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GROWING CRIMSON CLOVER.[1]

L. W. Kephart,
Scientific Assistant, Office of Forage-Crop Investigations.

CONTENTS.

Crimson clover is an annual or winter annual true clover,resembling common red clover in size and general appearance,the most noticeable difference being the flower heads, which are long,narrow, and pointed instead of short, spherical, and compact (fig. 1).The individual flowers of this clover are commonly of a rich scarletcolor, and as the heads are borne mostly on the ends of the stems,a field of crimson clover in full bloom presents a strikingly brilliantappearance. Because of the color of the flowers, crimson clover isoften termed "scarlet clover," although it is also known, less commonly,as "French clover," "Italian clover," "German clover," "incarnateclover," and "annual clover." It is the only annual trueclover that is of more than incidental agricultural importance inthe eastern United States.

Probably the most important characteristic of crimson clover isits ability to grow and make its crop during the fall and early spring,when the land is not occupied by the ordinary summer-grown crops.In sections where it succeeds, it can be sown following a grain cropor in an intertilled crop in late summer and is ready to harvest forhay, to pasture, or to turn under as green manure in time to plowthe land for spring-seeded crops, such as corn or cotton. South ofcentral Delaware it may even be cut for seed and the stubble plowedunder in time for seeding a quick-maturing strain of corn. Becauseit can be grown during the offseason of the year, crimson cloveris one of the most economical legumes for green manuring, and it has[ 4 ]been largely used for that purpose in the regions to which it isadapted. The many uses to which this crop may be put merit a carefulstudy of the best methods of establishing a stand of this clover onthe farm.

Fig. 1.—A single plant of crimson clover.

HISTORY AND ADAPTATIONS.

Crimson clover is a native of Europe, where it is cultivated as aforage and green-manuring crop in Italy, France, Spain, Germany,Austria, and Great Britain. Large quantities of crimson-clover seed[ 5 ]are exported from Europe to the United States, especially from thedistricts of central France, where crimson clover is the premier leguminousforage plant.

Crimson clover was introduced into this country as early as 1818,and the seed was widely distributed by the United States PatentOffice in 1855. The plant was at first regarded more for its ornamentalvalue than as a forage plant, however, and it was not untilabout 1880 that its value for agricultural purposes began to beappreciated.

Fig. 2.—Map of a part of the United States, showing theregion where crimson clover is most widely grown.

At present crimson clover is grown most widely in the lighter sandyareas of the Atlantic Coastal Plain, where the soil is not very richand the winters are not severe. (Fig. 2.) The plant does not withstandeither extremecold or extreme heat,and its culture istherefore limited toregions which enjoyat some time duringthe year a long periodof relativelymild, moist weather.Ordinarily, thisclover does not survivethe winter inlatitudes north ofsouthern Pennsylvania,while in someof the SouthernStates it is frequentlykilled by dry, hotweather in the fallor spring. It succeeds well in the humid regions near the Gulf ofMexico and in the Pacific Northwest, but in these areas it is notwidely grown.

Normally, crimson clover is a winter annual comparable to winterwheat; that is, it is planted in the fall, lies more or less dormantover winter, grows rapidly in the spring, and dies, after going to seed,early in the summer. Where the summers are not too hot it can beplanted in the spring and grown as a summer crop, but for this purposeother clovers are usually preferred.

VARIETIES.

Crimson clover is exceedingly variable both in color of flower andin time of maturity. These variations are particularly noticeable infields planted from a mixed lot of seed, the flowers presenting arange in color from nearly pure white to a deep purplish red and the[ 6 ]seeds a difference in date of ripening of more than a month. Sincecrimson clover is thought to be mainly self-pollinated, it is easy tofix these qualities by selection and to establish definite varieties.

In Europe six or seven different varieties of crimson clover arerecognized and sold by seedsmen, varying from extra early crimsonflowered to, extra late white flowered and from very hardy to non-hardy.By the use of a succession of these varieties the Europeanfarmer is able to spread his harvest over six or seven weeks instead ofhaving it concentrated within a few days, as in America. Similarly,the culture of the plant has been extended northward from Italy toSweden by means of hardy strains. A wild form of crimson cloverhaving yellowish flowers and hairy foliage occurs in southern andeastern Europe and in England, but it is not of economic value.

