Читать книгу The Pears of New York - U. P. Hedrick - Страница 29

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Pears thrive in a great diversity of soils, provided, almost always, that there is depth for proper root-run. A few varieties may be grown in comparatively shallow soils, but most pears are deep-rooted. The common pear is rather averse to sand, gravels, and light soils in general, and does best in rather heavy loams, clays, and even in silts. Many varieties show preferences for the several types of loam and clay, and the commercial grower must see to it that the varieties he plants are suited in their particular soil preference. Hybrids between the common pear and the oriental pear—the Kieffer and its kin—grow well in much lighter soils than pure-bred sorts of the common pear, and, as a rule, find sands and gravels more to their liking than clays and heavy loams. Pears will stand rather more water in the soil than any other of their orchard associates, but a soil water-soaked for any great length of time in the growing season is a poor medium in which to grow pears. If, therefore, a soil is not sufficiently dry naturally it must be tile-drained.

Pear soils must be fertile. All varieties of this fruit refuse to produce good crops in soils lacking an abundance of the several chemical elements of plant nutrition. Even the light soils on which Kieffer, Garber, and Le Conte seem to do best must be well stored with plant-food. This means that good pear land is costly. Soils that grow good pears usually grow good farm crops. Pears planted in a poor soil do not live but linger. Who has not seen short-wooded, rough, malformed, dwarfed, starved trees which have come to their wretched condition because planted on land not fertile enough for this fruit? The land-skinner who grows grass in his orchard usually comes to grief quickly. Pears start best in a virgin soil from which the forest has not been long removed; on the other hand, they are often hard to start on senile soils even though they have been heavily fertilized. Plenty of humus seems to stimulate pears. There is a prejudice against soils too rich, some holding that on overly rich land the growth is soft and sappy and therefore a good medium for the multiplication of the blight bacteria. This is mostly prejudice, but certain it is that culture and fertility should not be so managed that the growth continues late, and the trees go into the winter soft and tender to cold.

Soils seem to have a profound influence on the flavor and texture of pears. In uncongenial soils the fruits are often so sour or astringent, dry or gritty, that the product is poor in quality; whereas the pears of the same variety in a soil to which it is suited are choicely good. A few varieties, as Bartlett, Clapp Favorite, and Seckel, grow well and produce fine fruit in a great diversity of soils, but most sorts do so much better in one soil than in another that it becomes a matter of prime importance in pear-growing to discover the particular adaptations of the varieties to be planted. To discover an ideal soil for a variety is about the highest desideratum in pear-growing.

Some varieties are made to grow in uncongenial soils by grafting them on stocks better adapted to the soil. Thus, on certain soils some pears grafted on quince stocks do better than on pear roots. This is a great field of future discovery and one in which discoveries are being made as experimenters try new stocks to secure greater resistance to blight. In all of this work, pear-growers must know not only how well the stock resists blight, but also how well the cion takes to the stock and the stock thrives on various soils.

The pear is easy to suit in matter of site for the orchard so far as lay of land is concerned. Altitude, exposure, slope, and local climate, all so important in choosing sites for the more tender peach, plum, and sweet cherry, need receive little consideration in planting the pear. A site somewhat higher than the surrounding country gives the two great advantages of soil drainage and air drainage. Good air drainage is a prime requisite with pears, as it helps to reduce the danger from frost, and neither pear-scab nor fire-blight are as virulent as on trees planted on sites where there is little movement of air. Rolling land, so often recommended for all fruits, seems not to be essential for pears, as many splendid orchards of this fruit are on flat lands, which, however, usually have an elevation above the surrounding country on one or more boundaries. The influence of large bodies of water, so favorable to the peach, is not as necessary with the pear, although the best pear regions in the State are near the Great Lakes, the Finger Lakes, or along the Hudson. There are no successful pear-orchards in the State surrounded by higher land. Frosts, freezes, pear-blight, and fungi would soon play havoc with pear-trees in such a situation.

The shelter of hills, forests, or of apple-orchards, provided they do not shade the pear-orchard too much, may be a valuable adjunct to a site. Such shelter, however, is desirable only when so situated as to protect against unseasonable winds and storms. Tree and fruit suffer greatly when loaded branches are whipped about by strong winds. The advantages of artificial windbreaks, whether of evergreen or deciduous trees, are usually more than offset by disadvantages. The direction in which land slopes is greatly over-emphasized by horticultural writers if orchards in New York are considered. The only important aspect of exposure for pears in this State is that the land slope toward the water when near a large body of water that the orchard may secure in full the effects that come from planting trees near the water.

Economic considerations are becoming more and more important in choosing sites for all fruits in New York. Transportation facilities, including good roads, markets, labor, and packing and selling organizations are now more important in the pear regions of the State than the natural determinants of soil and climate, since these are so favorable in any of the fruit regions in which pears are largely grown. Natural advantages are more common than man-made ones, and the pear may be grown on vast areas of New York lands so far as climate and soil are concerned, but which are wholly unsuited because the economic factors are unfavorable. Sites for pear-orchards should be sought for in localities where there are pears enough grown for a central packing association; near a shipping center where the haul is short and over good roads; the freight service should be prompt, regular, and efficient, with low freight and good refrigerator service; labor should be abundant and not too expensive; and the markets should be several and so located that they are not controlled by growers in regions more advantageously situated.

