XII. CULTIVATED CROPS - ROOT CROPS
The events of late years render it necessary to regard this root somewhat differently than was warranted by its previous history. Its value as an article of food, relished alike by prince and peasant, its easy culture, its adaptation to a very wide diversity of soil and climate, and the largeness of its produce, justly entitled it to the high esteem in which it was universally held. Like many other good gifts, it was, however, grossly abused, and diverted from its legitimate use; and advantage was taken of its amazing productive powers to elevate it from the place of an agreeable, wholesome addition to the daily food of the community to that of "the staff of life." In Ireland and the Highlands of Scotland, the people, already in a painfully degraded condition, and contented with the potato as their sole food all the year round, took occasion, from its very productiveness, under the rudest culture, to sub-divide their lands, and marry prematurely, with reckless improvidence, and amid an ever-deepening degradation. We know now, from the utter prostration and helplessness into which this wretched population was at once thrown by the memorable potato disease, the terrible penalty which this abuse of "a good gift" has brought directly on the miserable sufferers, and indirectly on the whole community. It will be well if the stern lesson, enforced by famine and pestilence, have the effect of leading to a better social condition. Viewed in this light, the potato disease may yet prove a blessing to the nation. Its continued prevalence, although in a mitigated form, cannot well be regarded otherwise, when we remember the frantic eagerness with which the Irish peasantry replanted their favourite root on the first indication of its returning vigour, and the desperate energy with which they cling to it under repeated disappointments. Apart from this speciality, the precarious health of this important esculent is much to be regretted. It seems contrary to analogy to suppose that it is likely either to be entirely lost or to manifest a permanent liability to disease. It seems more natural to suppose that by-and-by the disease will disappear, or that some efficient remedy fo it will be discovered. Railways afford great facilities for transporting this bulky commodity at little expense to great distances, and thus render the market for it available to a wider district. Apart from disease, this facility of transport would naturally insure its more extended cultivation. This enlarged cultivation of a crop which, to be grown successfully, requires a soil rich in fertilizing matters, has moreover been rendered practicable by the facilities which the farmer now has of obtaining guano and other portable manures.
The varieties of the potato, whether for garden or field culture, are exceedingly numerous, and admit of endless increase by propagating from seeds. It would serve no useful purpose to enumerate here even a selection from the sorts in use in different parts of the country. In Messrs Lawsons Synopsis of the Vegetable Products of Scotland a description of 175 kinds is given, to which the reader is referred for particulars. When the crop is grown for cattle food, bulk of produce will be the primary consideration; but for sale or family use, flavour, keeping quality, and handsome appearance, will be particularly attended to. Exemption from disease is now a momentous consideration, whatever the use for which it is grown. There is this difficulty, however, connected with selections on the score of healthiness, that while in each season since the disease broke out certain varieties have escaped, it is observed from year to year that the exempted list varies, certain kinds that had been previously healthy becoming as obnoxious to disease as any, and others in a great measure escaping that had suffered much before. Indeed, certain parties, from observing that diseased tubers left in the ground have produced healthy plants in the following season, have been induced purposely to plant diseased potatoes, and with good results. This, however, is probably due to the mere fact of their being kept in the earth.
In field culture the potato is frequently grown on a portion of the fallow break; but its appropriate place in the rotation is that usually assigned to beans, with which, in an agricultural point of view, it has may features in common, and in lieu of which it may with advantage be cultivated. As the potato requires to be planted as early in spring as the weather will admit of, thus leaving little opportunity for cleaning the land, and as its mode of growth forbids any effective removal of root-weeds by after culture, it is peculiarly necessary to have the land devoted to this crop cleaned in autumn. Winter dunging facilitates the planting, and is otherwise beneficial to the crop by producing that loose and mellow condition of the soil in which the potato delights. The quality of the crop is also believed to be better when the dung is thoroughly incorporated with the soil, than when it is applied in the drill at the time of planting. A liberal application of manure is necessary if a full crop is expected. The rank growth thus induced renders it, however, more obnoxious to the blight, and hence at present it is more prudent to aim rather at a sound crop than an abundant one, and for this purpose to stint the manure. When it is applied at the time of planting, the mode of procedure is the same as that which will presently be described in the section on turnip culture. The potato sets are prepared a few days before they are expected to be needed. Tubers about the size of an egg do well to be planted whole; and it is a good plan to select these when harvesting the crop, and to store them by themselves, that they may be ready for use without further labour. The larger tubers are cut into pieces having at least one sound eye in each, although two are better. It is of great consequence to have seed-potatoes stored in a cool and dry pit, so that if possible they may be prepared for planting before they have begun to shoot. If there has been any heating in the pit, the potatoes are found to be covered by a rank crop of shoots, which are necessarily rubbed off, and thus the most vigorous eyes are lost, and much of thee substance which should have nourished the young plant is utterly wasted. A sufficient number of dormant eyes are no doubt left, but from the comparatively exhausted state of the tubers, these produce stems of a weaker and more watery character, and more liable to disease than those first protruded. To avoid these evils, gardeners are at pains to invigorate their seed potatoes and husband their whole powers for early and vigorous growth by greening them in autumn, storing them in a cool place with a current of air passing through it, and then in early spring exposing them to light on a floor, whence they are carefully removed and planted with their short green shoots unbroken. Neither the greening nor the sprouting under cover and in the light can ordinarily be practiced on the scale on which the field culture of the potato is conducted. But the important feature in it, viz., so treating potatoes intended for seed that the crop shall be produced from the first and most vigorous shoots, and that these shall obtain the full benefit of the natural pabulum stored up for their use in the parent tuber, should be carefully considered and imitated if possible in field culture.