In America no sharply defined varieties of crimson clover are recognized,except a white-blooming variety which is sold in the Southand is two weeks later than the ordinary crimson-flowered sort.Hardy strains have been developed and used in a small way inMassachusetts and Ohio, but these are not commercially available.

USE IN THE ROTATION.

SEEDING IN INTERTILLED CROPS.

In former years a large percentage of the crimson-clover acreagewas seeded in corn or other intertilled crops at or shortly after thetime of the last cultivation. In most of the crimson-clover area itis possible to make such a seeding, obtain a good growth during thefall and early spring, and mow or plow under the clover in time, forbreaking up the land for another crop of corn. This has been thestandard method of growing this clover, and it is still the leadingpractice in many of the older sections. Corn in the summer withcrimson clover in the winter is a cheap and convenient method ofgrowing a cash crop and a restorative crop the same year, and thereputation of crimson clover as a crop increaser is largely based onthis simple rotation. Instances are by no means rare where the yieldof corn has been gradually increased from 10 bushels per acre to ashigh as 70 bushels by this means.

The difficulty with this method is the possibility of the stand ofyoung clover failing through drought. The growing corn makes aheavy demand on the soil moisture, and if there is not enough moisturefor both clover and corn the latter gets the larger share and thetender clover plants are likely to succumb. Because of the riskinvolved, farmers in the upland sections are seeking other and morereliable methods of seeding, and the sowing of crimson clover incorn is gradually decreasing.

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Where the danger from fall drought is not serious, crimson clovermay be sown in corn at the time of the last cultivation or when thecorn leaves have just begun to wither. South of central Virginiathere is likely to be much hot weather after the corn is laid by, inwhich case it is best to delay the seeding of the clover until afterthe first rain. The appearance of a field of crimson clover seeded incorn the previous summer is shown infigure 3.

Fig. 3.—Crimson clover in an old cornfield. The clover was seeded in the corn at thelast cultivation. A fodder stack is to be observed in the middle foreground. Thecornstalks have been removed to avoid difficulty in mowing the clover.

South of southern Virginia crimson clover can be seeded in cotton,provided the field is free from crab-grass and other weeds and thesoil is not too dry. In the extreme north of the cotton belt the seedmay be sown at the last working of the cotton; farther south thisoccurs too early and it is necessary to wait for a rain, which oftencomes at about the time of the first picking.

Crimson clover may be seeded in practically any of the cultivatedtruck crops which receive their last cultivation from 8 to 12 weeksbefore the first frost. It is not practicable to seed the clover in latepotatoes, sweet potatoes, or other root crops, as the digging in thefall practically destroys the clover.

Ordinarily, crimson clover does not succeed when sown in cowpeas,sorghum, or watermelons, owing to the heavy shade cast bythese crops. It can, however, be seeded in tobacco, tomatoes, cultivatedsoy beans, and cantaloupes.

SEEDING AFTER AN EARLY-MATURING CROP.

Seeding crimson clover in an intertilled crop is successful mostlyon sandy soils, which can easily be prepared for seeding even in mid-summer.On clay soils and in weedy fields this method of seeding[ 8 ]is likely to be unsatisfactory. Such soils are usually hard and dryin August and can with difficulty be brought into condition for aseed bed, with the result that a large percentage of such seedingsfail. A better plan on clay soils, and on sandy soils in many cases,is to seed the crimson clover on specially prepared ground fromwhich all other crops have been removed. Such ground can bemade as fine and firm as desired. Furthermore, the clover afterplanting does not have to compete with another crop for the soilmoisture. This method is somewhat more troublesome than plantingin intertilled crops, but the greater certainty of getting a standmore than offsets the greater cost. Planting crimson clover onspecially prepared ground has extended the culture of the plantto regions where it was not hitherto grown and is increasing thereliability of the crop in sections where it has been long established.

In the ordinary rotation, crimson clover follows a crop of smallgrain. However, it may follow any crop that is removed 8 to 10weeks before frost, or it may be seeded on fallow ground. Groundfrom which early potatoes have been removed is especially favorablefor the establishment of a stand of this clover. The residualeffect of the fertilizers used on potatoes is partially responsible forthis, while the well-settled seed bed, which requires only levelingand harrowing, also presents favorable conditions for the crimson-cloverseedlings.

