On certain soils, as those naturally moist and porous, it may be possible so to renew alsike clover that it will produce hay or pasture crops almost indefinitely, by simply allowing some heads to seed every year and fall to the ground. In meadows, this may be done by not grazing after the hay has been harvested until other heads have formed and ripened. A limited number of these will thus form after the crop has been mown for hay. If the crop has been cut for seed, many heads will in any event be left upon the ground. The same result will follow when grazing the crop, if grazing is made to cease at the right time, and for a period long enough to allow a considerable number of heads to mature. This method of renewal will not prove a complete success on all soils, as, for instance, on those very stiff and very light.
Natural meadows that lie low may be changed in whole or in part into alsike meadows or pastures in some of the States, as has been previously intimated, by sowing seed on them in the early spring. (See [page 202].) In some instances such change has been effected by sowing seed but once, and at the rate of from 3 to 4 pounds per acre. In other instances it has been found preferable to sow a less quantity for two successive seasons, lest one of the two should prove adverse to successful growth in the plants. But on some slough soils a stand cannot be secured by this method of sowing, more especially when they are composed of raw peat.
CHAPTER VI
MAMMOTH CLOVER
Mammoth Clover (Trifolium magnum) was long ago named Trifolium medium by Linnæus. However appropriate the designation may have been at the time, it is not so now, at least under American conditions, as in this country there is no other variety of clover so large, unless sweet clover (Melilotus alba). To apply to it the distinguishing term medium, therefore, is positively misleading, since the smaller variety of red clover commonly grown occupies such middle ground, as the term medium would indicate. Because of this, the author has ventured to designate it Trifolium magnum. It has also been classified, and with no little appropriateness, Trifolium pratense perenne, which has reference to the mildly perennial habit of growth in this plant. In common phrase it is known by such names as Large, Tall, Saplin or Sapling, Giant, Meadow, Perennial Red, Red Perennial Meadow, Pea Vine, Zigzag, Wavy Stemmed, Soiling, and Cow clover or Cow grass. Each of these names has reference to some peculiarity of growth in the plant. For instance, the terms Large, Tall, Saplin and Giant have reference to the size of the plant; and the terms Pea Vine, Zigzag and Wavy Stemmed to the somewhat irregular and trailing habit of growth in the stems, and so of the others. The designation Cow grass is an English term.
Mammoth clover is a large variety of red clover; in fact, the largest variety of red clover in America. The plants are strong, stronger than those of the medium red variety, and the stems are much larger. They are softer than those of the medium red, which to some extent may account for the less erect habit of growth which characterizes it. The leaves are usually destitute of the white spot found on those of the other variety. The heads are also probably larger and somewhat more open, but there is no appreciable difference in the size of the seed. The plants, notwithstanding, bear so much resemblance to those of the common red variety that it is not easy to distinguish them unless by the large size of the plants of the former. The roots are larger and stronger than those of the medium red variety, and as a result have more power to gather plant food in the soil.
Mammoth clover is biennial under some conditions and under others it is perennial, although it is not usually a long-lived perennial. It has a stronger habit of growth than the medium red, and is, therefore, rather better fitted to thrive under adverse conditions, more especially when it has once obtained a hold upon the soil. It grows chiefly in the first half of the season, and makes but little growth, relatively, in the autumn, or, indeed, any time the same season after the crop has been harvested for hay. In the Northern States it comes into flower about the middle of July, and in those of the South correspondingly earlier.
It is relished by all kinds of domestic animals kept upon the farm, but the hay is relatively better adapted to cows and other cattle than to horses and sheep. If cut too late, or much injured in the curing, it is too dusty for horses, and the growth is too coarse to make first-class hay for sheep. It makes excellent soiling food, because of the abundance of the growth and the considerable season during which it may be fed in the green form.
It is peculiarly valuable as a fertilizer and as an improver of soils. In addition to the nitrogen which it draws from the air and deposits in the soil, it brings up plant food from the subsoil and stores it in the leaves and stems, so that when fed it can be returned to the land. It also fills the soil with an abundance of roots and rootlets. These render stiff soils more friable, and sandy soils less porous; they increase the power of all soils to hold moisture, and in their decay yield up a supply of plant food already prepared for the crops that are next grown upon the ground.