This section is from the book "Commercial Gardening Vol4", by John Weathers (the Editor). Also available from Amazon: Commercial Gardening, A Practical & Scientific Treatise For Market Gardeners.
The Turnip has developed from a hardy British biennial (Brassica Rajxi), and, with the Swede (B. campestris Rutabaga), constitutes a very important Cruciferous crop in all parts of the British Islands, from the Orkneys to Land's End, in Great Britain, and from Donegal to Cork and Wexford, in Ireland. The French Turnips are descended from B. Napus, and are considered to be sweeter and better flavoured than the Common Turnip. According to the Returns of the Board of Agriculture and the Department of Technical Instruction, Ireland, there are in round figures about 1.800,000 ac. in the United Kingdom devoted to Turnips and Swedes, the last-named being, of course, more a farmer's crop than a market gardener's. The largest Turnip- and Swede-growing counties in England are: Yorkshire, 175,000 ac.; Norfolk, 110,000 ac: Lincolnshire, 109,000 ac; Hampshire, 54,000 ac; Devon, 48,000 ac: Suffolk, 44,000 ac; Wilts, 36,000 ac; Northumberland, 34,000 ac; Salop, 32,000 ac; and Dorset, 31,000 ac. There are several counties having over 20,000 ac. each, and many more with considerably over 10,000 ac. each. In Scotland, which has over 438,000 ac. under the crop, the largest Turnip-growing counties are: Aberdeen, 86,000 ac; Forfar, 32,000 ac; Perth, 26,000 ac; Berwick, 25,000 ac; Fife, 22,000 ac: Banff, 21,000 ac; and Roxburgh, 20,000 ac. There are a dozen other counties with 11,000 to 20,000 ac. each.
Ireland has about 280,000 ac. of Turnip land; in 1899 it had over 300,000 ac The province of Leinster has over 91,000 ac; Ulster, 89,000 ac; Munster, 73,000 ac; and Connaught, 24,000 ac. The greatest Turnip-growing counties are: Cork, 35,000 ac; Wexford, 20,000 ac; Tipperary, 18,000 ac; Donegal and Down, each 17,000 ac: Londonderry, 13,000 ac; and Queen's County, 11,000 ac.
Wales is also well provided with Turnip fields, having a total area of nearly 58,000 ac. The county of Denbigh has 8000 ac; Glamorgan and Montgomery, 6000 ac. each; followed by Anglesey, Pembroke, and Radnor, each with 5000 ac.
The average yield per acre is about 20 tons. That much better results than this could be attained there is no doubt, and as much as 36 tons per acre have been recorded. Something like 130,680 plants can be grown on an acre of ground. Taking a nice saleable-size turnip as weighing 8 oz., without the top, the yield would be just over 29 tons to the acre. It has been estimated that an acre of Turnips absorbs from the soil 201 lb. of potash, 107 lb. of lime, 79 lb. of sulphuric acid, 66 lb. of chlorine, 59 lb. of phosphoric acid, and 39 lb. of soda. The quantities of these foods will vary according to the weight of the crop, which will itself be influenced by good or bad culture. As a set-off against what is taken out of the soil, the tops, if not carted away, will supply from 6 to 10 tons of manurial material per acre, thus relieving the pressure on the ordinary manure bill. When it becomes necessary to apply manures for Turnips the nature of the soil must be considered. For stiffish land about 10 tons of stable manure, 4 cwt. of superphosphate, 1/2 cwt. of sulphate of ammonia, and 4 cwt. of kainit may be applied, the latter before the crop is sown and after the stable manure has been dug in. On light land about twice as much stable manure and kainit may be necessary.
Like other plants of the Brassica family the Turnip is subject to attack from the Clubroot Fungus (Plasmodiophora brassicoe). In soil that has been more or less heavily dunged, and not limed, this disease is prevalent, and is very difficult to eradicate. Notwithstanding the many highly boomed remedies, lime in some form or another appears to be the best and cheapest antidote. Badly infested soil should have about 1 bus. of lime to the rod (160 bus. to the acre) dug in during the winter. This will check any acidity caused by the decaying manure and moisture, and thus destroy the conditions suitable for the fungus. It may take four or five years to eradicate the pest, but half the quantity of lime only will be necessary after the first year.
TURNIPS FOR STREET SALE Turnips badly Infested with maggots of Gall Weevil. Notice the warty growths.
FORCED RHUBARB FOR MARKET.
Another troublesome and unsightly disease is that caused by the Cabbage Gall Weevil (Ceutorrhynchus sullicollis). This pest lays its eggs flush with the ground on the young "bulbs". In due course the young maggots are hatched out and penetrate the tissues, thus causing the sap to exude and form wart-like swellings. Inside these the little white maggot is perfectly safe, and cannot be reached by the most virulent insecticides. After several years of experimenting, the only sure remedy for this pest is prevention. The frequent use of the hoe in the early stages of the crop seems to keep the plants perfectly free from the pest. It appears that the movement of the soil against the plants detaches the newly hatched maggots from the stems, and, being thus deprived of their natural food, they soon die. The Plate shows a load of turnips to be badly infested with the Cabbage Gall Maggot. [j. w].
The Spring Turnip may be called the crop of the market gardener, while that of the autumn and winter may be termed the farmer's crop. Spring Turnips want rich warm soil, well cultivated. There is an old tradition among gardeners that the first sowing must not be made before the first full moon in March, or they will bolt. The earliest varieties are the strap-leaved White- or Purple-topped Milan. These, drilled in rows 1 ft. apart, and singled to 6 in., should come to market early in June. The Early Snoivball (fig. 499) is a good sort for second sowing, followed by the New Model, which requires more room than the other two. By arranging the sowings at intervals of ten days or a fortnight a supply can be kept up till late July, when the market can be left to the farmer. Spring and summer turnips are not of first value unless they are clear and white in the skin. To obtain this the land must be freed from the grubs of the Turnip Beetle, which eat unsightly holes in the face of the turnips. For this purpose one of the several preparations that give off a gas poisonous to insect life in the soil should be applied according to directions before the seed is sown. The Turnip Fly may be a trouble in a dry spring to the young seedlings. A good preventive against this destructive pest is to sow soot over the land as soon as the first seedlings appear above ground, and a second one as soon as the seed leaves are well developed. The sowings of soot should be made in early morning, while the leaves are damp, but not when there is a frost. [W. G. L].
Fig. 499.-Turnip-Early Snowball.