Clovers and How to Grow Them

by Thomas Shaw

Preparing the Soil.—In preparing the soil for alfalfa the aim should be to make a seed-bed clean, rich, fine, moist, even, and sufficiently firm or friable, according to the conditions. The subsoil should also be made sufficiently dry and open. From what has just been said, it will be apparent that in properly preparing the seed-bed, it will be necessary to study closely the requisite conditions.

The advantage from having a clean seed-bed will be apparent when it is called to mind that alfalfa is a somewhat delicate plant when young, and that because of this, it is ill able to overcome in the fight with weeds. Cleanness in the surface soil may be obtained by summerfallowing the land, by growing a root crop or a crop of corn or any of the non-saccharine sorghums. When the seed is spring sown, this preparation must be given the year previously, but when autumn sown, it may be given the same season. In preparing the land thus, the aim should be to make the surface as clean as possible, rather than to get weed seeds out of the lower strata of the cultivated soil, in which they will likely perish before the field sown to alfalfa is broken up again. Summerfallowing makes an excellent preparation for the land, because of the fine opportunity which it furnishes for cleaning the same perfectly and leveling it off properly. The excellent condition in which it puts the seed-bed, viewed from the standpoint of the duration of the years of cropping that are likely to follow, would seem to more than justify such preparation of the land. The outcome may more than justify the loss of the crop for one season when thus summerfallowing the land. But it may not be necessary to lose the production of one season whether the seed is sown spring or autumn, as the summerfallowing in the North may follow the pasturing off of some crop, and in the South the interval for fallowing the land may be sufficiently long after the harvesting of an early winter grain crop, before sowing the seed in the autumn. (See [page 136].)

When sowing the seed autumn or spring, on land that is filled with weed seeds near the surface, it is frequently better to defer sowing the seed for some weeks to give time for sprouting many of these than to sow at once. This suggestion is specially applicable to spring sowing. It should also be mentioned that when the weeds infesting the soil are annual or even biennial in character, the harm done to the alfalfa by these will be much less than when the land is infested with perennials at the time of sowing. The former may be prevented from seeding by clipping back frequently, while the latter remain in the soil, increase from year to year, and injure the plants by crowding. Where crab grass grows abundantly, as in some parts of the South, unless the alfalfa is sown and cultivated, spring sowing ought to be avoided. But it is less objectionable to sow alfalfa on land that is weedy when the adaptation of the land for the crop is high than when it is low, as the alfalfa in the former instance has so much more power to fight its own battle. On good alfalfa soils, therefore, it may be wiser in some instances to sow alfalfa in weed-infested land than to defer sowing for a whole year in order to clean the land.

It is greatly important that the land shall be rich in available plant food on which the seed is sown. If naturally poor, it should be well fertilized before sowing. When this cannot be done, it is better not to sow. A vast preponderance of the land in the Rocky Mountain region, when first broken, would seem to possess abundantly all the essential foods required by alfalfa; hence, for a time, at least, it is not necessary to enrich these before sowing the seed. The sandy and hungry gravelly soils, which are considerable in the South, in the Atlantic States, and in some of the Central and Northern States, should be fertilized before laying them down to alfalfa. Such fertilization usually calls for both humus and readily available plant food, and these are most cheaply supplied by growing certain green crops and plowing them under, or by applying farmyard manure. These may be supplemented when necessary by commercial fertilizers. Some precede alfalfa on such soils by growing cow peas or soy beans, followed by crimson clover, both crops being plowed in, and shortly before sowing the alfalfa they apply more or less of phosphoric acid and potash, which is usually incorporated in the surface soil by the harrow. On some soils, as in some parts of Florida, two successive crops of cow peas should be plowed under before sowing alfalfa. When farmyard manure can be used in fertilizing those leechy soils it is well when it can be applied on the surface in a somewhat decomposed form and also kept near the surface during the subsequent cultivation given when preparing the seed-bed. In the North it is best applied in the autumn or winter, and in the South in the summer. But on loam soils with a reasonably retentive subsoil, the better way to apply farmyard manure is to make a heavy application of the same to the crop preceding the alfalfa. It has thus become incorporated with the soil, and many weed seeds in it will have sprouted before sowing the alfalfa. The results from applying manure on soil somewhat stiff and not highly productive have been noticeably marked. This may have been owing in part to the mechanical influence of the manure on the land. The relation between the free application of farmyard manure and abundant growth in alfalfa is so marked in all, or nearly all, soils west of the Mississippi River that in many instances better crops will be obtained from poor soils well manured than from good soils unmanured. The relation between abundant manuring and soil inoculation is worthy of more careful study, in the judgment of the author, than has yet been accorded to it.

