Lucern, or Medicago saliva, L. a valuable exotic plant, which sometimes grows naturally in meadows, pastures, and on ditch-banks; flowers in the months of June and July.- It was introduced from France into Britain, about the middle of the 17 th century. ,

Lucern thrives best m deep, rich, friable loams, whether they abound in sand Or gravel; as well as in all good dry soils, and in the coldest climate. As the luxuriance of its Crops depends entirely on keeping the soil clear from weeds, this circumstance ought to be particularly attended to, while the plant is young. The land ought, therefore, to be previously cleaned; for which purpose Mr. YounG recommends two successive crops of turnips or of carrots, as the most successful mode of preparing it; but, if a fallow be found more convenient, a man should follow the ploughs or harrows while working; collect all roots, weeds, etc.; and clear away such as have taken too deep root, to be eradicated by those implements. The soil must be ploughed and harrowed three times in the second spring, previously to the sowing, in order that it may be perfectly pulverized.—There is no absolute necessity for manure; though, when laid on, it should be spread with the first crop of carrots or turnips.

The land being thus prepared, lucern may be propagated either by sowing it broad-cast; by drilling ; or by transplanting it; all of which methods have been attended with such success, as to render it difficult to decide which is the most advantageous. The proper season for sowing, is towards the end of March, or in the month of April: if broad-cast, 20lbs. of seed will be required for one acre 5 if drilled, lbs. will suffice; provided the seed be set in equi-distant rows of two feet; and, if the lucern be sown with corn, the value of the crop will be considerably increased.-The best grain for this purpose, in Mr. Young's opinion, is oats;6pecks of which should be sown on an acre of very rich land ; but, if the soil be indifferent, two bushels are requisite ; and, if it be poor, three bushels are to be allowed to each acre.—As soon as the oats are sown and harrowed, the lucem should be deposited in the ground, and a light harrow passed over ; a similar method ought to be adopted if the seed be drilled ; but, if sown in a nursery, with a view to transplantation, it should not be mixed with any corn, but committed to the ground early in the spring ; after which the young plants ought to be carefully hand-hoed, to facilitate their growth till the month of August, when they will have attained sufficient size to be removed to the field. This operation is performed by taking up the plants with a sharp spade, during moist weather ; then cutting off the taproots, eight, nine, or ten inches beneath the crown of the plant; though the lateral fibres must be somewhat shortened, and the stalks clipped off about five inches above the crown. After these operations by the knife, the plants are to be thrown into a vessel of water, and placed in the shade, that they may retain their freshness. Holes are next to be made with a dibble, and filled with water, in which the roots are set at the distance of forty inches from each other, the stalks being earthed up to the height of two inches. Should a dry season succeed, it will be requisite to water the plants liberally ; as they will thus not only be invigorated, but the soil will be settled around their roots.—The intermediate spaces ought to be carefully cleared from weeds after every cutting;. and when the plant arrives at perfection, it' will admit of being mowed five and even six times in one season.

Lucern is of great value, and fully merits the commendations bestowed upon its culture. On rich and well-tilled soils, its growth is so rapid, that it rises to the height of eighteen inches within thirty ox forty days; and its produce on poor land is fully adequate to maintain three horses per acre ; though, if the ground be well managed, it will readily support from three to six horses. The expencc of raising this plant is very considerable : Mr. Harte, in his Essays on Husbandry (8vo. 5s. 6d. 2d edit.) estimates it, when transplanted, at 61. 12s. per acre for the first year ; and the cost of the second, as well as each subsequent year, during the continuance of the plant (which may be fixed upon an average at ten years), will amount to about 2l. per acre. If lucern be drilled, Mr. Young computed, in 1796, the expence of the first year to be as follows :

Mr. Young observes, that it is difficult to calculate the expence of mowing, raking, and carting, unless the plantation be sufficiently large to furnish employment for a man, boy, and horse. He is aware of having computed it rather high, though he has not perhaps exaggerated the cost, if the loss of time necessarily attendant on short employ be properly considered. He is therefore inclined to raise the total annual expence to 51.: because he believes that an acre of land cannot be cultivated for a smaller sum, even by very excellent management.

Notwithstanding such heavy ex-pences, the crops of lucern have, in every case, been found adequate to them, so as to answer exceedingly well; and Mr. Young is of opinion, that if the value of the food be estimated by the main ance of cattle per week, it will pay nearly cent per cent.

The first use of this beneficial plant is that of soiling horses in the-stable: for this purpose it is peculiarly advantageous; few other articles of food agreeing so well with those animals. It is likewise eminently adapted to the soiling of working oxen, cows, young cattle, and even hogs, in a farm-yard. In short, Mr. YouNg conceives lucern to be well calculated for fattening oxen, though it has never been tried wiithsuch design. Farther, as hogs do not bite so closely as sheep, he supposes that the former might eat it with safety, and that a small held, planted with It, near the farm-yard, " would be of admirable use and profit."

Beside these various purposes to which lucern is subservient, it ameliorates the soil, so that considerable crops of corn have been obtained after it; nay, instances have occurred, in which a complete ploughing, that was given with a view to eradicate it for corn, has renovated this plant to such a degree, that it was left again for another series of years,—Those of our agricultural readers, who wish to acquire more minute .information relative to the management of lucern, will consult Mr. Harte's classical work above-mentioned, and also Mr. Rocque's Practical Treatise on Cultivating Lucern Grass (8vo. Is. 6d.) in which this interesting subject is fully discussed, while its advantages and expences are fairly appreciated.