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of more or less attention on the part of the husbandmen in the various parts of this continent.
Chapter XII. is devoted to a brief discussion of miscellaneous varieties which have as yet been but little grown in this country, or of varieties of but local interest. The former are Sainfoin (Onobrychis sativa), Egyptian clover (Trifolium Alexandrianum), yellow clover (Medicago lupulina), Sand Lucerne (Medicago media), and a newly introduced variety of Japanese clover (Lespedeza bicolor). These may prove more or less valuable to the agriculture of the United States when they have been duly tested, a work which as yet has been done only in the most limited way. The latter include Florida clover (Desmodium tortuosum), more frequently called Beggar Weed, Buffalo clover (Trifolium reflexum), and Seaside clover (Trifolium invulneratum). These may be worthy of some attention in limited areas where the conditions are favorable, but it is not likely that they will ever be very generally grown. They are dwelt upon rather to show their small economic importance and with a view to prevent needless experimentation with plants possessed of so little real merit.
SOME GENERAL PRINCIPLES WHICH APPLY TO THE
GROWING OF CLOVERS
In growing clovers, as in growing other crops of the same species, which embrace several varieties, certain features of management will apply more or less to all of these in common. It will be the aim to point out the chief of these in the present chapter.
Adaptation in Clovers.-Adaptation in the varieties of clover considered will be more fully given when discussing these individually, but enough will be said here to facilitate comparisons. Clover in one or the other of its varieties can be grown in almost all parts of the United States and Canada. Speaking in a general way, the medium and mammoth varieties can be grown at their best between parallels 37o and 49° north latitude. Alfalfa has special adaptation for mountain valleys of the entire West, but it will also grow in good form in parts of all, or nearly all, the other States. Alsike clover grows in about the same areas as the common and mammoth varieties, but it may also be grown further North, owing to its greater hardihood. Crimson clover has highest adaptation to the States east of the Alleghany Mountains and west of the Cascades, but will also grow in the more Central States south, in which moisture is abundant. Small white clover will grow
in any part of the United States or Canada in which moisture is sufficiently present. Japan and burr clover grow best south of parallel 37° and east of longitude 98°. Sweet clover will grow in all the States and provinces of the United States and Canada, but has highest adaptation for the Central and Southern States.
With reference to adaptation to soils, medium and mammoth clover grow best on upland clay loam soils, such as have sustained a growth of hardwood timber, and on the volcanic ash soils of the Western mountain valley. Alfalfa flourishes best on those mountain valley soils when irrigated, or when these are so underlaid with water as to furnish the plants with moisture. Alsike clover has much the same adaptation to soils as the medium and mammoth varieties, but will grow better than these on lowlying soils well stored with humus. Crimson clover has highest adaptation for sandy loam soils into which the roots can penetrate easily. Small, white clover has adaptation for soils very similar to that of alsike clover. Japan clover and burr clover will grow on almost any kind of soil, but on good soils the growth will, of course, be much more vigorous than on poor soils. Sweet clover seems to grow about equally well on sandy loams and clay loams, but it has also much power to grow in stiff clays and even in infertile sands.
Place in the Rotation.—All the varieties of clover discussed in this volume may be grown in certain rotations. Their adaptation for this use, however, differs much. This increases as the natu
ral period of the life of the plant lessens and vice versa. Consequently, the medium red variety, the mammoth, the crimson, the Japan and the burr varieties stand high in such adaptation. The alsike, living longer, is lower in its adaptation, and alfalfa, because of its long life, stands lowest in this respect. The small, white variety is almost invariably grown or found growing spontaneously along with grasses, hence no definite place has been or can be assigned to it in the rotation. Sweet clover being regarded by many as a weed has not had any place assigned to it in a regular rotation, although in certain localities it may yet be grown for purposes of soil renovation. (See page 306.)
All these crops are leguminous without any exception. This fact is of great significance where crops can be rotated. They have power to gather nitrogen from the air and store it in the soil in tubercles which form on their roots, in all soils in which they produce a vigorous growth. This fact indicates where they should come in the rotation. They should be grown with a view to gather food for other crops made to follow them, which have not the same power. They should, therefore, be made to precede such crops as the small cereals, corn, the sorghums, the millets and cotton. But since these clover plants have the power to bring nitrogen from the air, it must not be supposed that they will grow with sufficient vigor in soils destitute of this element. They must be able to appropriate enough from the seed soil to give them a good start before they can draw nitrogen from the air, hence, though they may, be made to follow almost any kind of crop, it may sometimes be necessary to apply some nitrogenous fertilizer before they will make a vigorous growth.
The clovers, unless in the case of some of the smaller varieties, are more commonly sown to provide hay than pasture in the first crops obtained from them. The value of the hay is increased or lessened in proportion as weeds are present. To insure cleanliness in the hay crop, therefore, the system which aims to sow clover seed on land to which clean cultivation has been given while growing on them a cultivated crop, as corn or field roots, meets with much favor. The mechanical condition of the soil immediately after growing these crops also favors the vigorous growth of the young clover plants, more especially when they are sown upon the surface of the land after some form of surface cultivation, rather than upon a surface made by plowing the land after cultivation has been given to it, but to this there may be some exceptions.
Clover in some of its varieties is frequently grown from year to year in orchards and for the two-fold purpose of gathering food for the trees and providing for them a cover crop in winter. The medium red and crimson varieties are preferred for such a use. The latter is the more suitable of the two, since it does not draw on soil moisture needed by the trees, owing to the season at which it is grown. Enough of the seed of these crops may be allowed to mature to re-seed the land from year to year, and thus keep it producing. The clover plants