Fine pulverization of the surface soil is advantageous when sowing alfalfa, because of the influence which it has upon the retention of moisture near the surface, and upon the exclusion from the soil of an overabundance of light. It is in clay soils, of course, that this condition is most difficult to secure. The agencies in securing it are the cultivator, the harrow and the roller, and in many instances the influences of weather, after the land has been plowed, especially when plowed in the autumn prior to spring seeding.

Moistness in the seed-bed sufficient to promptly sprout the seed is a prime essential, but it is very much more important where the seasons are dry than where the lack of rain is but little feared. When the seed is sown after summerfallow or cultivated crops, it is usually considered preferable to make the seed-bed without using the plow, but to this there may be some exceptions. If sowing is deferred for a few weeks in the spring on such lands, or on other lands autumn plowed or early spring plowed, a free use of the harrow ought to be made in the interval, because of the favorable influence which this will have on the retention of moisture. In preparing some soils for autumn sowing after a grain crop, as in some parts of Nebraska and Kansas, it is only necessary to use the harrow; in preparing others the disk and harrow; and in yet others the disk and harrow and roller. In preparing other soils, as the clays of the South, it may be necessary first to plow and subsoil, and subsequently to use sufficiently the harrow and roller.

Evenness in the soil on the surface is important when it is so retentive that water may collect in the depressions after heavy rain. In such places the plants are much liable to fail, especially in the early winter, or even shortly after they may have begun to grow, if moisture is excessive. In order to smooth and even the land sufficiently, it may be necessary to run over it some form of leveller. This does not mean, however, that it will not be necessary sometimes to plow the land in ridges, or "lands," as they are sometimes called, but it does mean that the slope from the center of the lands toward the furrows shall be even and gradual, in order that an excess of surface water, as in rainy climates, shall be carried away by the latter.

Firmness in the seed-bed is necessary chiefly to prevent too much drying out near the surface in dry weather, and the holding of too much water in the spaces between the particles near the surface in wet weather, followed by freezing of the soil. The less deep the stirring of the cultivated portion when preparing it, the longer the interval between such stirring and the sowing of the seed, and the heavier the pressure when rolling, the more firm will the seed-bed be. The deeper the land is plowed, therefore, the longer should be the interval before it is sowed, but ample rainfall will shorten this period. Firmness in the seed-bed is more important, relatively, in summer or early autumn when evaporation from the surface soil is the most rapid. On some soils of the Middle States which border on the Mississippi, the early sown autumn crop will sometimes perish after the plants have grown some distance above the ground, because of want of firmness in the soil; hence, in such locations harrowing the surface of the ground thoroughly may sometimes be a more suitable preparation than plowing and harrowing.

Friability in the seed-bed is important when the soils are heavy. The influences which promote it are the presence of humus, liberal cultivation, and sometimes weather influences, as rain and frost. Unless heavy clay soils are brought into this condition, the roots of the alfalfa will not be able to penetrate the soil quickly enough or deeply enough in search of food.

As has been intimated, it will not avail to sow alfalfa in soils not sufficiently drained naturally or otherwise. Usually, good alfalfa soils have sufficient drainage naturally, the subsoil being sufficiently open to admit of the percolation of water down into the subsoil with sufficient quickness. But good crops of alfalfa may be grown on subsoils so retentive that underdrainage is necessary to facilitate the escape of an excess of moisture with sufficient quickness. The question has been raised as to whether the roots of the plants will be much liable to enter and choke the drains at the joints between the tiles. While it would not be safe to say that this would never happen, it is not likely to happen, owing to the character of the root growth. Where too much water is held near the surface, in climates characterized by alternate freezing and thawing in winter, the young plants will certainly be thrown out through the heaving of the soil.