Page:Collier's New Encyclopedia v. 10.djvu/64

LEFT TTJBNIP 46 TURNIP pounds. Though the turnip is of great value for feeding stock, it is not very nutritious, no less than 90 to 96 parts of its weight actually consisting of water. Garden turnips are sown from the end of March to the end of August; field turnips generally in June, it being requisite that they should not be sown so soon as to incur a risk of their throw- ing up flower stems in the first year, which, when it takes place, preve:.::s in a great measure the swelling of the root and renders it coarse and fibrous. In dry weather the plants are apt to throw up flower stems, and so disappoint the hope of the gardener. Moist cloudy weather is most favorable. Garden turnips are sown and allowed to grow much closer than field turnips, being gradually thin- ned out, and the thinnings used even when of small size. The garden turnips are generally of comparatively small size, more rapid in growth, and more delicate. The Swedish turnip, or ruta baga, which was introduced into cultiva- tion in Great Britain from the N. of Europe, more recently than the common turnip, and has proved of great value to the farmer, is regarded by some botan- ists as a variety of the same species, and by some as a variety of B. 'napiis, but more generally as a variety of B. cam- pestris, a species common in cornfields and sides of ditches in Great Britain and the N. of Europe. The cultivated turnip grows best in a rich free soil. The mode of culture varies with the soil. Where the soil is light and dry a smaller amount of plgw- ing, harrowing, and drilling is necessary than on stiff soils. The turnip is not well suited to clay soils, though it is often grown on them. A complete pulveriza- tion of the soil is requisite before the sowing of the seed. On light soils a crop of turnips generally succeeds wheat or oats. Turnip land is generally made up in raised drills by the plow, and the seed is sown by the drilling machine on the top of the narrow ridges, which are about 27 inches wide. Moderate dress- ings of artificial manure, such as super- phopsphate of lime, crushed or dissolved bones, kainit and nitrate of soda, or other such manures, produce great crops of turnips. The more general practice, however, is to give a mixed dressing of farmyard dung and artificial manure. The young plants are thinned out by hand hoe to from 9 to 11 inches apart, and the ground is stirred and carefully kept clean by the plough or horse hoe. The turnip crop is thus of great use in clearing the land of weeds. In many places part of the crop is eaten on the ground by sheep, which are confined to a small part of the field by means of movable fences. It is common to leave one of each three rows of turnips for this purpose, the other two rows being carried into the farmyard for feeding cattle or stored. Turnips are stored either in a house or conical heaps, cov- ered with straw and earth. They are sometimes protected from frost by being earthed up in rows by the plow. Some kinds are much more easily injured by frost than others; the Swedish turnips least of all. The introduction of the turnip as a field crop is one of the most important events in the history of British agricul- ture. It has rendered possible a rota- tion of crops which has been extremely advantageous, and has made the supply of butcher meat more constant, by pro- viding a supply of winter food for cattle and sheep, whereas formerly all de- pended on the pasture. As a field crop turnips were not raised in Great Britain till the end of the 17th century. Turnip husbandry was introduced into Rox- burghshire from Leicestershire about the year 1764, but was soon carried to a perfection in Scotland far beyond what it had previously reached. The climate of Scotland is well adapted for it, as is also that of Ireland. Turnip crops in Great Britain suffer very much from the two distinct diseases called anbury, or club root, and finger-and-toe. Superior culture is the best means of preventing these diseases. Plants weakened by drought are liable also to suifer from a white mould, a species of Oidium, which attacks the leaves and greatly injures the plant. The turnip crop has to encounter many insect enemies. The most destruc- tive in recent years have been the turnip fly (Phyllotreta nemonim, Chevrolat), which devours the young plants before they are strong enough to be thinned. The leaves of the young turnip plants are also attacked and often much injured by the green fly or turnip aphis. Aphis rapae (Curtis) ; by the maggots of two kinds of Diptera — Phytomyza nigricor- nis (Maquard), the black-leaf miner, and Drosophila plana (Fallen), the yel- low-leaf miner; by the caterpillar of the diamond-back turnip moth, Cerostoma xylostella (Curtis) : by the caterpillar of the common dart moth, Agrotis segehim (Westwood) ; by the grubs of the turnip sawfly. Athalia spinarum (Fabricius) ; and by at least two varieties of weevil, Curculio, the most destructive being the little Curculio, Centorhynchus contractus, 1-14 inch long, which punctures the seed leaves with its rostrum. The diamond-