Since sweet clover is seldom sown for the purpose of providing food for live stock, it is not sown in mixtures, nor is it well adapted for being sown thus, because of the large and luxuriant character of the growth, which would tend to smother other plants sown along with it.
The amount of seed to sow has been variously stated at from 15 to 20 pounds per acre. The smaller amount should be enough for almost any purpose, and a much smaller amount should suffice for sowing in byplaces and along road sides, where the plants retain possession of the ground through self-seeding.
Pasturing.—Because of the bitter aromatic principle which it contains, known as commarin, stock dislike it, especially at the first. And it is questionable if they can be educated to like it in areas where other food, which is more palatable, grows abundantly. In an experiment directed by the author at the Minnesota University Experiment Station, sheep pastured upon it, and did not take kindly to it; but by turning them in to graze upon it in the morning, they cropped it down. In localities where good grazing is not plentiful, if live stock have access to it, especially when the plants are young, they will so crop it down that in a few years it will entirely disappear. But where other pastures are abundant, it will continue to grow indefinitely. It would not seem wise to sow it for the purpose of providing grazing, unless where the conditions for growing other and better grazing are unfavorable.
Some have spoken favorably of sweet clover for soiling uses. It makes a very rapid growth quite early in the season, and when cut and wilted more or less before being fed, the palatability is thereby considerably increased. Small plots of this plant near the outbuildings may in this way be utilized with some advantage in the absence of better soiling plants.
Harvesting for Hay.—Sweet clover is not a really good hay plant under any conditions, and if not cut until it becomes woody, is practically valueless for hay. It ought to be cut for hay a little before the stage of bloom. If cutting is longer deferred, the plants become woody. Such early cutting, however, adds much to the difficulty of curing the crop, since, while naturally succulent, its succulence is then, of course, considerably more than at a later period. It should be cured like medium red clover. (See [page 96].) If not cut sufficiently early, and cured with as much care as is exercised in curing alfalfa, there will be considerable loss from the shedding of the leaves.
More commonly the plants are not cut for hay the year that they are sown, but some seasons such harvesting is entirely practicable in certain situations. The hay crop or crops are usually taken the second year. Sometimes the crop is cut twice. It is entirely practicable to obtain two cuttings under ordinary conditions, because of the vigor in the growth, and because of the early season at which it must be harvested for hay. From 3 to 4 or 5 tons may thus be obtained in many instances from the two cuttings.
Securing Seed.—Nearly all of the seed sown in this country is imported. The author has not been able to obtain information with reference to growing seed within the United States; hence, the inference is fair that but little of it has been grown for that purpose up to the present time. Since, however, it seeds freely, and since the price of seed is high, seed crops, more especially when the plants are also utilized as bee pasture, ought to prove remunerative in the hands of judicious growers.
The seed crop is obtained usually, if not always, the second year after the sowing. If cut for hay before coming into bloom, it will grow up again and bear seed profusely. This would seem preferable on strong soils, as it would prevent that rankness in growth which would militate against abundant seed production, and which would add much to the labor of handling the crop.
The seed crop may be cut and handled in substantially the same way as medium red clover when grown for seed. It may also be cured and thrashed essentially in the same way. (See [page 105].) The author has not been able to obtain information with reference to the average yield of the seed crop under American conditions. The seed, like that of the medium red variety, should weigh 60 pounds per bushel.
Renewing.—In the sense of a pasture or hay crop, it would not seem necessary to try to renew this crop, because of the relatively low value which it possesses for these uses. When grown for bee pasture, it will renew itself for an indefinite period when the plants are not cut for seed and where the conditions are favorable to growth. When grown to keep soils from washing or railroad embankments from breaking down, it will, of course, renew itself in the same way. In time, however, it is usually superseded by some kind of grass, for which it has prepared the way by the ameliorating and renewing influence which it exerts upon the soil.