The report of the meeting of the Edinburgh Botanical Society, on 8th January 1852, bears that "Professor Simpson communicated the results of some experiments made by himself and Mr Stewart relative to the growth of alpine plants after having been kept artificially covered with snow in an ice-house for many months. Seeds and plants when kept in this way during winter, and then brought into the warm air of summer, germinate and grow with great rapidity. Mr Stewart had also made experiments with animals, and he found that the chrysalis so treated produced a moth in eleven days after being brought into the atmosphere, while another chrysalis of the same moth did not do so for three or four months after. In arctic regions the rapid growth of plants during the short summer was well known. Professor Simpson alluded to the importance of similar experiments being made on the different kinds of grain. He referred to the rapidity of harvest in Canada and other countries where the cold lasted for many months, and he was disposed to think that if grain was kept in ice-houses during the winter, and sown in spring, there might be an acceleration of the harvest."
The suggestion for the treatment of seed corn is certainly deserving of trial; but know difficulty of hindering the premature germination of potato sets in the ordinary method of storing them seems to point to them as the peculiarly appropriate subjects of such an experiment.
Potato drills should not be less than 30 inches wide, nor the sets less than 10 or 12 inches apart in the rows. The usual practice is to take the sets to the field in sacks, which are set down at convenient distances for replenishing the baskets or aprons of the planters. When a large breadth is to be planted, a better way is to have the sets in carts, one of which is moved slowly along in front of the planters. A person is seated in the cart, who has by him several spare baskets which he keeps ready filled, and which are handed to the planters in exchange for empty ones as often as required. This greatly economises the time of the planters, and admits of a greater amount of work being accomplished by them in a day. Single-bout drills are quite sufficient so far as the success of the crop is concerned. So soon as the young potato plants are fairly above ground, the drill-grubber should be set to work and followed up without delay by hand-hoeing. Mr Wallace, North Berwick Mains, a most successful cultivator of potatoes, has for many years taken off all the shoots, save one, from the potato sets as they appear above ground, and the prunings are used in filling up blanks; the result has been that the produce of the solitary stem is both larger and of more equal size and quality than when the shoots are all left. A turn of the horse-hoe, and another hand-hoeing after a short interval are usually required, after which the common practice is to earth up the rows by the double mould-board ploughs. There is reason to believe that this latter practice usually does harm rather than good. It no doubt prevents the uppermost tubers from getting greened by exposure to the light, but it is believed that the injury inflicted on the roots which spread into the intervals betwixt the rows far more than counterbalances any benefits that result, or have been supposed to result, from this earthing up. After the plants are a foot high, a slight stirring of the surface to keep down weeds is all the culture that is admissible consistently with the well-doing of the crop.
When the crop is matured, which is known by the decay of the tops and the firmness of the epidermis when the tubers are forcibly rubbed by the thumb, advantage is taken of every dry day in harvesting the crop. With small plots, the fork is certainly the most efficient implement for raising the tubers; but on the large scale, when expedition is of great consequence, they are always unearthed by the double mould-board plough. Alternate rows are split open in the first instance, and then the intervening ones, as the produce of the first is gathered. When a convenient breadth has thus been cleared, a turn of the harrows is given to uncover such tubers as have been hid from the gleaners at the first going over. This work is now very generally accomplished by means of a bulking-plough divested of its wings, and having attached to its sole a piece of iron terminating in radiating prongs. This being worked directly under the row of potato plants, unearths the tubers, and spreads them on the surface by one operation. The potatoes are gathered into baskets, from which they are emptied into carts and conveyed at once to some dry piece of ground, where they are piled up in long narrow heaps and immediately thatched with straw. The base of the heaps should not exceed a yard in width, and should be raised above the surface level rather than sunk below it, as is very usually done. As the dangers to be guarded against are heating and frost, measures must be taken with an eye to both. The crop being put together in as dry and clean a state as possible, a good covering of straw ia put on, and coated over two or three inches thick with earth, care being taken to leave a chimney every two yards along the ridge. By thus keeping the heaps dry and secure from frost, it is usually possible, even yet, to preserve potatoes in good condition till spring. Such diseased ones as have been picked out at the gathering of the crop can be used for feeding cattle or pigs. The fact that pigs fatten apparently as well on diseased potatoes when cooked by steaming or boiling, as on sound ones, is certainly a very important mitigation of this dreaded calamity. There are several varieties of the potato, such as "yams," "lumpers," "mangel-wurzel potato," which, although unfit for human food, are much relished by cattle, and which, from their abundant produce, healthiness, and great fattening quality, are well deserving of being more generally cultivated for the purpose of being used in combination with turnips and other substances in the fattening of cattle. The turnip crop of recent years has been nearly as much diseased as the potato crop, and as one remedy against " fingers-and-toes" in the former is to let longer intervals of time intervene before their recurrence in the same field, and as it has been ascertained that an acre each of beans, potatoes, and turnips will produce more beef than three acres of turnips alone, it is worthy the consideration of those concerned whether it would not be prudent to substitute a crop of these coarser potatoes for a portion of their turnip crop on fields or parts of fields that have borne diseased turnips in previous rotations. Eight tons per acre is a good crop of potatoes.
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