Crimson clover is a heavy seed-producing plant, and yields of 5 to 10 bushels per acre are common, depending upon the thickness of the stand, the extent of growth produced, and the care used in harvesting the seed. The florets are self-fertile, but bees increase the number of seed per head by tripping and transferring the pollen. Placing colonies of honeybees next to blooming fields will increase pollination. More seed is usually produced on soils of medium fertility than on rich soils, since fertile soils seem to stimulate the growth of stems and leaves rather than develop flower heads.

Large yields and ease of harvesting seed are two important reasons why crimson clover is such an ideal legume crop. Farmers can save seed with very little expense other than their own labor. When the seed heads are mature they readily shatter and are easily harvested either by hand stripping or by using horse-drawn home-made strippers. One bushel of unhulled seed contains about 2 pounds of hulled seed, and although bulky, it can be easily stored on the farm until fall.

When the seed is mature the crop is cut with a mower (fig. 4), which may be equipped with a bunching or windrowing attachment, or it can be harvested with a combine. During wet seasons it is sometimes difficult to combine the seed from standing plants. Under such conditions the plants can be cut and windrowed and than threshed by the combine from the windrow. As crimson clover shatters easily when ripe, cutting with the mower when the heads are damp with dew or rain is recommended. If it is allowed to stand too long after ripening a beating rain will shatter much of the seed. After a few days of curing, the seed is hulled with an ordinary clover huller, with a grain separator equipped with hulling attachments, or by a combine equipped with pick-up attachments or used as a stationary machine. The less the clover is handled the less seed will be lost by shattering. Many troublesome weeds are difficult to separate from crimson clover seed, including field peppergrass (Lepidium campestre), wintercress (Barbarea praecox), and the bulblets of wild onion (Allium spp.), which are probably the worst. Seed of the mustards, rapes, and turnips (Brassica spp.), dock (Rumex crispus), wild geranium (Geranium dissectum), sorrel (Rumex acetosella), and catchweed (Galium aparine) are also found in the seed. Little barley (Hordeum pusillum) is a pest in unhulled seed, and the use of such seed will naturally increase the prevalence of this weed.

U. S. GOVERNMENT PRINTING OFFICE: 1947

For sale by the Superintendent of Documents, U. S. Government Printing Office
Washington 25, D. C. — Price 5 cents