greatly interfere with the harvesting of the crops. They are destroyed by giving them poisoned food, trapping, shooting, and suffocating through the use of bisulphide of carbon. Poison is frequently administered by soaking grain in strychnine or dropping it on pieces of potato and putting the same in or near the burrows. Bisulphide of carbon is put upon a rag or other substance, which is put into the burrow and the opening closed.

Dodder is a parasitical plant introduced, probably, in seed from Europe, which feeds upon alfalfa plants, to their destruction. The seeds of alfalfa sometimes become so impregnated with the seeds of dodder that the latter will grow where the seed is sown, thus introducing it to new centers. The dodder starts in the soil and soon throws up its golden-colored thread-like stems, which reach out and fasten on the alfalfa plants that grow sufficiently near. The dodder then loses its hold upon the soil and gets its food entirely from the alfalfa plants, which it ultimately destroys. But since the seeds of the dodder remain at least for a time in the soil, and the adjacent soil becomes infected with them, the circles in which the dodder feeds continually widen. In certain parts of New York State some fields have become so seriously affected as to lead to investigations conducted through officials from the State experiment station. Pending these investigations, the exercise of great care in the purchase of seed and the immediate plowing of the infested areas are recommended.

Some reference has already been made to injuri

ous results from pasturing close in the autumn or winter, except in the most favored alfalfa regions. In addition to what has been already said, the wisdom of not grazing alfalfa the first year is here emphasized, and also the mistake of grazing at any time when the ground is frozen, at least in areas east of and, generally speaking, adjacent to the Mississippi River.

Alfalfa as a Fertilizer.-Alfalfa is not considered equal to medium red clover as a direct means of fertilizing and otherwise improving the land on which it grows. This does not arise from less inherent power on the part of alfalfa to draw nitrogen from the air and deposit it in the soil, but rather from the fact that clover establishes itself more quickly, and is much more frequently grown in the rotation. Several crops of medium red clover can be grown in short rotations, each one being a source of much benefit to the crops that follow, while one crop of alfalfa occupies the land. But when the alfalfa is all fed upon the farm on which it grew, where the plants grow freely, it then becomes a source of fertilization without a rival, probably, among plants grown upon the farm.

The fertility thus furnished does not consist so much in the plant food deposited in the soil directly as in that furnished in the successive crops that are grown and fed every year. In Farmers' Bulletin No. 133, published by the United States Department of Agriculture, it is stated that the Wyoming Experiment Station found 44 pounds of nitrogen, 8.27 pounds of phosphoric acid, and

50.95 pounds of potash in one ton of alfalfa. This would mean that in the yield of alfalfa hay from a given area, estimated at four tons per acre for the season, alfalfa would furnish 176 pounds of nitrogen, 33.08 pounds of phosphoric acid, and 203.8 pounds of potash. If this alfalfa were fed upon the farm, it would not only prove a cheap source of protein for feeding, but it would furnish fertility, as stated above, without seriously diminishing the supply of the same in the surface soil, since much of the fertilizing material produced would come from the air and subsoil. The manure thus made, if carefully saved and applied, would thus add materially to the fertility of the land. If, however, the alfalfa were sold, the mineral matter drawn from the cultivable area of the soil and from the subsoil lying under it would be reduced to the extent of the draft made upon these in growing the alfalfa.

The direct influence of alfalfa upon the fertility of the land on which it grows is shown in the greatly increased production in the crops which follow alfalfa. This increase is not only marked, but it is frequently discernible for several successive years. But as has been intimated, the benefit that would otherwise accrue from growing alfalfa as a direct means of fertilizing the land is much circumscribed by the long term of years for which it is usually grown.

The mechanical effects of alfalfa upon the land are beneficent. It improves the tilth by means of the shade furnished, and the extent to which the

roots fill the soil. These in their decay further influence favorably that friability which is so desirable in soils that are cultivated, and as previously stated, the long, deep roots in their decay exercise a salutary influence on drainage.

The work of breaking alfalfa fields is frequently laborious, owing to the number and size of the roots. If, however, a plow is used, the share of which has a serrated edge, the roots will be cut or broken off more easily and more effectively.

CHAPTER V

ALSIKE CLOVER

Alsike Clover (Trifolium hybridum) takes its name from a parish in the south of Sweden. From there it is probable that it was introduced into England. Linnæus gave it the name of hybridum, imagining it to be a cross between the red and the white varieties. Botanists do not generally hold this view. It is known by various names, as Swedish, White Swedish, Alsace, Hybrid, Perennial Hybrid, Elegant and Pod Clover, but more commonly in America it is spoken of as alsike.

The plants of this variety are more slender than those of the medium red variety, although they grow in some instances to a greater height. The slender stems are much branched. The leaves are numerous and oblong in shape, the flowers are of a pinkish tint, the heads are globular and are about threefourths of an inch in diameter, and the pods, like those in white clover, contain more than one seed. The roots are in no small degree fibrous, and yet the slender tap root goes down to a considerable dis

tance.

Alsike clover is a perennial. In favorable situations it will live for many years. Ordinarily, it grows to the height of 18 to 24 inches, but in slough