Free Use of Lime.—The conditions requisite to success in alfalfa-growing are not numerous, but none can be neglected. Alfalfa should be given a calcareous soil when possible, but an acid soil can be made favorable to alfalfa by the free use of lime. There must remain a liberal amount after the soil deficiency has been met, and when the use of lime is on a liberal scale, the pulverized limestone makes the safest carrier. However, 50 bushels of stone-lime per acre can be used safely on any land that is not distinctly sandy, and that amount is adequate in most instances.
Inoculation.—The necessity of inoculation has been discussed in Chapter IV. Eastern land would become inoculated for alfalfa if farmers would adopt the practice of mixing a little alfalfa with red clover whenever making seedings. Some alfalfa plants usually make growth, securing the bacteria in the dust of the seed, presumably. The addition of one pound of alfalfa seed per acre would assist materially in securing a good stand when the day came that an alfalfa seeding was desired.
Fertilization.—The ability of alfalfa to add fertility to the farm, and directly to the field producing it when all the crops are removed as hay, does not preclude the necessity of having the soil fertile when the seeding is made. The plants find competition with grass and other weeds keen under eastern skies where moisture favors plant-life. In their first season this is markedly true. There should be plenty of available plant-food for the young plants. Stable manure that is free from the seeds of pernicious weeds makes an excellent dressing. It is good practice to plow down a heavy coat of manure for corn and then to replow the land for alfalfa the next season. A top-dressing of manure is good, affording excellent physical condition of the surface for starting the plants. Eight tons per acre make a good dressing.
If land is not naturally fertile, mineral fertilizers should be applied. A mixture of 350 pounds of 14 per cent acid phosphate and 50 pounds of muriate of potash is excellent for an acre of manured land. In the absence of manure, 100 pounds of nitrate of soda and 50 pounds of muriate of potash should be added to the mixture. If the materials are wet, a drier must be used. The fertilizer should be drilled into the ground prior to the seeding.
A Clean Seed-bed.—Much failure with alfalfa is due to summer grasses and other weeds. The moisture in our eastern states favors plant-life, and most soils are thoroughly stocked with the seeds of a large number of weeds. The value of blue-grass and timothy would be comparatively small if they were not capable of monopolizing the ground when well started and given fertility. Alfalfa plants are less capable of crowding out other plants, and especially in their first season. Their habit of growth is unlike that of grass. Rational treatment of alfalfa demands that the surface soil be made fairly clean of weed seed, and this applies with peculiar force to annual grasses, like fox-tail. If attention were paid to this point, failures would be far less numerous.
Old grass land should not be seeded until a cultivated crop has followed the plowing. The land should be in good tilth, and capable of producing a good crop of any sort. Alfalfa is not a plant for poor land, although it does add organic matter and nitrogen.
Varieties.—There is only one variety of alfalfa in common use in this country, and the western-grown seed sold upon the market is known simply as alfalfa. Bound up in this one so-called variety are many strains differing in habit of growth, and their differentiation will occur, just as it has in the case of wheat, and is now proceeding slowly with timothy. The eastern grower at present should use the variety of the west that is furnishing nearly all the seed produced in this country. There is a variety known as Sand Lucerne that has shown value for the light, sandy soils of Michigan. The Turkestan variety was introduced for dry, cold regions, but does not produce much seed.
Clean Seed.—Care should be exercised to secure seed free from impurities. If one is not a competent judge, he should send a sample to his state experiment station for examination. The practice of adulteration is decreasing, but the seed may have been taken from land infested with pernicious weeds.
The impurity most to be feared is dodder. There are several varieties, the seeds varying in size and color. The same pest may be found in clover fields, but the injury is less because the clover stands only two years. The dodder seed germinates in the soil, and the plant attaches itself to the alfalfa, losing its connection with the soil and forming a mass of very fine vines that reach out to other alfalfa plants. In this way it spreads, feeding on the sap of the host plants and killing them.
When the infestation is in only a few spots in the field, the remedy is to cover with straw, soak with kerosene oil, and burn. All the infestation at the edges of these spots must be destroyed.