Part 2

=VARIETIES.=

Crimson clover is exceedingly variable both in color of flower and in time of maturity. These variations are particularly noticeable in fields planted from a mixed lot of seed, the flowers presenting a range in color from nearly pure white to a deep purplish red and the seeds a difference in date of ripening of more than a month. Since crimson clover is thought to be mainly self-pollinated, it is easy to fix these qualities by selection and to establish definite varieties.

In Europe six or seven different varieties of crimson clover are recognized and sold by seedsmen, varying from extra early crimson flowered to, extra late white flowered and from very hardy to non-hardy. By the use of a succession of these varieties the European farmer is able to spread his harvest over six or seven weeks instead of having it concentrated within a few days, as in America. Similarly, the culture of the plant has been extended northward from Italy to Sweden by means of hardy strains. A wild form of crimson clover having yellowish flowers and hairy foliage occurs in southern and eastern Europe and in England, but it is not of economic value.

In America no sharply defined varieties of crimson clover are recognized, except a white-blooming variety which is sold in the South and is two weeks later than the ordinary crimson-flowered sort. Hardy strains have been developed and used in a small way in Massachusetts and Ohio, but these are not commercially available.

=USE IN THE ROTATION.=

=SEEDING IN INTERTILLED CROPS.=

In former years a large percentage of the crimson-clover acreage was seeded in corn or other intertilled crops at or shortly after the time of the last cultivation. In most of the crimson-clover area it is possible to make such a seeding, obtain a good growth during the fall and early spring, and mow or plow under the clover in time, for breaking up the land for another crop of corn. This has been the standard method of growing this clover, and it is still the leading practice in many of the older sections. Corn in the summer with crimson clover in the winter is a cheap and convenient method of growing a cash crop and a restorative crop the same year, and the reputation of crimson clover as a crop increaser is largely based on this simple rotation. Instances are by no means rare where the yield of corn has been gradually increased from 10 bushels per acre to as high as 70 bushels by this means.

The difficulty with this method is the possibility of the stand of young clover failing through drought. The growing corn makes a heavy demand on the soil moisture, and if there is not enough moisture for both clover and corn the latter gets the larger share and the tender clover plants are likely to succumb. Because of the risk involved, farmers in the upland sections are seeking other and more reliable methods of seeding, and the sowing of crimson clover in corn is gradually decreasing.

Where the danger from fall drought is not serious, crimson clover may be sown in corn at the time of the last cultivation or when the corn leaves have just begun to wither. South of central Virginia there is likely to be much hot weather after the corn is laid by, in which case it is best to delay the seeding of the clover until after the first rain. The appearance of a field of crimson clover seeded in corn the previous summer is shown in figure 3.

South of southern Virginia crimson clover can be seeded in cotton, provided the field is free from crab-grass and other weeds and the soil is not too dry. In the extreme north of the cotton belt the seed may be sown at the last working of the cotton; farther south this occurs too early and it is necessary to wait for a rain, which often comes at about the time of the first picking.

Crimson clover may be seeded in practically any of the cultivated truck crops which receive their last cultivation from 8 to 12 weeks before the first frost. It is not practicable to seed the clover in late potatoes, sweet potatoes, or other root crops, as the digging in the fall practically destroys the clover.

Ordinarily, crimson clover does not succeed when sown in cowpeas, sorghum, or watermelons, owing to the heavy shade cast by these crops. It can, however, be seeded in tobacco, tomatoes, cultivated soy beans, and cantaloupes.

=SEEDING AFTER AN EARLY-MATURING CROP.=

Seeding crimson clover in an intertilled crop is successful mostly on sandy soils, which can easily be prepared for seeding even in mid-summer. On clay soils and in weedy fields this method of seeding is likely to be unsatisfactory. Such soils are usually hard and dry in August and can with difficulty be brought into condition for a seed bed, with the result that a large percentage of such seedings fail. A better plan on clay soils, and on sandy soils in many cases, is to seed the crimson clover on specially prepared ground from which all other crops have been removed. Such ground can be made as fine and firm as desired. Furthermore, the clover after planting does not have to compete with another crop for the soil moisture. This method is somewhat more troublesome than planting in intertilled crops, but the greater certainty of getting a stand more than offsets the greater cost. Planting crimson clover on specially prepared ground has extended the culture of the plant to regions where it was not hitherto grown and is increasing the reliability of the crop in sections where it has been long established.

