Yellow clover when sown is usually sown with other grass mixtures, and along with grain as a nurse crop; hence, that preparation of the soil suitable for the nurse crop will also be found suitable for the clover. It is, moreover, a hardy plant, insomuch that in some instances, if the seed is scattered over unplowed surfaces, as those of pastures, in the early spring, a sufficient number of plants will be obtained to eventually establish the clover through self-seeding.
The seed is usually sown in the early spring, but in mild latitudes it may also be sown in the early autumn. It may be sown by the same methods as other clovers. (See [page 267].) It is usually sown to provide pasture, the seed being mixed with that of other pasture plants before being sown. As the plants, like those of the small white variety, have much power to increase rather than decrease in pastures, it is not necessary to sow large quantities of seed, not more usually than 1 pound to the acre. But should the crops be wanted for seed, then not fewer than 3 to 5 pounds per acre should be sown and without admixture with other grasses or clovers. When the plants once obtain a footing on congenial soils, there is usually enough of seed in the soil to make a sufficient stand of the plants in pastures without sowing any seed, but since the seed is usually relatively cheap, where an insufficient supply in the soil is suspected, more or less seed should be sown.
Since the stems of yellow clover plants become tough as the season of growth becomes considerably advanced, where it forms a considerable proportion of the pasture the aim should be to graze most heavily during the early part of the season. The plants do not make much growth during the autumn. It would probably be correct to say that it can grow under conditions more dry than are suitable for white clover, and, consequently, it is more uniformly prominent in evidence in permanent pastures when it has become established.
Yellow clover is not a really good hay plant, owing to its lack of bulkiness. But in some soils its presence may add considerably to the weight of a crop of hay, of which it is a factor.
This plant produces seed freely. The seeds are dark in color and weigh 60 pounds to the bushel. The seed matures early, usually in June or July, according to locality. The methods of harvesting, threshing and preparing the seed for market are substantially the same as those adapted in handling small white clover. (See [page 272].)
While yellow clover is not the equal of the small white clover in adaptation to our conditions, it would seem that there are no reasons why it should not be sown to a greater extent than it is sown under American conditions. A plant that is so hardy, that provides a considerable quantity of reasonably good pasture, that stores nitrogen in the soil, and that, moreover, does not stay in the soil to the extent of injuring crops that follow the breaking up of the pastures, should certainly be encouraged to grow.
SAND LUCERNE
Sand Lucerne (Medicago media), sometimes designated Medicago falcata, is probably simply a variety of the common alfalfa (Medicago sativa). Some botanists, however, look upon these as two distinct species. Others believe that Medicago sativa, with blossoms ranging from blue to violet purple, and Medicago falcata, with yellow blossoms, are two distinct species, while Medicago media, with blossoms ranging from bluish and purple to lemon yellow, is a hybrid between these. The name Sand Lucerne has doubtless been given to this plant because of the power which it has to grow in sandy soils.
Sand lucerne is so nearly like common alfalfa in appearance and habits of growth, that until the blossoming season, careless observers cannot distinguish between the plants. (See [page 114].) Sand lucerne, however, has a more spreading habit of growth than common alfalfa, the seed-pods are less coiled and the seeds are lighter. The root system is strong and the roots are probably more branched than those of ordinary alfalfa. Under Michigan experience, given in Bulletin No. 198 of the Michigan Experiment Station, it has shown considerably higher adaptation to light, sandy and gravelly soils than the former. The feeding properties of sand lucerne would not seem to be far different from those of common alfalfa (see [page 119]), but it is claimed that the former is considerably less liable to produce bloat in cattle and sheep than the latter.
Sand lucerne is probably native to Europe and Asia. Some attention is given to growing it in Germany, the principal source from which comes supplies of seed at the present time. It was introduced into Michigan by the experiment station of that State in 1897, and its behavior in several trials made to grow it on sandy and gravelly soils in various places, has, on the whole, been encouraging.