In many parts of the South crimson clover can be seeded in cornstubble if an early variety of corn has been used. Although thereis some risk that the clover may not make enough growth beforewinter if seeding is delayed until the corn is harvested, the dangerof losing the stand is not as great as if the clover were seededearlier, while the corn was standing.

Crimson clover is sometimes seeded after a grass or clover cropif the rainfall in July is sufficient to cause the sod to decay. Inthe far South it can be planted after peanuts, while in all sectionsit can be sown as a catch crop on land where cotton or other cropshave died early in the season.

REQUIREMENTS FOR OBTAINING A STAND.

Probably the difficulty most commonly experienced in growingcrimson clover is failure to obtain a satisfactory stand. Sometimesthe seed does not germinate well; more commonly good germinationis secured, but the seedlings wither and die before they can becomeestablished. Frequently not more than 50 per cent of the plantssurvive the first three weeks, while a complete failure of the crop isa common risk even in the sections where crimson clover is mostwidely grown.

The most common cause of failure to obtain a stand is hot, dryweather after planting. The seedlings of crimson clover are tender,[ 9 ]succulent, and shallow rooted and are easily killed by lack of moisture.Unfortunately, in most of the crimson-clover area the weatherduring late August and early September is very likely to be hot anddroughty, making the planting of the clover at that time ratherhazardous. Some farmers attempt to avoid this difficulty by plantingeither in early summer or in October, after the fall rains; thereis danger, however,that the plants willmake too much ortoo little growth tosurvive the winter.In the long run it isprobably better toplant at the regulartime and dependupon thorough preparationof the seedbed to offset anydeficiency in therainfall.

SOILS.

Crimson clovercan be grown successfullyon almost anytype of soil if it isreasonably rich, welldrained, and suppliedwith organicmatter and theproper inoculatingbacteria. Probablytwo-thirds of thecrimson-clover acreageis found on thesandy soils of theAtlantic CoastalPlain, but the cropis not necessarily restrictedto sandysoils and is in factincreasing in importance on the red-clay soils of the Piedmont regionand in the limestone valleys of Virginia and Tennessee.

Fig. 4.—a crimson-clover failure on ground too poor inhumus.

Crimson clover has been an important factor in increasing yieldson soils that have been abused, but it is not a crop for land which isnaturally very poor. It does not do well on rough, newly cleared[ 10 ]areas, raw subsoil, Hard, dry clay, or sterile sand. (Fig. 4.) Forsuch soils soy beans, cowpeas, and velvet beans are better suited andshould be used for the first three or four years until crimson clovercan be successfully grown. Crimson clover can be made to growon poor soils, provided they are specially prepared by liming, manuring,and inoculating. In general, however, crimson clover is a cropfor maintaining soils which are already fairly productive ratherthan one for inducing productivity in soils where it is quite lacking.If there is any doubt whether the soil is suitable for crimson clover,a small plat should be prepared under field conditions and plantedone year for trial.

PREPARATION OF THE SEED BED.

To secure a full, even stand of crimson clover with any degree ofregularity the seed bed should be well and thoroughly prepared.The soil should be firm, moist, well settled, and fine on top. Onlyindifferent success can possibly be expected if the seed is scattered onland which is loose, dry,and full of hard lumpsand trash. A loose seedbed dries out quickly,heaves during the winter,and on some soils blowsand washes badly.

Fig. 5.—A corrugated roller or pulverizer, an excellentimplement for preparing the seed bed forcrimson clover.

On the other hand, theseed bed should not betoo hard, for althoughthis clover often growssuccessfully on soil whichwould be too solid for corn, there must be at| least enough loose soil onthe surface to cover the seed. Thorough preparation is the very bestinsurance against failure of the stand through drought or winterkilling,and the most successful growers sow crimson clover on landas well prepared as that for wheat.

To secure a fine, firm seed bed without drying out the surface soil,the land should be prepared with as few operations as possible. Asingle working when the soil is in a moist, crumbly condition isbetter than half a dozen workings when the soil is too wet or toodry. In very sandy soils, or soils which do not form a crust, theonly preparation needed is to keep down the weeds.

