1350 ENCYCLOPEDIA OF AGRICULTURE. sumi.kmem. 



B374. In both these plots the pi nils were highly vigorous, and early in advance of others planted in the 

 ordinary manner. The potatoes WOW not too large, but the crop contained a great proportion of small 



8 175. The third plot trus planted the same as the hut, hut the sets a ere cut of the common size. The 

 seed required weighed only lis pounds, the produce, 876 poundi ; being, per acre, nine bushels of seed, 

 and 117 oi pro, inc.- : neit Increase, 108 bushels. The plants In this plot grew fast in the autumn, and pro- 

 duced i>y much the largest potatoes ; i«it tbej did Dot ripen well. 



rhefintrth ]>h>t was planted with sets cut of the common size. The seed required weighed twelve 

 pounds, and the produce 376 pounds ; being, per aire, eighteen bushels of seed, and 568 of produce : net 

 increase, 650 bushels. The potatoes in the produce of this last lot were the most equal sized. 



H.177. The result of these experiment* (which were conducted with great care) is entirely contrary to 

 Mr. Knight's theory, and consequent practice, i Quart, Jour. Agr.. toT.1v. p. 411.) In the Transactions 

 of the Horticultural Society, second series, vol. i. p. I IV to 156. (published in August, 1834), an account is 

 given of a Dumber of experiments made with the greatest care and accuracy, under the direction of Pro- 

 lessor Llndley, in the garden of the Horticultural Society, the result of which is conformable to that 

 obtained by Messrs. Drummond. It also appears in the same work that Sir George Mackenzie made 

 experiments of the same kind in ltoss-shire. and found the produce decidedly better from sets than from 

 whole potatoes. (See Gard. Map., vol. x. p. 433. 135. and p. 499.) 



8378 53b, The depth at which the potato should be planted. In warm dry land 9 inches are not too 



deep ; in cold stilf soil, 4 inches would be better ; 6 inches is a good depth for average land. Certain 

 experiments conducted in the Hort. Soc. garden, gave the following results : 3 inches deep gave 

 13 tons: 4 inches. 14 tons; 6 inches, 141 tons ; and 9 inches, 13 tons. At so great a depth as nine 

 inches, sets are apt to perish, unless the soil is dry. light, and warm. The deeper, however, the sets 

 can be safely inserted, the better, for the following reason : potatoes are formed on underground 

 branches; the deeper the set, the more branches will be formed before the shoots emerge from the soil, 

 and consequently the more ample will be the means possessed by the potato-plant of forming tubers. 

 The important practice of earthing up is to effect the same end, by compelling the potato-stem to grow 

 as much as possible under ground. (G. C. 1842, p. 155.) 



8379 5320. Distance at which potatoes ought to he planted. Experiments with regard to the cultiva- 

 tion of potatoes gave the best results from sets containing only one eye in each, both in early and late 

 crops. The most eligible distance between the rows varies according to the richness of the soil and 

 vigour of the sort planted in it. Two feet is the least distance that should be allowed for common sorts, 

 and much less for dwarf early kinds ; but two and a half feet is in general the most proper distance, as it 

 affords sufficient space for earthing up. The distance between the sets in the rows should be about six 

 inches. The formation of tubers depends on the elaboration of sap by the leaves : and this cannot be 

 duly performed unless the leaves are sufficiently exposed to light. When a number of eves are retained 

 in each set, or when whole sets are employed, a crowded growth of small stems is the consequence; or, 

 if one take the lead, some large tubers result from it, and a number of small imperfectly matured ones 

 from the smal stems with shaded foliage. Kquality among the stems tends to produce equal sized 

 tubers, which ought always to be a desideratum ; for a crop of very large and small tubers is neither so 

 good in quality, nor so profitable, as one of medium-sized tubers. Single eyes, planted at the above 

 distance, will best insure this. (G. C. 1841, p. 185.) 



8380—5327. Earthing up potatoes, according to Mr. Peter Mackenzie, probably originated in wet un- 

 drained soils, in order that the roots might be raised above stagnant water. The result of an experiment 

 proved that a very slight degree of earthing up gave fully a third more of increase of tubers, of better 

 quality than those which had been deeply earthed up ; while potatoes not earthed up at all gave a pro- 

 duce equal to those slightly earthed up, but rather inferior in quality, from many of the potatoes having 

 their sides green from exposure to the light. (Q. J. A., vol. xiii. p. 363.) Earthing up potatoes has no 

 doubt to a certain extent the same bad effect as earthing up turnips, carrots, or parsneps, that of pre- 

 venting the tuber from swelling so much as it would otherwise do. 



