Botanical Description

8/4/2019 Botanical Description

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Botanical description:

Alfalfa is a strongly perennial plant which is able to live thirtyyears or more under favourable conditions. It has a typicaltaproot; that is, the root system consists of a strong main rootfrom which secondary side roots branch off. As there are norunners or creeping roots, all the overground branches start fromthe uppermost part of the taproot which generally protrudes abovethe ground and is known as the crown. With increasing age, thecrown is apt to split into two or more branches, the upper ends ofwhich are free and form a kind of tuft, sometimes of considerablecircumference.

The main root, which when old is an inch or so thick and ratherwoody, finds its way down to a considerable depth if the soilpermits. On the roots are found the nodules, typical of theleguminous plants. They are on the finer branches and areclustered together into irregular bunches. The stems, which in oldplants are exceedingly numerous, are generally from two to threefeet high at flowering time. As a rule, they are little branched,especially when the stand is dense. They are round below, more

or less angular towards the top, and usually smooth.

The leaves, which are alternate (that is, solitary at each joint andscattered along the stem), consist of three leaflets like those ofRed Clover. The leaflets are rather narrow, two to three times aslong as broad, and sharply toothed in their upper part. The middleone has a short stalk whereas in the cultivated species ofTrifolium the central leaflet has no stalk. Occasionally leaves withfour or five leaflets are found but not so often as in Red Clover.Biology of flower:The flowers are in a short and somewhat one-sided cluster. Eachcluster contains from ten to twenty purple flowers of the ordinaryleguminous shape, as described on page 15. They are fertilizedby means of insects, especially certain kinds of bees. In all


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leguminous plants fertilized in this way, the stamens may comeinto close contact with the body of the insect. A bumble bee, forinstance, visits Alfalfa. The nectar being in the bottom of theflower, it has to poke its proboscis down to the bottom of the

flower tube. When it comes in contact with the lower part of theblossom, it works like a touch on the trigger of a gun. The clusterof stamens is set like a spring, and the touch throws the upperpart of stamens and pistil forward with a jerk. An insect sitting onthe flower will thus be hit and his body powdered with pollen.When visiting another flower the same thing happens; the pistilcomes in contact with the pollen on the body of the insect. Thepistil is thus fertilized and more pollen is deposited on the insect.

It is evident that cross-fertilization must frequently occur. As aninsect will probably visit many flowers of a plant and travel fromone plant to another, an individual may be fertilized by its ownpollen as well as by pollen from another.

Whether self- or cross-fertilization is most beneficial has,however, not yet been proved. Should a flower not be visited byany insect strong enough to open it, it will not be fertilized, notbeing able to explode by itself. The production of seed thusdepends largely upon insects. The weather is also a factor, theflowers being almost insensible in cold, rainy weather, whereas insunshine they will promptly respond to the slightest irritation. Incommon Red Clover the stamens and pistil gradually resume theiroriginal positions; as their elasticity is not affected by one or twovisits, there is always a chance for proper fertilization. In Alfalfathere is no second chance; if an insect's first visit has no effect,the flower will not produce seed. After the pollen has been

discharged, the pistil does not turn back to its original position; itstop remains firmly appressed to the standard of the flower. Ittherefore develops into a curved fruit, although it is perfectlystraight so long as it is enclosed within the flower. Its bending,which starts with the explosion of the flower, increases with its


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growth, and when the fruit is ripe it has the shape of a twistedshell.Geographical distribution and history:The home of Alfalfa is Asia, probably the southwestern parts. Ithas been grown in Persia from time immemorial and is perhapsthe oldest forage plant in the world. It was highly esteemed asfodder for horses, its Persian name meaning horse fodder. FromPersia it was brought to Greece about 500 B.C., whence it spreadto Italy. It was introduced to western Europe by way of northernAfrica. The Arabs carried the plant to Spain in the seventhcentury. From Spain it was introduced into France. It is now