An excellent tool for making the seed bed is the corrugated rolleror pulverizer (fig. 5). This implement is an improvement over theold plain roller for breaking clods and is unexcelled for keeping thesurface soil moist. It can be used after plowing and again beforeplanting, and even after planting if the soil needs to be compacted.Rolling of some kind to firm the soil is especially important on sandysoils, but it is equally beneficial on clay soils if they are cloddy.

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When clover is seeded in an intertilled crop, such as corn, cotton,or tomatoes, the customary cultivation received by these crops isordinarily sufficient preparation for crimson clover. In sandy soilthe clover is often seeded without any immediate preparation, but alight stirring with a harrow-toothed cultivator is desirable if theground is hard. If the clover is to be used for hay or seed, the precedingcrop should be laid by level rather than in ridges. This willfacilitate cutting the clover.

Where crimson clover is seeded after a crop of small grain, thestubble should be plowed or disked as soon as possible after thegrain is cut. Stubble land dries out quickly, partly because the soilis suddenly left bare and partly because of the drain on the soilmoisture by the crops of ragweed and other coarse-growing weedswhich always follow a grain crop. Unless the soil is cultivated atonce it becomes very difficult to obtain anything like an ideal seedbed for crimson clover. This difficulty is usually more pronouncedafter oats and barley than after rye and wheat. Ordinarily the bestpractice is to disk the grain stubble within a week after harvest andharrow every week, or at least after every rain, in order to settle theground, destroy the weeds, and assist in holding the moisture pendingthe time of seeding the clover. Plowing the stubble is more expensivethan disking and requires that the ground be allowed to settlefor a month or six weeks in order to secure a firm seed bed. Plowingis an advantage in a wet season, because plowed ground dries readily;it is a disadvantage in a dry season for the same reason.

FERTILIZERS.

On moderately rich soil the fertilizer applied to the precedingcrop is sufficient to produce a good crop of crimson clover. This isespecially true where the clover follows such crops as potatoes ortomatoes, which ordinarily are heavily treated with fertilizers. It isimportant to realize, however, that crimson clover has a very shortperiod of growth, and that to make a vigorous growth it must have agood supply of plant food. On sandy soils where fertilizers have notrecently been applied it is often the practice to apply from 150 to 200pounds of acid phosphate, with some potash fertilizer if it can beafforded. On clay soils 200 or 300 pounds per acre of acid phosphateordinarily are sufficient. On many soils a light application of nitrateof soda will assist materially in giving the young clover plants agood start and often will enable them to withstand the effects of alate drought or severe winter which otherwise might have injuredthe stand. If the seeding has been delayed, as by waiting for suitablerains, an application of not more than 75 pounds of nitrate of sodaper acre will stimulate the young plants and enable them to make abetter growth before winter.

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Fertilizer is usually applied at seeding time, but a few farmers havebeen found who apply it as a top-dressing very early the followingsummer, giving as a reason that there is then no loss from winterleaching and that by this method the plants are nourished at thetime they are making their most vigorous growth. Such top-dressingsof fertilizer should not be made while the leaves are wet with rainor dew. Where stable manure is applied to crimson clover verymarked results follow. It may be spread just before seeding whenthe clover is not grown in an intertilled crop, or it may be applied asa top-dressing in winter or very early spring.

The more vigorous the growth that can be induced by the applicationof suitable fertilizers the more marked will be the increase inthe yield of the succeeding crops. On soil in a low state of productivitythe use of a reasonable amount of fertilizer will often enablea successful crop of clover and succeeding crops to be produced, wherehad not the fertilizers been applied the clover would have failed.Furthermore, the following crop, particularly if it be corn, wouldalso fail to give the increased yield which follows a successful standof crimson clover.

An application of barnyard manure will be found to be especiallyeffective in obtaining a stand of crimson clover on any thin, galledspots in the field. The manure should be worked into the groundbefore seeding, and, if possible, a second application as a top-dressingshould be given a day or two after planting. The top-dressingstimulates the seedlings and if strawy helps to protect them from theAugust sun.

LIME.