8381. The inutility of earthing potatoes, provided the soil be deeply worked, and highly pulverised, 

 proved experimentally in the county of Carlow. Potatoes earthed up in the usual way produced 10 per 

 cent, less than unearthed potatoes. (Q. J. A , vol. v. p. 191.) A good deal depends on the variety of the 

 potato, the stolons of some, such as the Irish apple for example, having a tendency downwards, while 

 others, such as the cup potato, have a tendency to rise out of the soil. 



«382. — 532K. The uselessness of earthing up potatoes has been pointed out by Mr. Hayward ; and, in- 

 dependently of the effect of earthing up, and other operations between the rows, in destroying weeds and 

 loosening the soil, we should think his practice the best. He says, that a farmer who simply hoed the 

 soil between the rows of potatoes in one of his fields, had a much larger crop than he had in an adjoining 

 field, where the rows were earthed up with the greatest care. A potato placed an inch only under the 

 surface of the soil will produce a greater number of tubers than one planted at the depth of a foot. " I 

 have no doubt," says Mr. Hayward, " if potatoes are planted shallow, and placed wide enough apart to 

 admit of the stems being laid down after the young potatoes are formed ; and if the earth between them 

 was then thrown over five or six inches thick, so as to form a flat surface, that it would increase the crop. 

 But this is a very different operation from that which I object to." (Gard. Mag., vol. ix. p. 323.) 



B383.— 5337. Benefit resulting from the removal of potato blossoms. By a well-conducted experiment 

 on a held of two acres, for which the honorary silver medal of the Highland Society was given, it appears 

 that one third part of the field, being those drills from which the blossoms were plucked in the bud, pro- 

 duced thirty bolls, two bushels. One third part from which the blossoms were plucked when in full 

 flower produced twenty-seven bolls, three bushels ; and one third part, being those drills on which the 

 plants were allowed to ripen their seed, produced twenty-six bolls. The difference here, in favour of 

 plucking off the blossoms as soon as they appear, instead of allowing them to remain and ripen their 

 Seed, is nearly one sixth part of the produce. (Highland Soc. Trans., vol. x. p. 237.) 



R384 — 5342. Potatoes should never be covered with straw excepting on the outside of the earth, for 

 straw soon decays, and communicates a bad flavour to the potato. Quantity of sets to an acre 24 bushels, 

 the rows 3 ft. apart, and the sets 6 in. distant in the rows. 



8385. — 5348. Produce of potatoes. Mr. Knight raised 34 tons and Mr. Parker 52 tons per acre; a ton is 

 40bushels. (G.C. 1841, p. 247.) 



8386. — 5354. Potatoes mai/ be preserved by being rasped or ground to a pulp, afterwards pressed into 

 dry cakes by Bramah's or any other powerful press, and then dried like cheeses. Potato cakes of this 

 sort have been found to keep for years perfectly sweet ; and, as a great deal of nutriment is thus put into 

 very little bulk, it is thought by some that ships bound for long voyages might find it advantageous to 

 lav in their stock of potatoes in this form. ( Quart. Jour. Agr., vol. iv. p. 4x:i. 1 



8387. Potato flour was shown at Messrs. Dnnumond's exhibition at Stirling in 1832, which was thirty- 

 eight years old. It was made from damaged potatoes, which, it seems, answer as well as sound ones, and 

 was iii the finest condition. (Quart. Jour. Agr., vol. iv. p. 414.) 



«3kh 53i)0. Potato haum forms a rich and excellent manure for wheat, at the rate of four acres of 



haum to one of wheat, ploughed in green immediately before sowing the wheat. It is 'ound decidedly 

 superior to stable-yard dung. The mode of preparing it is simply to pull up the stems, and to avoiu 

 burying potatoes with it. however small they may be. (A.Gorrie, in Countri/ Times, October, 1831.) 



5363, Good beer can be produced from potatoes by grating them to a pulp, mixing it well with 

 boiling water, and then adding ground barley malt. The . quid, being drawn oil', is to be hopped in the 