grown in all European countries except the most northern. It wasintroduced by the Spaniards into Mexico, whence it spread to thewestern United States and to South America, and by the Englishand other colonists to the eastern parts of North America. It isnow cultivated all over the United States. In Canada it is confinedto small areas, southern Ontario and southern Alberta being thetwo districts where it is grown extensively.Origin of name:Alfalfa is a Spanish version of the Arabian " Alfacfacah" whichmeans "The best sort of fodder." Some have thought it to bederived from the Arabian "Al-chelfa," which means "That whichgrows after something else," and is generally applied to plantswhich thrive after the spring growth has disappeared. The lattername would signify the ability of the plant to grow during the hotsummer and perhaps refer to its power of producing many cropsduring the season. The first-mentioned derivation, however, is

probably the correct one, the Spanish "Alfalfa" having beenidentified with the Arabian "Alfacfacah" in the 15th century by FrayPedro de Alcala, a prominent specialist on the Arabian language.

In Europe Alfalfa is always called Lucerne. The origin of this wordis uncertain. It has nothing to do with the Swiss state as the name


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was used before the plant was known in Switzerland. It is notlikely that it was derived from the Lucerna valley in northern Italy,as is generally assumed by American authors. An old Spanishname for the plant is " Userdas," which is possibly identical with

the name "Louzerdo," used in southern France. More likely thename Lucerne comes from "lucerno," which is an old Provencalword.Varieties:A great many varieties of Alfalfa occur in the trade, some of whichare real botanical varieties; that is, they can be distinguished byfixed botanical characteristics. Turkestan Alfalfa, for instance, has

short, round leaflets and dull seeds. Others are only geographicalvarieties; their names merely signify that the seed has beengrown in a certain country. Several, however, show decidedlypractical qualities, such as hardiness, resistance to drought anddisease, stooling power, seed production, etc. For Canada onlyhardy varieties are of importance. Arabian or Peruvian Alfalfa, forinstance, will be winter-killed, and, generally speaking, varieties ofa southern origin will suffer. When buying seed the farmer shouldtherefore make sure that the variety offered him is suitable for the

climate. It is always advisable to choose a variety grown in acountry with a climate similar to that where the plant is to begrown.Cultural Conditions:The proper development of Alfalfa largely depends on the soil. Itcan be grown on many kinds, from sand or sandy loams to heavyclays. It thrives best in deep loams with open porous subsoil

where the taproots are not hindered. Asthe roots penetrate to a considerable depth, the quality of thesubsoil is of great importance. If it is compact and impenetrable itwill be a serious obstacle to successful Alfalfa growing. For thesame reason, there is little chance of a good stand on shallow soilon rock unless the roots can find their way through cracks. Alfalfa


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will stand a certain amount of alkali in the ground, but it should beleached out from the surface before the seed is sown, andafterwards should be kept from five to six feet below by irrigation.Acidity has always a detrimental influence. Where the soil is sour,

an application of lime will prove beneficial.Climate:As the roots go deep, Alfalfa, although dwarfed in growth, is notseriously affected by severe drought. It likes a reasonable amountof moisture but is sensitive to an excess. If the subsoil isimpervious, so that after a heavy rain the surface water cannotdrain off rapidly, the accumulation will prove disastrous or will at

least reduce the vitality of the plants. The soil must therefore bekept well drained, especially in early spring. In poorly drainedfields, Alfalfa will be injured and sometimes killed in the low spotswhere water has accumulated. An excess of water in the groundwill at least keep the plants back and prevent them from makingan early start. Where the drainage is poor, alternate freezing andthawing does more harm than in well drained land as the heavingof the soil injures the root system. The strain is often so great thatthe taproot is ruptured and the plant dies.Inoculation:Like other leguminous plants, Alfalfa depends for its vigorousdevelopment on the bacteria in the nodules of the roots, which areclosely related to, or perhaps identical with, those on SweetClover; it thrives well on soil where Sweet Clover has been grown.Habits of growth:Alfalfa is generally sown in the spring. The young plants aredelicate and succeed best where there is no competition. Theland should therefore be as free as possible from weed seeds. Asthe plants are rather tender the first year, they should be givenevery chance to become as strong as possible to withstand thewinter. It is therefore not advisable to cut or pasture Alfalfa the