In the ordinary rotation, crimson clover follows a crop of small grain. However, it may follow any crop that is removed 8 to 10 weeks before frost, or it may be seeded on fallow ground. Ground from which early potatoes have been removed is especially favorable for the establishment of a stand of this clover. The residual effect of the fertilizers used on potatoes is partially responsible for this, while the well-settled seed bed, which requires only leveling and harrowing, also presents favorable conditions for the crimson-clover seedlings.

In many parts of the South crimson clover can be seeded in corn stubble if an early variety of corn has been used. Although there is some risk that the clover may not make enough growth before winter if seeding is delayed until the corn is harvested, the danger of losing the stand is not as great as if the clover were seeded earlier, while the corn was standing.

Crimson clover is sometimes seeded after a grass or clover crop if the rainfall in July is sufficient to cause the sod to decay. In the far South it can be planted after peanuts, while in all sections it can be sown as a catch crop on land where cotton or other crops have died early in the season.

=REQUIREMENTS FOR OBTAINING A STAND.=

Probably the difficulty most commonly experienced in growing crimson clover is failure to obtain a satisfactory stand. Sometimes the seed does not germinate well; more commonly good germination is secured, but the seedlings wither and die before they can become established. Frequently not more than 50 per cent of the plants survive the first three weeks, while a complete failure of the crop is a common risk even in the sections where crimson clover is most widely grown.

The most common cause of failure to obtain a stand is hot, dry weather after planting. The seedlings of crimson clover are tender, succulent, and shallow rooted and are easily killed by lack of moisture. Unfortunately, in most of the crimson-clover area the weather during late August and early September is very likely to be hot and droughty, making the planting of the clover at that time rather hazardous. Some farmers attempt to avoid this difficulty by planting either in early summer or in October, after the fall rains; there is danger, however, that the plants will make too much or too little growth to survive the winter. In the long run it is probably better to plant at the regular time and depend upon thorough preparation of the seed bed to offset any deficiency in the rainfall.

=SOILS.=

Crimson clover can be grown successfully on almost any type of soil if it is reasonably rich, well drained, and supplied with organic matter and the proper inoculating bacteria. Probably two-thirds of the crimson-clover acreage is found on the sandy soils of the Atlantic Coastal Plain, but the crop is not necessarily restricted to sandy soils and is in fact increasing in importance on the red-clay soils of the Piedmont region and in the limestone valleys of Virginia and Tennessee.

Crimson clover has been an important factor in increasing yields on soils that have been abused, but it is not a crop for land which is naturally very poor. It does not do well on rough, newly cleared areas, raw subsoil, Hard, dry clay, or sterile sand. (Fig. 4.) For such soils soy beans, cowpeas, and velvet beans are better suited and should be used for the first three or four years until crimson clover can be successfully grown. Crimson clover can be made to grow on poor soils, provided they are specially prepared by liming, manuring, and inoculating. In general, however, crimson clover is a crop for maintaining soils which are already fairly productive rather than one for inducing productivity in soils where it is quite lacking. If there is any doubt whether the soil is suitable for crimson clover, a small plat should be prepared under field conditions and planted one year for trial.

=PREPARATION OF THE SEED BED.=

To secure a full, even stand of crimson clover with any degree of regularity the seed bed should be well and thoroughly prepared. The soil should be firm, moist, well settled, and fine on top. Only indifferent success can possibly be expected if the seed is scattered on land which is loose, dry, and full of hard lumps and trash. A loose seed bed dries out quickly, heaves during the winter, and on some soils blows and washes badly.

On the other hand, the seed bed should not be too hard, for although this clover often grows successfully on soil which would be too solid for corn, there must be at| least enough loose soil on the surface to cover the seed. Thorough preparation is the very best insurance against failure of the stand through drought or winterkilling, and the most successful growers sow crimson clover on land as well prepared as that for wheat.

To secure a fine, firm seed bed without drying out the surface soil, the land should be prepared with as few operations as possible. A single working when the soil is in a moist, crumbly condition is better than half a dozen workings when the soil is too wet or too dry. In very sandy soils, or soils which do not form a crust, the only preparation needed is to keep down the weeds.

An excellent tool for making the seed bed is the corrugated roller or pulverizer (fig. 5). This implement is an improvement over the old plain roller for breaking clods and is unexcelled for keeping the surface soil moist. It can be used after plowing and again before planting, and even after planting if the soil needs to be compacted. Rolling of some kind to firm the soil is especially important on sandy soils, but it is equally beneficial on clay soils if they are cloddy.