Crimson clover is not as dependent on lime as red clover andalfalfa, being more like alsike clover in this respect. It does notthrive on soils which are very "sour," but on well-drained soils ina productive condition crimson clover frequently makes a vigorousgrowth, even though the soil may show a high lime requirement.The stands are usually more uniformly good over the limed partsof such fields than on the unlimed parts, although it is sometimesquestionable whether the benefit derived from liming is profitable.Liming is more often desirable on clay soils than on sandy soils,and usually gives better results when used in conjunction with fertilizersthan when used alone. On light sandy soils deficient in humusburnt lime may be actually injurious. In considering the advisabilityof applying lime one must not lose sight of the need of lime on thepart of such other crops as corn, cantaloupes, or peaches, whichare either grown with or follow the clover. Inasmuch as the effectof liming varies greatly in different localities, it is suggested thatsmall plats be treated experimentally at different rates before anyconsiderable areas are limed.

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INOCULATION.

A large part of the value of all clovers lies in their ability toutilize the nitrogen of the air and add it to the soil. Whengrown on rich land, the clovers, like many other plants, use thenitrogen already present in the soil and are not stimulated to contributeany to their own support or to the support of other crops.To enable the clover to use the nitrogen in the air the presence ofthe proper nodule-forming bacteria in the soil is necessary.

Fortunately, most of the soils in the crimson-clover sections appearto be already inoculated, and artificial inoculation is not oftennecessary, except on soils new to the crop. Crimson clover is inoculatedby the same strain of bacteria which occurs on the roots ofthe other true clovers; consequently, a field which has produced agood stand of red, mammoth, alsike, white, hop, Carolina, rabbit's-foot,or buffalo clover is usually inoculated sufficiently for crimsonclover. Sweet clover, Japan clover, and bur clover are not trueclovers and are inoculated by a different strain of bacteria.

The importance of inoculation is well shown by an experimentconducted by the Alabama Agricultural Experiment Station. Inthis experiment yields of 4,057 and 6,100 pounds of crimson-cloverhay were secured on inoculated soils, while on corresponding areaswhich were not inoculated the yields were 761 pounds on one areaand nothing on the other.

The soil can be inoculated artificially by means of pure culturesof the bacteria or by the transfer of a small quantity of soil fromanother clover field.[2] The latter method is the more certain, but isopen to the danger of introducing noxious weeds, insects, and plantdiseases, especially if the soil is brought from a distance. Thepresence of stem-rot in many sections makes the use of soil especiallydangerous. This disease can, be carried with the soil from field tofield.

SEEDING.

TIME OF SEEDING.

Crimson clover is usually sown between August 15 and October 1,the general rule being to plant about 60 days before the first killingfrost is expected. South of Virginia crimson clover can be seeded aslate as November 1, although if planted late more seed should beused and a light dressing of nitrate of soda applied, in order tostimulate the young plants. Seeding earlier than August 1 is seldomadvisable unless the crop is sown with some other crop the shade ofwhich will hold it back.

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The exact date of planting depends almost entirely upon the moisturecontent of the soil. The principal condition to avoid is plantingwhen the soil contains just enough moisture to germinate the seeds,but not enough to keep the plants growing. Usually it is better toplant when the soil is quite dry than when it is slightly moist, for indry soil the seeds, if properly buried, lie without germinating andare ready to grow vigorously at the first rainfall. The most favorabletime for seeding is just before or just after a good rain, when thesoil is moist enough to form a ball in the hand.

RATE OF SEEDING.

The ordinary rate of seeding crimson clover is 15 pounds per acre,although the rate varies according to conditions. From 12 to 15pounds per acre are usually sufficient when growing the crop for seedor when the soil is unusually rich. On poor soil, dry soil, or on soilwhich has not previously produced crimson clover 18 to 22 poundsof seed give better assurance of a stand. Heavy seeding is also desirablewhen planting late in the season or when a heavy crop iswanted for green manure early in the spring.

Theoretically, 2 pounds of seed per acre would provide six plantsfor every square foot, which is a satisfactory stand. Under ordinarycircumstances, however, it is necessary to allow for some of the seedbeing too deep, or too shallow, or failing to germinate, and for acertain percentage of winterkilling. It is also well to have a fairlythick stand of the young plants, so that the ground may be wellcovered during the early fall and thus prevent soil washing and thegrowth of winter weeds.