The pear-grower is becoming more and more concerned with the kind of stock upon which his trees are grafted. One or more of several objects is sought in working a pear on roots other than its own. The stock may be chosen, and most often is, with the single purpose in view of perpetuating a variety; it may be selected to dwarf or magnify the size of the cion; very often the stock is better adapted to the soil than the cion would be on its own roots; the quality of the fruit is sometimes improved by the stock; lastly, some stocks are much more resistant to fire-blight than others. It is this last character of the stock that is now receiving most attention. Stock and cion are united either by budding or grafting, with budding coming more and more in use. More than with any other fruit, double-working is used in propagating pears. For example, the quince stock is often preferred to a pear stock. But some varieties of pears do not unite well with the quince, in which case a sort which makes a good union with the quince is first budded or grafted on the stock, and when this cion has grown to sufficient size, it is top-worked to the desired variety. According to the size of the mature plant, pear-trees are designated as dwarfs and standards, the difference in size being brought about by the stock. Dwarf trees are usually grown on quince stocks; standards, on pear stocks.

Dwarfing pear-trees is an old practice, having been in use in Europe at least 300 years. During this time the use of quince stocks to dwarf the pear has been a common practice in France and England. For a century, dwarfing the pear by growing it on the quince has been common in America. Dwarfing is recommended to secure several effects. Dwarf trees are more manageable than standard trees when the orchard area is small; dwarfing stocks are shallow rooted, and dwarfs, as a rule, do not need a soil so deep as do standard trees; pears grown on quince stocks are often larger, handsomer, and better in flavor and texture than those grown as standards; the trees come in bearing earlier. Dwarf pears, never very common on this continent, are not planted as much now as they were some years ago. At one time, orchards of these dwarfs were a familiar sight in New York. A dwarf orchard and even a dwarf tree is now seldom seen. The faults that have driven them out of New York are: The stocks used in dwarfing are not uniform, consequently the trees vary in vigor, health, habit of growth, and in time of maturity; nurserymen find that the stocks vary greatly in ease of propagation either from cuttings or layers; the quince stocks are of several varieties, difficult and expensive to obtain and, therefore, the orchard trees are expensive; dwarf trees require much more care in pruning, training, and cultivation than do standard trees; the cost of producing pears in a dwarf orchard is greater than in a plantation of standard trees, and the fruit does not command a much higher price; dwarf trees are commonly rated as less hardy than standard trees and are much shorter-lived; left to themselves, or if planted too deep, the cions take root and the trees are but half dwarf. Some of the objections to dwarf trees could be done away with by obtaining a variety of the quince which would dwarf the pear satisfactorily, which could be grown easily from cuttings or layers, and upon which most pears could be easily worked. A quince of this description is not in sight.

There is great difference of opinion among growers as to what varieties may be successfully grown on quince stocks. Probably all will agree that the following, few indeed, are the best dwarfs in America: Beurré d’Anjou, Duchesse d’Angoulême, Howell, Lawrence, Louise Bonne de Jersey, Elizabeth, and White Doyenné. All other sorts, if to be grown on dwarfs, grow better when double worked.

Almost all of the pears grown in America, as has been said, are standard trees. The stocks for these standard pears are nearly all imported from Europe under the name French stocks, although on the Pacific slope seedlings of oriental species are being used more and more. The French stocks are seedlings of vigorous forms of the common pear, P. communis. Efforts to grow stocks of this species in America usually fail because leaf-blight is so destructive as to make their culture unprofitable. Leaf-blight can be controlled by spraying, but other deterrents, as high price of labor and losses from dry summers, added to the cost of spraying, make American-grown stocks expensive. Stocks raised in this country are usually seedlings from imported seed. Seedlings of the Sand pear, P. serotina, and its hybrids have been tried extensively in the South and West to obtain cheap stocks more resistant to pear-blight than the French stock, but they do not seem to be much more resistant to blight, and many of the best varieties do not take on these stocks, so that they are generally considered a failure.

New types of stocks are needed badly. The ideal stock must be vigorous and hardy; fairly immune to leaf-blight and fire-blight; it must come from a species which seeds freely, and the seedlings from which are uniform; this ideal stock must be adapted to all pear-growing regions in the country; a large percentage of the seedlings must make first-class stocks; the budding season must be long; congeniality with all cultivated varieties must be great or very nearly perfect; the consort of stock and cion must make a long-lived tree.

Quince stocks are obtained from cuttings or mound-layers. Layering is considered the better method of the two. Stocks from the oriental hybrids, of the Kieffer and Le Conte type, are often grown from cuttings in the South. These are made in the spring from mature wood of the preceding year’s growth, and are treated much as are grape and currant cuttings. Long cuttings, a foot in length if possible, should be used. These stocks are of little value for varieties of the common pear, but are better than French stocks for the oriental hybrids, since these, in the South at least, usually overgrow French stocks. Own-rooted trees of these oriental hybrids are often grown from cuttings.

While of doubtful utility, stocks from other genera may be used for the pear. Some of the thorns are occasionally used as dwarfing stocks. The mountain ash is sometimes used to adapt pears to light sandy soils. Occasionally one hears of pears grafted on sorbus. The pear on the apple is short-lived, but old apple-trees top-worked to pears sometimes give abundant crops for a few years. Apple roots may be used as a nurse for pear cions. To be successful, the pear cion should be long, when, if grafted on short apple-roots and set deeply, the pear sends out roots and eventually becomes own-rooted.