil be scattered on a cloudy day or in the early morning or in the evening and immediately harrowed or disked into the ground1 as the sun's rays are very injurious to the inoculating germs4 ,it is a good plan for the person scattering the soil to walk directly in front of the harrow4 ,when this practice is followed little harm can be done by the light4 ,to facilitate even scattering1 the soil may be mixed thoroughly with two or three times its weight of other soil1 preferably from the field where the sweet clover is to be sown4 ,soil used for inoculating sweet clover does not necessarily have to be scattered on the land just previous to sowing the seed4 ,it may be scattered a few months or a year in advance of the time the sweet clover is to be seeded and be just as effective as if it were scattered at a later time4 ,in general1 where sweet clover is to be seeded in the spring on winter grain1 the inoculation should be applied before the grain is sown4 ,good success has been obtained by drying in a dark place soil containing the inoculating germs1 sifting it1 and running it through the fertilizer compartment of a grain drill4 ,when this method is employed it is not necessary to use as much soil as when it is scattered broadcast4 ,a comparatively new method which has given successful results calls for dampening each bushel of seed and spreading it on a cloth1 paper1 or cement floor1 where half a gallon of throughly inoculated soil from sweet-clover or alfalfa plants may be sifted over it4 ,some people prefer to add a trace of glue or sugar to water1 so that more of the soil will adhere to the seed1 although some soil will remain on the seed if the glue or sugar is not used4 ,when only this quantity of soil is used it should be collected from around the roots of sweet-clover plants which are abundantly inoculated4 ,such soil may be collected in the fall and kept until spring in a cool1 dry1 dark place with no injury to the inoculating organisms4 ,seed treated in this manner should be kept in the dark and should be sown as soon as possible after treating4 ,,the ,,pure-,,culture ,,method4 ,the pure-culture method has the advantage of greater case of transportation and freedom from danger of introducing harmful pests upon the farm4 ,inoculation by pure cultures may be carried out in either of two ways3 7#a7 ,a bottle of pure culture of the proper kind of bacteria is opened and the culture mixed with a convenient quantity of water2 this diluted culture now is mixed thoroughly with a considerable quantity of soil1 preferably from the field where the legume is to be sown2 the treated soil is then distributed in the same manner as when inoculation is made by the soil-transfer method4 7#b7 ,a pure culture of the proper kind of bacteria should be applied to the seeds in such a way that they will all be moistened4 ,the seed should then be permitted to dry in a shady or dark place and should be planted as soon as possible after it is dry4 ,drying may be facilitated by adding dry1 sifted soil1 preferably from the field where the seed is to be sown4 ,inoculating organisms very often die within a week after the seed is inoculated4 ,it is highly desirable1 therefore that the inoculation be made the day the seed is sown4 ,inoculated seed never should be dried in the sun4 ,the question is often asked whether it is advisable to inoculate seed with pure-culture method and sow it on honeycombed ground in the spring4 ,no experiments have thus far been completed to determine the advisability of this procedure4 ,some inoculation would probably result from this practice1 because the bacteria on that portion of the seed next to the ground would be protected from the sunlight and would in a short time under ordinary conditions be covered by the freezing and thawing of the soil4 ,while it is hardly possible to obtain as complete inoculation by this practice as by other methods1 it is to be preferred to no inoculation4 ,,treatment ,,of ,,the ,,stand4 ,the manner in which a stand of sweet clover is handled should depend somewhat upon the method and date of seeding and the purpose for which it is sown4 ,climatic conditions should also be taken into consideration and the handling of the crop governed accordingly4 ,,treatment ,,the ,,first ,,season4 ,the most serious objection to seeding sweet clover in the spring without a nurse crop is weeds4 ,in many sections of the country seeds will take as much water from the soil and make as much or more shade than a crop of grain4 ,in spite of the fact that sweet clover will withstand more adverse conditions than red clover or alfalfa1 a heavy growth of weeds will greatly retard the growth of the plants and in some cases kill most of them4 7,fig4 #aj47 ,on plats sown in ,april without a nurse crop at ,arlington1 ,va41 it was necessary to mow weeds five times during the summer of #aiae in order to keep them partly checked4 ,where it is necessary to mow a field so many