I. THE POTATO.
BY BYRON D. HALSTED.
The potato is undoubtedly the leading addition which the New World has made to the list of garden vegetables. Its importance as a food plant may be judged from the fact that during the year 1880 over one hundred and sixty-nine million bushels of potatoes were raised in the United States. If we could obtain the total yield in all countries for a single year, the figures would express only the simple fact of vastness. It only need be said that potatoes furnish the larger part of the food for many millions of people. Think of Ireland, for example, deprived of her annual crop of potatoes; it means famine and all its attendant ills.
The common, or Irish potato, as distinguished from the sweet potato, bears the botanical name of Solanum Tuberosum, and belongs to the natural order Solanaceæ. This group or family of plants is characterized by rank scented herbage, often abounding in narcotic poison. The flowers are regular, parts usually in fives, and the ovaries mostly two-celled and many-seeded. Among the more important members of the family are the tomato, egg-plant, cayenne pepper, and tobacco. Belladonna, hyoscyamus, and stramonium are better examples of the poisonous and medicinal properties of the plants in the order, which gives us so wholesome a food as the potato, and so vile a weed as tobacco. The herbage of the potato plant is not unlike that of its first and second cousins, but by means of these narcotic leaves and stems the plant is enabled to transform crude materials into starch and other valuable substances which are afterwards stored up in a suitable form for the use of man. The potato itself, which nearly all persons relish when well prepared for the table, is not a thick root, as many have supposed, but an enlarged underground stem, called a tuber. These thickened subterranean stems bear small leaves, reduced to mere scales, under which are buds, better known as eyes. A potato is as much a stem as the tender and delicious shoots of early spring asparagus. The potato plant has three kinds of stems: those bearing the foliage, those bearing the flowers and the underground stems which may be styled starch-bearing.
The early history of the potato is very obscure. It is doubtless a native of South America, where it has been frequently found in the wild state. The Spaniards are given the credit of first introducing the potato into Europe in the early part of the sixteenth century. It passed from Spain into France, and from there on into Germany and other countries of Europe. The first potatoes to reach England were those carried by Sir Walter Raleigh on his return from Virginia in 1584. “In the time of James the First they were so rare as to cost two shillings (sterling) a pound, and are mentioned in 1619 among the articles provided for the royal household.” The culture of the potato was encouraged by the Royal Agricultural Society. Since 1760 it has become an established garden and field crop, and one it would be a calamity to lose.
The chemical composition of the potato tuber varies greatly according to the conditions under which it has been grown, namely: soil, weather, manure, etc. It contains about seventy-five per cent. of water. The composition of the twenty-five per cent. of dry substance is as follows: protein, 2 per cent.; fat, .03; starch and other carb-hydrates, 20.7; fibre, 1.1; ash, .09. By protein is understood the various compounds containing nitrogen, like the gluten of wheat, white of egg, etc. This is considered the flesh-forming part of a food. Lean flesh is made up largely of protein compounds, or albuminoids, as they are sometimes called. The carb-hydrates contain no nitrogen, and are compounds of carbon, hydrogen and oxygen. Among the most familiar of this class are starch, sugar, and gums. The carb-hydrates, in contrast with the flesh-forming protein compounds are frequently called heat producing substances. This classification aids in giving a general idea of the part the two groups play in the animal economy. Both classes of foods are required, the amount of each depending upon the wear and tear of the body and the conditions of temperature, etc., under which the animal lives. A man who is working hard needs more of the protein compounds to build up the muscles than the person of leisure. When exposed to severe cold, an increase of the starchy substance is demanded to make good the losses caused by the excess of animal heat produced. From the average of many chemical analyses given above, it is seen that the potato is a heat-producing food, and not a muscle-forming food. The fat in foods—of which there is very little in the potato—is used both as fuel and to build up the fatty substance of the body. The proteins or albuminoids are the most expensive portions of any food; the fats come next, and the carb-hydrates last. (In this way a chemist is able to compute the nutritive value of a food from the per cent. of the classes of constituents found present by analysis.) Wheat contains about eleven per cent. of protein, and seventy per cent. of carb-hydrates. There is far less water, but more than that, it has a higher ratio of protein. It is a richer food. Corn has the same per cent. of starchy matter, but only nine per cent. of the albuminoids. It is not so rich a food as wheat. Beans and peas have about fifty per cent. of oil and starch and twenty-five per cent. of the flesh-formers. This is a very high protein ratio, and those grains approach closely to the composition of meats, and may replace them to a large extent. This is all to show that both chemistry and culinary experience do not rank the potato as a rich food. It serves the animal economy best when eaten with some other substance far richer in protein. Thus we have meat and potatoes as a wholesome and complete food.
