Crimson Clover [1938] — Inside the Classic

Emphasis is denoted as _Italics_ and =Bold=.

U.S.DEPARTMENT of AGRICULTURE

By E. A. Hollowell, _senior agronomist, Division of Forage Crops and Diseases, Bureau of Plant Industry_

=Growth and Distribution=

Crimson clover (_Trifolium incarnatum_) is the most important winter annual legume of the central section of the Eastern States (fig. 1). Besides being an excellent hay plant and furnishing an abundance of early spring pasture, it affords protection to the soil during the fall, winter, and spring, prevents soil washing, and provides green manure for soil improvement. This legume has the distinct advantage of being a heavy producer of seed, which can be easily harvested and sown without the use of expensive machinery.

Crimson clover is a native of Europe and is widely grown in France, Hungary, and other central and southern European countries. Seed was introduced into this country as early as 1819, but it was not until 1880 that the plant became of agricultural importance. During the last 6 years the annual commercial consumption of seed in the United States has ranged from 2 to 4 million pounds. In addition, large quantities of home-grown seed are used and handled from farm to farm.

The common name of this clover is derived from the distinctive bright crimson color of the blossoms. Other common names, such as German clover and scarlet clover, are frequently heard in different localities. In general the leaves and stems of crimson clover resemble red clover, but are distinguished by the rounding of the tips of the leaves and a greater covering of hair on both leaves and steins. When it is planted in the fall the leaves develop from the crown and form a rosette, which enlarges whenever weather conditions are favorable. In late spring flower stems develop rapidly and terminate their growth with elongated flower heads. Seed forms and the plant dies with the advent of hot summer weather. The seed is yellow, slightly larger, and more rounding than red clover seed.

Crimson clover is adapted to cool, humid weather and is tolerant of winter conditions where the temperature does not become severe or too variable. In this region (fig. 1) it should be planted in late summer or early fall, since early establishment and growth are favorable to its winter survival. It will thrive on both sandy and clay soils and is tolerant of ordinary soil acidity. On extremely poor soils, stands are difficult to obtain and the growth is stunted. The use of manure and phosphate fertilizers on such soils will improve the chances of obtaining good stands.

Crimson clover may also be successfully grown as a summer annual in Maine, northern Michigan, and Minnesota. The winter culture of this clover may be extended into Kentucky, southern Missouri, and southern Indiana provided the seed is sown in fertile soil early in August. Production may be successfully extended southward with an increase of soil fertility and with seeding delayed until soil-moisture conditions are favorable.

=Seedbed Preparation=

The most important and difficult phase of successful production of crimson clover is getting a stand. Sufficient soil moisture to germinate the seed and to establish the seedlings is the greatest factor in obtaining a stand, which when established usually produces a good crop.

Seedings are usually made in late August or early September between the rows of cultivated crops. Under such conditions an ideal seedbed is difficult to prepare, therefore careful preparation is necessary. Furthermore, the crop plants in the row shade the clover seedlings and seriously compete with them for the available moisture. Increasing the distance between the rows and planting the row crop more thinly will afford better opportunity for the establishment of the clover. When planted between the rows of other crops, the seed is usually broadcast on the surface and covered by cultivating or harrowing (fig. 2). Drilling the seed after the soil surface has been stirred will usually give more complete stands than broadcasting, and it may be done with a small one-horse drill. The seed should not be planted more than one-half to three-fourths of an inch deep, respectively, in clay and sandy soils.

Crimson clover is often seeded following a grain crop, and this is a surer method of establishing a stand than planting between the rows of cultivated crops, providing the seedbed is well prepared. After the grain crop is removed the soil is plowed or disked and allowed to settle. This is followed by light harrowing or disking when necessary to kill weed seedlings. Before the clover is seeded the soil should be firmly packed, because a loose cloddy seedbed is the forerunner of failure. The seed may be either drilled or broadcast, but drilling will give more uniform stands.