times the plants are not only checked or killed1 but as much time is required for this work as would be necessary to harvest a crop of grain4 ,this trouble may be overcome in part by pasturing the sweet clover the first season1 but even then during wet weather it may be necessary to cut the weeds at least once before the plants become well enough established to turn live stock on the field4 ,the plants should at no time be clipped closer than #e inches from the ground4 ,after a field of sweet clover has become well established1 it may be pastured throughout the summer and fall4 ,close grazing should be avoided during the summer1 or the plants may be killed1 but they may be pastured fairly close to the ground in the autumn1 as it does not appear as necessary to provide a winter covering as is the case with red clover4 ,close pasturing or clipping late in the fall has had a marked effect on the growth of the plants the following spring on some fields and no apparent effect on the stand and growth of the plants on other fields4 ,a portion of a field in ,livingston ,county1 ,ill41 was clipped close to the ground in the late fall of #aiae4 ,on ,june #a1 #aiaf1 the stand was somewhat heavier on the unclipped part of the field4 ,more noticeable than the thickness of the stand was the fact that the plants on the unclipped portion were #h to #aj inches higher than those on the clipped area4 ,it is reasonable to believe that plants going into the winter with no protection are more likely to be injured than those having some protection4 ,on the other hand1 many fields in different parts of the country have been closely clipped or pastured in the late fall with no noticeable injury4 ,because of the value of the hay or pasturage in the late summer and autumn of the year of seeding1 it is strongly recommended that the first year's growth be utilized4 ,if the field be cut for hay it is well to leave a #d-;inch or #e-;inch stubble1 as this will serve to catch drifting snow during the winter1 thereby adding to the protection against winterkilling4 ,if the field is not pastured the first season and weeds are not troublesome1 a cutting of hay may be made when growth ceases in the fall4 ,illustration3 ,fig4 #aj4--,white sweet-clover plant 7at the left71 showing the effect of a heavy growth of weeds4 ,had the weeds not been present the plant at the left should have been larger than the one at the right1 as the seed was sown two weeks earlier and the other conditions for growth were ideal4 ,four-fifths of the plants on the plat which had a heavy growth of weeds were entirely killed4 ,when sweet clover is seeded with grain1 moisture conditions should serve to determine whether the grain should be permitted to ripen or be cut for hay4 ,when untimely droughts appear the plants may be killed if the grain is not cut as early as possible4 ,in the ,south and in some sections of the ,eastern and ,north-,central ,states where the soil contains an abundance of limestone and is well inoculated1 a cutting of hay may usually be obtained after a grain crop has been harvested4 ,in other sections of the ,north in only exceptionally favorable weather will more than pasturage be obtained after the grain is cut4 ,,treatment ,,the ,,second ,,season4 ,one of the special advantages of sweet clover is that it produces good pasturage somewhat earlier in the spring than most forage crops4 ,in the ,north1 with the exception of the extreme northern portion of the ,united ,states1 it will furnish a cutting of hay in ,june or excellent pasturage until that time and a crop of hay or seed in late summer4 ,in the ,south two cuttings of hay and a seed crop may be harvested4 ,after maturing seed the plants die4 ,it is a common practice in many sections to pasture the crop until about ,june #aj1 when the stock is removed and the plants are permitted to mature seed4 ,if the plants have not been grazed closely they should be clipped at this time1 so that the seed crop will ripen more evenly4 ,sweet clover may be pastured during the entire second season's growth1 provided sufficient stock is kept on the field to prevent the growth from becoming woody4 ,if the plants become coarse the pasture may be clipped1 leaving an #h-;inch stubble1 so as to induce a new growth which will be more palatable4 ,if it is desired to have the pasture reseed itself stock should be removed at least eight weeks before heavy frosts are expected1 or only sufficient stock should be permitted to remain on the pasture to keep some of the plants in check4 ,,sweet ,,clover ,,in ,,mixtures4 ,very little sweet clover thus far has been grown in mixtures with other crops4 ,a few farmers have sown red clover and sweet clover together1 but such a mixture has no advantage over sweet clover seeded alone for hay1 as sweet clover should be cut at least two ,weeks before the red clover is ready to harvest4 ,sweet clover is being seeded to some extent on native prairie sod in