The reason for mixing clover and grass is at once seen. The true grasses, so far as science now shows, get all their nitrogen from the soil; hence they more or less exhaust the soil. But, as several times explained in this book, the clovers are legumes, and all legumes are able by means of the bacteria that live on their roots to use the free nitrogen of the air. Hence without cost to the farmer these clovers help the soil to feed their neighbors, the true grasses. For this reason some light perennial legume should always be added to grass seed.
Fig. 226. Single Plant of Giant Millet
It is not possible for grasses to do well in a soil that is full of weeds. For this reason it is always best to sow grass in fields from which cultivated crops have just been taken. Soil which is to have grass sowed in it should have its particles pressed together. The small grass seeds cannot take root and grow well in land that has just been plowed and which, consequently, has its particles loose and comparatively far apart. On the other hand, land from which a crop of corn or cotton has just been harvested is in a compact condition. The soil particles are pressed well together. Such land when mellowed by harrowing makes a splendid bed for grass seeds. A firm soil draws moisture up to the seeds, while a mellow soil acts as a blanket to keep moisture from wasting into the air, and at the same time allows the heated air to circulate in the soil.
In case land has to be plowed for grass-seeding, the plowing should be done as far as possible in advance of the seeding. Then the plowed land should be harrowed several times to get the land in a soft, mellow condition.
If the seed-bed be carefully prepared, little work on the ground is necessary after the seeds are sowed. One light harrowing is sufficient to cover the broadcast seeds. This harrowing should always be done as soon as the seeds are scattered, for if there be moisture in the soil the tiny seeds will soon sprout, and if the harrowing be done after germination is somewhat advanced, the tender grass plants will be injured.
There are many kinds of pasture and meadow grasses. In New England, timothy, red clover, and redtop are generally used for the mowing crop. For permanent pasture, in addition to those mentioned, there should be added white clover and either Kentucky or Canadian blue grass. In the Southern states a good meadow or pasture can be made of orchard grass, red clover, and redtop. For a permanent pasture in the South, Japan clover, Bermuda, and such other local grasses as have been found to adapt themselves readily to the climate should be added. In the Middle States temporary meadows and pastures are generally made of timothy and red clover, while for permanent pastures white clover and blue grass thrive well. In the more western states the grasses previously suggested are readily at home. Alfalfa is proving its adaptability to nearly all sections and climates, and is in many respects the most promising grass crop of America.
Fig. 227. Bermuda