METHODS OF SEEDING.

The most common method of seeding crimson clover in intertilledcrops is to scatter the seed broadcast with a rotary seeder or by hand.(Fig. 6.) In order to place the seed on a fresh, moist seed bed it iscommonly broadcasted immediately behind the cultivator at the lastcultivation and is covered 'at once by a second cultivator. In tallcorn the seed may be sown from horseback, the ears of the horse beingcovered with small bags to prevent the entrance of the flying seed.Slightly more seed is required when seeding in tall corn, as some seedcatches in the corn plants. When seeding in cotton care must be takento avoid injury to the opening bolls, which are easily knocked off ortorn. This is best done by seeding by hand, covering the seed with apiece of brush dragged down the rows.

In low-growing truck crops and on fallow ground crimson clovercan be seeded with a wheelbarrow seeder. This implement distributesthe seed more evenly than can be done by hand or with the rotaryseeder, especially when planting a mixture of crops. The wheelbarrow[ 15 ]seeder being somewhat awkward to handle is better adaptedto smooth, level fields than to hillsides.

Fig. 6.—Seeding crimson clover in corn at the last cultivation.

Probably the very best method of seeding crimson clover is withthe special clover or alfalfa drill. Where enough clover is grownto warrant its use this implement is to be highly recommended. Theseed is sown in 4-inch rows at just the proper depth and with theright pressure, and the fertilizer is placed exactly under each row,where it will be immediately available to the seedlings. Drilledclover requires less seed than broadcasted clover and produces a moreeven and certain stand.

In place of the special clover drill an ordinary grain drill equippedwith a clover-seed attachment can be used with good results. Specialspouts should be arranged to lead from the clover-seed box back ofthe shoes or disks, in order to deposit the seed directly in the furrow.Chain furrow closers are best for covering the seed, as they leavethe furrows broad and flat instead ofV shaped and lessen the dangerof the seedlings being covered with soil during a hard rain.

For use in intertilled crops there are several types of 1-row drills,the best for this purpose being the 5-hoe drill equipped with presswheels.

Crimson-clover seed must be covered, but not too deeply. In mostsoils it is not enough to depend on rain to effect a covering. An inchin sandy soils and half an inch in clay soils appear to be about theright depth. Shallow planting gives the best results in wet seasonsand deep planting in time of drought. Broadcasted seed should becovered with a spike-tooth harrow or a weeder rather than a heavyharrow or a shovel cultivator. A harrow made of fairly stiff brushis often useful in loose soil.

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CHOICE OF SEED.

As a rule, fresh crimson-clover seed is of good viability, and failureto secure a stand is not often caused by failure of the seed togrow. Unlike most clovers, crimson-clover seed absorbs water readilyand sprouts quickly. There are practically none of the hardseeds which are so frequent in red clover and sweet clover, and agermination of 90 per cent in 48 hour's is not uncommon. The seeddeteriorates rapidly, however, and when more than 2 years old rarelyshows a germination in excess of 50 per cent. Sometimes, whenstocks of commercial seed are low, old seed finds its way to the market,and this, when planted, gives poor results. Old seed can usually bedetected by the dull-brown appearance of the seed coat as contrastedwith the bright, shiny, pinkish or greenish yellow color of fresh seed.Brown seed, however, is sometimes caused by weathering during harvest,and such seed is not objectionable unless the weathering hasbeen excessive.

A common impurity in crimson-clover seed is green, shrunken, andimmature seed, caused by harvesting the crop before it is ripe. Crimson-cloverseed does not germinate readily until it takes on a yellowishtinge; therefore, green seed should be rejected.

Crimson-clover seed is larger and plumper than red-clover seedand if properly cleaned should not contain seeds of dodder or thesmaller seeded weeds. Frequently, however, it does contain the seedsof field peppergrass, yellow trefoil, evening primrose, sheep sorrel,wild geranium, buttercups, mustards, and other weeds which blossomin early summer.

UNHULLED SEED.