the ,northwest1 where it is claimed it adds greatly to the value of the native grasses for pasturage4 ,a thin seeding of sweet clover is often desired in bluegrass pastures on this account4 ,one of the best pastures in eastern ,iowa consists of a mixture of bluegrass1 timothy1 and sweet clover4 ,the ,mississippi ,agricultural ,experiment ,station recommends a mixture of ,johnson grass and sweet clover4 ,in this mixture the first cutting will consist of almost pure sweet clover1 while the second and third cutting's will be a mixture of those plants4 ,a number of southern farmer have had good success in seeding sweet clover on ,bermuda-grass sod4 ,the ,new ,jersey ,agricultural ,experiment ,station has obtained excellent results from a mixture of ,dwarf ,essex rape and sweet clover1 and also by the addition of soy beans to this mixture4 ,it was found that by seeding #f pounds of rape and #aj pounds of sweet clover per acre an abundance of nutritious pasturage was produced and that pigs preferred this mixture to alfalfa4 ,when soy beans were added it was seeded at the rate of #a bushel of soy beans1 #f pounds of ,dwarf ,essex rape1 and #ah pounds of sweet clover4 ,the soy beans were drilled by themselves1 and the rape and sweet clover were mixed and seeded with a press drill4 ,brood sows made a gain of from three-fourths to #a pound a day during ,july on this mixture without additional feed and gave unusual evidence of thrift and vigor4 ,illustration3 ,fig4 #aa4--;,a cornfield1 showing the effect of fall and spring plowing in killing sweet clover that had made but one year's growth4 ,the portion of the field at the left was plowed in the autumn1 while that at the right was plowed the following spring1 after the plants had started growth4 ,the corn is #d inches high4 ,,eradication ,,of ,,sweet ,,clover4 ,some farmers hesitate to plant sweet clover on their farms for fear they will have difficulty in eradicating it when the fields are planted to other crops4 ,the results obtained annually by hundreds of farmers are sufficient proof that there is no foundation for such fear2 in fact1 farmers are experiencing much difficulty in cutting the first crop the second season so high that the plants will not be killed4 ,the new crop of sweet clover1 unlike that of red clover and alfalfa1 must come from the buds left on the stubble1 so when the plants are cut below these buds they will be killed4 ,as sweet clover is a biennial1 the plants die as soon as the seed crop is produced4 ,when the first year's growth of sweet clover is to be turned under for green-manure it is recommended that the field be plowed after the plants have made some growth the following spring rather than in the fall of the year of seeding4 ,when the first year's growth is plowed under the same fall many of the plants will not be entirely covered1 and these will made a vigorous growth the following spring4 ,when the plowing is delayed until the plants have made some growth the following spring no trouble will be experienced in eradicating them4 7,fig4 #aa47 99 99 99 99 99 ,,publications ,,of ,,the ,u4 ,s4 ,,department ,,of ,,agriculture ,,relating ,,to ,,forage ,,crops4 ,,available ,,for ,,free ,,distribution ,,by ,,the ,,department4 ,cowpeas4 7,farmers' ,bulletin #cah47 ,alfalfa4 7,farmers' ,bulletin #cci47 ,soy ,beans4 7,farmers' ,bulletin #cgb47 ,red ,clover4 7,farmers' ,bulletin #dee47 ,alfalfa ,seed ,production4 7,farmers' ,bulletin #die47 ,forage ,crops for the ,cotton ,region4 7,farmers' ,bulletin #eji4 7 ,vetches4 7,farmers' ,bulletin #eae47 ,vetch ,growing ,in the ,south ,atlantic ,states4 7,farmers' ,bulletin #ebi47 ,crimson ,clover3 ,growing the ,crop4 7,farmers' ,bulletin #eej47 ,crimson ,clover3 ,seed ,production4 7,farmers' ,bulletin #fdf47 ,the ,field ,pen as a ,forage ,crop4 7,farmers' ,bulletin #fij47 ,bur ,clover4 7,farmers' ,bulletin #fic47 ,button ,clover4 7,farmers' ,bulletin #gcj47 ,the ,clover leafhopper and ,its ,control in the ,central ,states4 7,farmers' ,bulletin #gcg47 ,,for ,,sale ,,by ,,the ,,superintendent ,,of ,,documents1 ,,government ,,printing ,,office1 ,,washington1 ,d4 ,c4 ,leguminous ,crops for ,green ,manuring4 7,farmers' ,bulletin #bgh47 ,price1 #e cents4 ,lespedeza1 or ,japan clover4 7,farmers' ,bulletin #dda47 ,price1 #e cents4 ,crimson ,clover3 ,utilization4 7,farmers' ,bulletin #egi47 ,price1 #e cents4 ,alfalfa ,production3 ,pollination ,studies4 7,department ,bulletin #ge47 ,price1 #e cents4 ,red-,clover ,seed ,production3 ,pollination ,studies4 7,department ,bulletin #bhi47 ,price1 #e cents4 ,variegated ,alfalfa4 7,bureau of ,plant ,industry ,bulletin #afi47 ,price1 #aj cents4 ,leguminous ,crops for ,hawaii4 7,hawaii ,agricultural ,experiment ,station ,bulletin #bc47 ,price1 #aj cents4 ,,washington 3 ,,government ,,printing ,,office 3 #aiag 99 99 99 99 99 ,transcribers ,note ,all illustrations moved to avoid splitting paragraphs4 ,sweet clover and sweet-clover variants retained4