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first season. During the second and following years the growthstarts early and continues until late in the fall, new branchesdeveloping from the crown of the root. Under favourableconditions Alfalfa reaches a great age and gives large returns.Agricultural value:The feeding value of Alfalfa was recognized in Persia long beforethe Christian era and it was highly esteemed by the Arabians. Atpresent no fodder plant is known which can compete with it innutritive value and general importance for feeding. It is relished byall kinds of stock, horses, cattle, sheep and hogs eating it witheagerness. Even Red Clover is inferior to it in nutritive value, the

protein content being greater in Alfalfa. It can be fed to greatestadvantage to dairy cattle but is also important for fattening allkinds of farm animals, especially sheep and hogs.Fodder:Farmers sometimes say that Alfalfa does not make good hay, butsuch statements are usually the result of cutting at the wrongtime. Its value for hay depends upon its nutritive value and itspower of producing a number of crops in the season. As with

most forage plants, the quality rapidly deteriorates after the plantshave begun to blossom. The stems then lose their succulence,be-come hard and woody, and the leaves are apt to fall off. Whenthe plants begin to form their blossoms, new secondary stems aredeveloped from buds at the crown. As it is upon this secondarygrowth that the second cutting depends, the first cutting must bedone before the secondary stems have grown tall enough to becut off by the mower. For this reason it is advisable to cut a little

earlier than the nutritive value and yield of the hay demand.

If it is cut at the beginning of the flowering period, the yield of thefirst crop will be a little lessened, but the second growth willdevelop more quickly and the return will be greater. Early cuttinggives a greater total crop of better hay than late cutting. Where


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the season is long and the weather favourable, five or six cuttingsa year can be secured. In northern countries such as Canada, twoor three cuttings a year may be expected. In irrigated districts orin places where haymaking time is dry, it is not difficult to cure

Alfalfa into bright green hay of excellent quality. Where rains orheavy dews are frequent after cutting, the hay is apt to turn yellowor brown. Its nutritive value is considerably lessened and itspalatability lost. Curing is generally done in the same way as forRed Clover. Alfalfa should, however, be handled more carefully,as the leaves easily fall off and their shattering causes aconsiderable loss of fodder.Pasture:When Alfalfa is grown for pasture, which is only done to a limitedextent in Canada, it is important to get the plants well establishedbefore turning the stock into the field. It is never advisable topasture Alfalfa before the third year. Even in old fields care mustbe taken to prevent the plants being killed in spots. Alfalfa has asingle taproot, the crown of which generally stands a little aboveground. Being thus exposed, it might easily be injured bytramping, especially when the ground is soft from heavy rains. As

the new stems come from the crown, Alfalfa is liable to beseriously damaged by close pasturing with sheep. It is notadvisable to pasture late in the fall, as that would leave the crownexposed and apt to be winter-killed.

Like Red Clover, Alfalfa when pastured may cause bloating,especially in cattle and sheep, if the animals do not becomeaccustomed to it gradually. The danger is especially great on wet

days or when the plants are moist with dew. It is highly esteemedas a pasture for hogs. If the field is divided into two or three partsand pastured in rotation, Alfalfa is given a chance to recover anda large number of hogs can be fed without injury to the field.Sowing for hay or pasture:


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Alfalfa can be sown with or without a nurse crop, according to the

climate and the soil. In Ontario barley is generally used. Tests at

the experimental farm at Indian Head, Sask., show that in the

Prairie Provinces it is advisable to sow without any nurse crop,thus giving the plants the benefit of all the moisture in the ground.

The amount of seed to be sown depends upon its quality and the

soil, twenty to twenty-five pounds to the acre being considered a

reasonable amount. Good stands are obtained by using a smaller

amount of seed, but thick sowing will produce hay and pasture of

finer quality.

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Botanical Description