There is a growing belief among farmers that they are less likelyto lose a stand of crimson clover through drought if they sow the seedin the hull rather than use the hulled seed as it ordinarily appears onthe market. It is claimed that the hulls hold the moisture to someextent and carry the seedlings over the critical day or two followinggermination, while some farmers assert that the unhulled seeds requiremore moisture for germination, and the seeds therefore do not sproutuntil there is enough moisture in the soil to keep the plants growing.Unhulled seed is bulky and is not often handled by commercial seedsmen,although one large grower sells the unhulled seed in compressed,bales similar to small cotton bales. It usually can be secured fromneighboring farmers, however, or is easily saved at home. The seedcan be harvested with a stripper from the standing crop in the fieldor the mature crop can be cut and thrashed like an ordinary graincrop. For local planting on a small scale unhulled seed is thecheapest and most accessible form of crimson-clover seed.

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Unhulled seed is somewhat difficult to sow, because the hairy hullsstick together in masses and can not be scattered uniformly. Toavoid this trouble the seed may be mixed with moistened earth orwith lime, or may be sown with a blower similar to those used onsmall forges. A better plan is to sow on a windy day, throwing theseed vertically into the air and allowing the wind to scatter it.

Of unhulled seed of the best quality, 100 pounds contains about 1bushel (60 pounds) of clean seed. The common grades, however, areusually more chaffy and require 120 to 180 pounds to make a bushel.From 2 to 3 pounds of unhulled seed are therefore regarded as equivalentto 1 pound of hulled seed. A bushel of unhulled seed, even whenwell packed down, weighs only 6 to 10 pounds and contains about 4pounds of seed. The appearance of both hulled and unhulled crimson-cloverseed is shown infigure 7.

Fig. 7.—Hulled seed of crimson clover of a common commercial grade and unhulledseed gathered with a homemade stripper. (Natural size.)

USE OF A NURSE CROP.

In order to protect the crimson-clover seedlings from the hot sunof late August it is a common practice in some sections to plant withthe clover a small quantity of some quick-growing crop like buckwheat,cowpeas, rape, or turnips. A thin stand of these heavierleaved plants furnishes an ideal shade for the young clover, and onsoils which are inclined to bake it prevents the formation of a crust.The nurse crop must be seeded lightly, usually not more than halfthe regular rate, as the ordinary stand shades the ground so[ 18 ]completely as to destroy the crimson clover. On hot clay soil in the Piedmontregion the chances of obtaining a stand of clover are abouttwice as good with a nurse crop as without one.

Buckwheat is the principal nurse crop northward from Washington,D. C. A common rate of seeding is 2 to 3 pecks of buckwheat in15 pounds of crimson clover. If the planting can be made in Julythe buckwheat usually has time to ripen before frost and thus paythe cost of starting both stands.

In the cotton belt cowpeas have been used successfully, especiallywhen seeding on fallow ground. They are seeded broadcast at therate of one-half bushel per acre. There is ordinarily not enough timefor the cowpeas to mature, but they add to the value of the stand forfall pasturage and protect the clover from severe weather in the winter.Both cowpeas and buckwheat have the merit of being able togrow on poor soil.

Dwarf Essex rape has been used as a nurse crop in a few caseswhere the clover was to be pastured by hogs or sheep in the fall.From 2 to 3 pounds of rape, sown in August, furnishes sufficientcover for a nurse crop. Cowhorn turnips, winter kale, and mustardare also satisfactory nurse crops if planted at a rate not exceeding1 pound of seed per acre. If the clover is to be saved for seed theselatter crops are objectionable, as a few plants will live over winterand ripen at the same time as the clover.

Where a nurse crop can not be grown conveniently, the crimson-cloverseedlings can be protected from the sun by a light top-dressingof straw, spread just after the seed is sown.

SEED MIXTURES.

Crimson clover is frequently grown in combination with wintergrain, hairy vetch, or other forage crops having a similar period ofgrowth. The mixed crop is less liable to lodge than the single crop,cures more readily in damp weather, and usually furnishes a heavieryield. Another advantage of the mixed crop is that if either shouldfail the other will serve as a cover crop during the winter and bringsome return the following spring. Mixed crops are not desirableif the clover is to be saved for seed.