The potato thrives in an open, warm, deep, mellow and rich soil. If the soil is not naturally fertile it needs to be supplied with well rotted manure; or if this is not available in sufficient quantities, supplement with some good commercial fertilizer. Thorough tillage, that is, frequent plowing and harrowing, will supply two other essentials, namely: depth and mellowness. Drainage may be necessary to remove the excess of water, the presence of which shuts out the air, and renders the soil cold and unfit for growing plants. A soil that will grow a good crop of corn will usually yield a paying crop of potatoes. Both corn and potatoes grow for only a short season, and have no time to wait for plant food. The roots need to have all the plant food they can absorb close within reach. As a rule, land can not be made too rich for potatoes.
There is a wide difference of opinion as to the size and manner of cutting the “seed” potatoes. If we will remember that a potato is a stem it will be seen that planting potatoes is virtually setting out cuttings; as much so as when portions of a grape vine or a currant cane are placed in the ground. The potato to serve as “seed” should be well matured and carefully kept through the winter. It is poor economy to plant small and half matured tubers. As much care should be taken with the “seed” potatoes as in the selection of scions, with which to engraft a tree. This leads to another very important point in potato growing. Be sure and plant good varieties. The list of names of the varieties of potatoes would fill a volume. The Early Rose has been for several years the type of excellence. The Beauty of Hebron takes a front rank for quality and productiveness. The Peach Blow has long been a favorite, though now less grown. The White Elephant, Snow Flake, and Burbank are three of the better sorts. The point of growth in a potato is the bud or “eye,” and the substance of the tuber around this eye furnishes it with nourishment for its initial growth. The results of experiments uphold the deductions of science that it is best to cut large potatoes to single “eyes,” guiding the knife so that each bud shall have an abundance of surrounding substance. The cut pieces may be planted in hills two and one-half feet each way, or in drills. A rapid and satisfactory method is to drop the pieces fifteen inches apart in the furrows made by a light plow. If placed in every third furrow, the rows will be wide enough for horse cultivation. In this way the plow prepares the place for the “seed,” and afterward covers it. When the potato plants are just coming through the ground, the surface may be stirred with the back of an ordinary harrow. This loosens up the soil and kills the young weeds. The further culture consists in frequently passing the cultivator between the rows to keep the surface soil open and free from weeds. The soil may be thrown toward the vines after they have attained considerable size.
The potato has met with some serious enemies. The worst pest of late years is the Colorado beetle. This is now so wide spread and well known that a description is unnecessary. The remedies are numerous, but Paris green and London purple are the most effective. These arsenical compounds are applied in both the dry state and mixed with water. The latter is generally considered the better method. A teaspoonful of either the “green” or “purple” is stirred in a watering-pot and applied to the infested foliage through a fine nozzle. This voracious beetle has a natural enemy in the shape of a mite that sometimes occurs so abundantly as to completely cover the victim. Other insect enemies are the stalk borer and the large potato worm. Burn the vines infested with the former, and pinch off and crush the latter.
The wet rot, so destructive some seasons, is caused by a minute parasitic fungus which grows within the substance of the potato leaves and stems, and afterward descends to the tubers and causes them to decay. Wet and hot weather are particularly favorable for the development of this mould. Nothing has been successfully used to stay its ravages. This rot has swept over Europe, Great Britain and Ireland, at different times, bringing great distress to all the inhabitants, but especially to the lower classes, whose daily food is made up largely of the potato. The tubers should be dug so soon as the fungus is found to have “struck” the foliage. In this way they may be removed before the rot has invaded them. Store the potatoes in a dry and uniformly cool place. As the rot does not come until midsummer, it is best to plant quick maturing varieties, and plant these early. In this way some of the insect enemies may also be avoided. Take it altogether, the potato is an easy and profitable crop to raise.