The preparation of the soil prior to seeding with grasses and clovers is usually intended primarily for the benefit of the nurse crop. To get a good catch, it is important that the surface soil be of fine tilth, friable, well-drained and contain a liberal supply of decaying vegetable matter. The tender seedling plants require plenty of moisture, though they are injured by an excess. If the soil lacks humus and a hard crust is formed over its surface, growth will be stunted and the young plants will suffer from even a few hot, dry days.
Seeding to grasses and clovers should follow a cleaning crop that has had deep and thorough cultivation. The suppression of perennial weeds should precede the making of a meadow. Such a location as a clayey hillside, where the soil is apt to become hard after heavy rains, may be greatly improved by a light top-dressing of rotted stable manure, which should be incorporated with the surface soil by harrowing. On low, wet lands the best possible surface drainage should be provided, even for grasses that like abundant moisture. On the dryer prairie soils the subsoil should be packed to keep the moisture near the surface until the seedlings have grown robust.
Nurse crops are designed, in part at least, for the protection of seedling plants of grasses and clovers. When all the soil moisture does not have to be saved for the meadow, a light nurse crop screens the seedlings from the burning heat of the sun; it helps to suppress weeds until the grasses have sufficient vigour to compete with them; and it may give a return from the land while the meadow is developing. Wheat or barley is generally considered most satisfactory as a nurse crop. Oats, even with thin seeding, are later to mature and apt to make too much shade. Standing in a nurse crop, one should be able at any time during the growing season to see the young grass ten or twelve feet away. The nurse crop should be ready to harvest as soon as the grasses commence to tiller or stool out and the clovers or other legumes to develop new shoots or branches from the crown.
In districts where the rainfall is less than thirty inches, or not well distributed throughout the growing season, the nurse crop may rob the young fodder plants of necessary moisture. In some seasons a good stand of Red Clover is difficult to obtain, partly because of the lack of humus in the soil, but also because the nurse crop, frequently oats, robs the young plants of the available moisture. If the meadow is of more importance than the nurse crop, it is advisable in a dry season to dispense with the latter; or, if planted, to cut it for fodder before the seedlings perish from thirst.
The depth of seeding depends on the kind of seed, the character and condition of the soil, and the moisture. It is said that no seed should be planted deeper than four times its diameter. When growing wild, fodder and pasture plants drop their ripe seeds, which germinate very near or on the surface of the soil. But nature is more wasteful than the farmer can afford to be; he should provide the best possible conditions for the development of a perfect seedling.
Method of seeding: When the soil is quite firm, as for spring seeding on fall wheat land, harrowing after broadcast seeding, if the land is reasonably dry, makes a good tilth and covering for the grass and clover seeds and is beneficial to the wheat plants. When seeding after deep spring cultivation, the fodder crop seeds may be sown by the seeder in front of the grain drills and then rolled and given a stroke with a weeder; if the subsurface soil is firm and the surface in fine tilth the grain drill may be followed by a weeder alone to level the soil and redistribute the seeds that have been thrown together between the drills. If the weather is favourable, it is sometimes satisfactory, although bad practice, to broadcast the seed after the nurse crop has been sown and depend on rains to cover and protect it during germination. Any method that will insure its even distribution and a covering of half an inch is preferable to surface seeding without covering. Heavy rains are apt to wash the seed lying on the surface into the furrows and ditches. Then, too, many kinds of grass seeds that require two or more weeks to germinate may be destroyed if exposed on the surface. Sowing from one to one and a half inches deep is sometimes recommended for Alfalfa and other fodder crops on prairie soils. In semi-arid districts Alfalfa for seed crop may be thinly sown in drills from twenty to thirty inches apart. If the soil is very dry the growth will be dwarfed, but their deep roots enable the plants to get moisture enough to produce a fair yield of good seed.
Implements are specially designed for sowing grass and clover seeds. Most grain seeders are fitted with an attachment, sometimes in front and sometimes behind the drill tubes, for sowing fodder plant seeds. If the surface is in fine tilth, and the grain drill is followed by a weeder or light harrow, to level the soil, the fine seeds are not apt to be covered too deeply, which sometimes happens in lumpy clay. The hand broadcast seeder, with a revolving disc to scatter the seed, is a satisfactory implement for most grass and clover seeds and is quite generally used. When seeding with mixtures, however, it has the same disadvantage as scattering the seed by hand; the heavier clover seeds are thrown so much farther than the finer grasses that the distribution may be unequal.
Thick seeding, especially for meadows of short duration, is commonly recommended by seedsmen and experienced farmers. For hay the advantage, as a rule, is not in an increased yield, but rather in the finer quality of the crop. If soil and weather are favourable, a satisfactory stand of Timothy, Alsike and Red Clover, for instance, may be had by sowing four, three and six pounds respectively per acre. By sowing six pounds of Timothy, four of Alsike and ten of Red Clover, the chance will be better for securing a good stand of plants, suppressing the weeds, and obtaining a large yield of hay of good quality. The cost of the additional seed should be considered as inexpensive insurance of satisfactory results. Thick seeding is not recommended for a seed crop. Both yield and quality of the seed are inferior when the stand is too thick.