South of central Virginia crimson clover is usually grown in combinationwith winter oats. An early variety of oats, such as theFulghum, or a late variety of clover, such as the white blooming, isusually the best, as the oat crop matures somewhat later than the ordinarycrimson clover. The customary rate of seeding is 15 poundsof the clover and 2½ bushels of oats per acre. In Delaware andeastern Maryland the most popular companion crop for crimsonclover is winter wheat, although barley makes a desirable hay cropand is sometimes used. Eye is not desirable for hay, but it is[ 19 ]probably the best of the grains for green manure, as it is hardy, vigorous,and starts growth early in the spring. Rye and wheat are seeded atthe rate of 1 bushel per acre with the customary quantity of crimsonclover. The accompanying illustration (fig. 8) shows a field seededto a mixture of crimson clover and wheat. Usually the grain iswell headed, but in the milk or soft-dough stage, when the clover isready to cut, the yield of the mixed crimson clover and grainis often 25 to 50 percent greater thanthat of the cloveralone.

Fig. 8.—Crimson clover and wheat in mixture. In theforeground the crop has been cut and fed green to stock.The remainder was cut the next day for hay. The grainprevents the crimson clover from lodging.

Hairy vetch andcrimson clover aresometimes grown together,seeding at therate of 20 poundsand 10 pounds peracre, respectively.As both these plantsare likely to lodge ingood soil, however,one of the grains isusually included, acommon seedingmixture being oats 2bushels, hairy vetch12 to 15 pounds, andcrimson clover 5pounds. Bur clover,black medic, andother winter-growinglegumes aresometimes found inmixtures with crimsonclover, although such mixtures generally occur by accident ratherthan intent. Black medic and crimson clover make' a particularlygood combination on rich soil.

In most of the crimson-clover area the cultivated grasses, such astimothy, redtop, and orchard grass, are not commonly grown. However,where these grasses flourish they may well be seeded at thesame time as the crimson clover, provided the latter is planted notearlier than September 15. In some sections Johnson grass andBermuda grass make useful combinations with crimson clover, thegrasses making most of their growth in the summer and the cloverin the fall and spring.

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TREATMENT OF THE STAND.

Ordinarily no special treatment is required after seeding and theclover goes into the winter without any further handling. If thegrowth is so rank that there is danger of the plants being too succulentto survive the winter, the tops can be reduced by light grazingwith small animals, such as calves, sheep, or chickens, or by mowingwith the cutter bar of the mowing machine set high. If the stand isbackward, it may be stimulated by a light application of nitrate ofsoda. It is said that a thin stand can be thickened by grazing lightlywith sheep, as the grazing induces heavier stooling. The aim shouldbe to carry the clover into the winter with well-hardened leafy stemsand with a well-established root system to withstand heaving out inthe spring.

In fields which are to be saved for seed a wise precaution is to goover them early in the spring and chop out the weeds. If wild onionand other weeds are chopped off in April, they do not make enoughgrowth by May to contaminate the seed crop.

MALADIES.

The only disease seriously affecting crimson clover is the cloverstem-rot, root-rot, or wilt, a disease resembling the stem-rot, or wilt,of lettuce and other plants. This disease is prevalent in nearly allthe crimson-clover States and sometimes does considerable damage.The stem-rot affects the clover at all seasons, but is more noticeablein the spring, when it sometimes causes large spots of clover suddenlyto wilt and fall. Occasionally an entire field is affected, butthe disease is most prevalent in low, rich spots. Examination of theplants discloses a rotting off or decay of the stems close to the ground,followed immediately by the appearance on the stems of small blacklumps, or sclerotia, about the size of clover seed. These sclerotia area means of spreading the disease and are often harvested in the hayor in the seed crop. The only known remedy for the stem-rot is tocease growing clover or alfalfa on an infested field for three or fouryears, substituting cowpeas or soy beans. Seed from fields known tobe infested should, of course, be avoided.

No insects are known to affect crimson clover seriously, nor areweeds of great importance in clover planted on clean fields. Whenplanted in cultivated crops or in poorly prepared ground crimsonclover is often seriously damaged by a rank growth of chickweed,knawel (moss weed), winter cress, and other winter-growing annuals.

WASHINGTON : GOVERNMENT PRINTING OFFICE : 1920

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