Part 1

Transcriber Note

Emphasis is denoted as Italics and =Bold=.

=CRIMSON CLOVER=

LEAFLET No. 160

U.S.DEPARTMENT of AGRICULTURE

Issued June 1938. Revised January 1947

=CRIMSON CLOVER=

By E. A. Hollowell, senior agronomist, Division of Forage Crops and Diseases, Bureau of Plant Industry, Soils, and Agricultural Engineering, Agricultural Research Administration

=Contents=

Page Adaptation 3 Seedbed Preparation 3 Fertilizers 3 Seed Sources and Varieties 4 Dixie Crimson Clover 4 Rate and Time of Seeding 5 Inoculation 5 Unhulled Seed 5 Companion Crops 6 Diseases and Insects 6 Utilization 6 Seed Production 7

CRIMSON clover (Trifolium incarnatum) is the most important winter annual legume of the central section of the Eastern States. This crop can be grown over a much larger area by using seed of adapted varieties for each section, by using better cultural methods, and by fertilizing the soil (fig. 1). Besides being an excellent pasture plant and furnishing plenty of hay, it protects the soil during fall, winter, and spring, prevents soil washing, and provides green manure for soil improvement. This legume has the distinct advantage of producing large quantities of seed that 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 important. The acreage has been steadily increasing. During the 5-year period 1940-45 the annual purchase of seed through markets in the United States has ranged from 6 to 18 million pounds. In 1935 about 2 million pounds were used. In addition, large quantities of home-grown seed are handled from farm to farm.

The common name of this clover is derived from the bright crimson color of the blossoms. Other such common names as German clover and scarlet clover are frequently used. In general the leaves and stems resemble those of red clover, but are distinguished by the rounded tips of the leaves and more hair on both leaves and stems. When crimson clover is planted in fall the leaves develop from the crown and form a rosette, which enlarges whenever weather conditions are favorable. In spring, flower stems develop rapidly and end their growth with long pointed flower heads. Seed forms and the plant dies with the coming of hot summer weather. The seed is yellow and is about twice as large as red clover seed and more rounded.

=Adaptation=

Crimson clover does well in cool, humid weather and is tolerant of winter conditions where the temperature does not become severe or too changeable. It may be planted from midsummer to late fall. In the northern part of the region early seeding and growth are necessary for the seedlings to survive the winter. It will thrive both on sandy and clay soils and is tolerant of ordinary soil acidity. On very poor soils, stands are difficult to obtain and the growth is stunted. The use of phosphate and potash fertilizers and manure on such soils will help to obtain good stands.

Crimson clover may also be grown successfully as a summer annual in northern Maine, Michigan, and Minnesota. Winter culture can be extended into Kentucky, southern Missouri, southern Indiana, and Ohio, provided varieties are grown that are adapted to these sections and the seed is sown in fertile soils early in August.

=Seedbed Preparation=

The most important and difficult part of producing a large crop is getting a stand. Enough soil moisture to sprout the seed and establish the seedlings is the greatest factor in obtaining a stand. When established, common crimson clover usually produces a good crop.

Seedings may be made alone or combined with winter grains, ryegrass, or grass sod. It is possible also to seed between the rows of cultivated crops, but it is difficult to make an ideal seedbed. Furthermore, the crop plants in the row shade the clover seedlings and use some of the available moisture. If the row crop is planted in wider rows and seeded more thinly, the clover will become better established. When planted between the rows of other crops, the seed is usually broadcast on the surface and covered by cultivating or harrowing. Drilling the seed after the soil surface has been stirred usually gives 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. This is a surer method of establishing a stand than planting between the rows of cultivated crops, provided the seedbed is well prepared. After the grain crop is harvested the soil is plowed or disked and allowed to settle. This is followed by light harrowing or disking to kill weed seedlings. Before the clover is seeded the sod should be firmly packed, because a loose cloddy seedbed will not produce good stands. The seed may be either drilled or broadcast, but drilling will give more uniform stands.

=Fertilizers=

Good stands and growth cannot be expected on very poor soils. Soil conditions can be improved by adding phosphate and potash fertilizers and manure or by turning under such crops as cowpeas, soybeans, or lespedeza. In many soils of low fertility the use of a complete fertilizer will encourage early seedling growth and establishment. On fertile sods crimson clover may be successfully grown without fertilizer, but on most sods applications of 200 to 400 pounds per acre of phosphate and 50 to 100 pounds of potash pay in obtaining good stands and vigorous growth (fig. 2).

Frequently a single large application of phosphate and potash fertilizer is sufficient to produce two crops of crimson clover before it becomes necessary to make another application. In some soils the addition of such minor elements as boron may improve growth and increase seed yields. Since the need for minor elements varies from place to place, their use should be based on the recommendations of the agricultural experiment station of the State in which the clover is planted.

=Seed Sources and Varieties=

Before World War II more than half the crimson clover seed used in the United States was imported, principally from Hungary and France. Since 1938 domestic production has rapidly increased, reaching more than 18 million pounds in 1942. Tennessee produced more than half the home supply. Nearly all the crimson clover may be called common crimson clover, since it does not represent strains or varieties having special characteristics. White-flower strains and several others that differ slightly in maturity have been selected but have not been used.

=Dixie Crimson Clover=

Dixie crimson clover is a new hard-seeded variety that has given promising results in extensive trials. It is more widely adapted than common crimson clover, as it grows well in the Gulf coast section and appears to be slightly more winter-hardy than common crimson. Dixie has successfully volunteered to good stands when grown in pastures with Bermuda grass, with small grains for grazing, and in rotation with such cultivated crops as sorghum or late-planted corn.

Seed of Dixie shattered in harvesting operations has successfully produced good volunteer stands in fall. When used in rotations with cultivated crops, the seed must be matured before the seedbed is prepared for the following crop. When Dixie is used in pasture, care should be taken to prevent close grazing at the time of blooming, since it may limit the quantity of seed produced and cause thin fall stands. Summer-growing grasses must be either closely grazed or clipped in fall to give the clover seedlings a chance to become established.

The seed and plants of Dixie cannot be distinguished from common crimson clover, and the variety may be readily contaminated by either cross-pollination or mechanical mixtures. For these reasons the farmer buying Dixie should buy only certified seed.