ESCULENT-ROOTED PLANTS.— THE POTATO. 



213 



vour and quality. We speak of flavour 

 and quality, or fitness for tlie table, and 

 not of their chemical constituents. Mr 

 Johnston, in " Elements of Agricultural 

 Chemistry and Geology," p. 327, has shown 

 that the quantity of starch is larger in po- 

 tatoes which are grown upon land long 

 in arable culture, than upon such as are 

 newly brought into cultivation or broken 

 up from grass. One peck of potatoes, 

 grown upon land near Paisley, which had 

 been almost constantly under crop for the 

 last thirty years, produced 7 lb. of starch; 

 while another peck, gTOwn on a bleach- 

 gi'een, newly broken up, yielded only 4 

 lb. There is land in Cornwall, and also 

 in Essex, that has yielded crops of pota- 

 toes annually for nearly as many years ; 

 but although the crops in both cases are 

 both early and abundant, we have ever 

 considered them inferior in flavour, at the 

 table, to such as were grown from new 

 land. In well-drained peaty soil they 

 prosper, if not at too high an altitude. 

 Clay soils produce waxy, and sandy soils 

 mealy potatoes ; and some soils have the 

 property of changing the character of a 

 variety entirely. Clay soils, in the pre- 

 sent state of the potato disease, should be 

 avoided. Out of 163 cases in England, 

 1 29 were returned as having suffered much 

 by the disease. In Scotland, 1 6 cases es- 

 caped out of 27 ; but in Ireland and Wales 

 there was scarcely an exemption from dis- 

 ease. Whereas in peaty soil, Mr Stephens, 

 in " The Book of the Farm," vol. ii. p. 402, 

 informs us, " out of 32 cases of the culti- 

 vation of the potato in moss in England, 

 only 5 suffered much, and 17 little, while 

 10 escaped altogether; of 31 cases in Scot- 

 land, 9 were bad; of 41 Irish cases, only 

 2 suffered much, 24 little, and 15 escaped. 

 The conclusion is — in pure, well-drained 

 peat moss, potatoes suffer very little from 

 disease." 



In poor soils, manure must be applied, 

 and this should be of the nature of half- 

 decayed leaves or littering matter, to keep 

 the ground open and dry, particularly if 

 the soil is retentive or the locality wet. 

 Besides, manure in the state of either of 

 these will undergo progressive decompo- 

 sition along with the growth of the crop, 

 and become reduced to a soluble condi- 

 tion, in which state only manurial appli- 

 cations can be of any use, about the same 

 time that the tubers are forming and 



VOL. II. 



swelling, at which period the plant stands 

 most in need of increased nourishment. 

 Very decomposed rich manure, applied at 

 planting the sets, may be prejudicial in 

 morewaysthan one, particularlyif brought 

 into close contact with them. It cannot 

 be of much benefit, because, by the time 

 the plants really do require manurial as- 

 sistance, this very rotten application will 

 have become soluble and commingled with 

 the soil. Not that in this way it is en- 

 tirely lost; on the contrary, it is absorbed 

 by the soil, and ready to be given out to 

 the spongioles as they are formed : but un- 

 fortunately, as in general applied upon the 

 drill-system, one-half of its fertilising in- 

 gredients descend, or are washed down per- 

 pendicularly to where it was placed ; while 

 the other half, and perhaps the most va- 

 luable — the gaseous portion — ascends up- 

 wards in a perpendicular direction also, 

 leaving the broad spaces between the rows 

 destitute of enrichment altogether. Ne- 

 cessity has long compelled the British 

 agriculturists to adopt this mode of apply- 

 ing manure, because of the difficulty in 

 obtaining a sufficient quantity to meet 

 their extensive demand — and no doubt, for 

 turnips and similar deep-rooting plants, 

 the rule is unexceptionable ; but the roots 

 of potatoes take an entirely different di- 

 rection in search of food from those of the 

 turnip, carrot, mangold-wurzel, &c., for 

 these extend downwards, and occupy a 

 narrow line in the direction of the row ; 

 and from the fusiform character of the 

 two last, it would be inexpedient to en- 

 courage the enlargement of any lateral 

 fibres they might send out, as each of 

 these would either rob the principal root, 

 or enlarge some of the lateral fibres into 

 side roots, and cause in them that mal- 

 formation known technically as " fork- 

 ing." Thus manure cannot be kept too 

 close to the roots of such plants, and 

 therefore laying it in the drills is per- 

 fectly .correct. Not so, however, with the 

 potato, whose roots ramify in all directions 

 horizontally in search of food, and there- 

 fore require that the ground should be 

 equally manured all over. This plant 

 also requires the greatest quantity of azote 

 at the later periods of its growth, when 

 the tubers are swelling, because they con- 

 tain a much greater amount of that sub- 

 stance than the leaves. Manures, there- 

 fore, to be beneficial to this crop, should 



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