Читать книгу The Pears of New York - U. P. Hedrick - Страница 30

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Perhaps no tree-fruit is more exacting in care than the pear. Young trees, in particular, must be well cared for and more or less coddled if any factor in environment is adverse. Almost any young orchard of this fruit becomes moribund if the owner settles down to self-satisfied complacency. As the trees come into full bearing, the several items of culture need not be so intensive. A perfect pear-orchard is about the consummation of good fruit-growing. But a perfect orchard of this fruit is seldom to be found, for, sooner or later, blight is certain to take its toll. Because of blight, the culture of no other fruit is attended with more frequent or keener disappointments. Today a man may walk in his orchard with adoration, as an artist walks in a beautiful landscape. Tomorrow, blight may blast the fairest trees. Pear-growing, thus, becomes a good deal of a gamble, and the boundaries within which a fruit-grower’s ambitions must be confined as to acreage must be more closely drawn than with other fruits. In most pear regions, the risks are too great to venture all in the culture of this fruit.

It is an uphill task to grow pears on land not well fitted before planting. A young pear-tree is about the least self-assertive of any of the tree-fruits. For the first year or two young pears seem to have almost no internal push, and are unable to get much of a start out of any but land in the best of tilth. A bare, stony, starved soil is no place for a young pear. The ground should be well tilled almost or quite to the depth the trees are to be planted, otherwise the roots seek the upper layers of earth where there is least resistance and food is most available. If the drainage is faulty, subsequent treatment is well-nigh useless. Sometimes retentive soils in which drainage is good most of the year but slow at planting time may be brought into condition by plowing a back-furrow along the line of each row in the direction of surface drainage to carry away the surface water. Under no circumstances should a tree be planted in a hole in which water is liable to stand about the roots. If possible, the land should be prepared a year in advance by putting in a hoed crop, after which it should be plowed deeply in the fall and pulverized well in the spring, and the trees planted as promptly as possible.

Land suitable for growing pears does not need to be fertilized for young trees. It is not too much to say that land which will not grow good wheat or corn is hardly fit for pears, although lighter soils fertilized as the trees come in bearing grow some varieties very well; but even on these the young trees will start as well without as with fertilizers. Commercial fertilizers, at least, are not wanted by young trees. Stable manure, usually priceless in orchard regions, often puts an atmosphere in an orchard not to be had by any other means, chiefly, probably, because it helps to put the land in good tilth rather than because of the plant food supplied.

Present practices in the use of fertilizers for mature pear-trees are very diverse. Until experiments in fertilizing pears are carefully carried out, the pear-grower may well follow the practices of apple-growers, since a considerable number of long-time experiments have thrown light on the fertilizer requirements of apples in the several great fruit regions of the country. The pear, however, requires a richer soil than the apple; but, on the other hand, it is pretty well agreed that the blight bacterium finds readier entrance and a better medium in which to grow in the soft wood of a luxuriant growth than in the more compact wood of slow growths. Whatever fertilizer is used should be applied early to promote early growth and so permit thorough ripening of wood well in advance of severe cold. Many growers maintain that blight is less virulent in orchards laid down to grass. It is doubtful if this is true and if true the produce is so scant and the pears so small that an orchard grown in grass is about as often a liability as an asset. When the pear is set in grass, however, nitrate of soda applied very early in the season in liberal amounts is a necessary adjunct to the grass-mulch. In any pear orchard, when the foliage is off color, small, sparse, or hangs limp, nitrate of soda is a sovereign rejuvenator.

This discussion may be closed with advice as to how one may know when his trees need fertilizers. If the trees are vigorous, bearing well, the fruits of proper size, the foliage a luxuriant green, the growth plump, the buds turgid, he may well assume that his trees need no additional plant-food. If the trees are not in the condition of well-being indicated, one ought to be well assured that drainage, tillage, and health are as they should be before applying expensive and uncertain fertilizers. Nothing is more satisfactory than making sure that one is not putting chemicals in the ground for nothing in the use of fertilizers. A simple experiment to obtain positive evidence as to whether a pear-orchard needs fertilizers is easily carried on and gives assurance where before there was doubt.

The following is an example of such an experiment: (1) Acid phosphate to give about 50 pounds of phosphoric acid to the acre applied to one plat; (2) phosphate as above and muriate of potash to give 100 pounds of potash to the acre on another plat; (3) phosphate and muriate as above and nitrate of soda and dried blood to give 50 pounds of nitrogen per acre on a third plat; (4) six tons of stable manure on a fourth plat; and (5) one plat left unfertilized as a check.

Planting practices vary so greatly from place to place and from time to time, and each method at the place and time seems so justifiable, that one can hardly advocate particular methods and can only state what they are. Thus, pears have been set in accordance with all of several planting plans, and at distances ranging from sixteen to twenty-five feet apart. At present, pear-orchards are usually laid out in meridians and parallels at intervals of eighteen and twenty feet; when the first distance is used, one hundred and thirty-four trees are planted to the acre; if the second, one hundred and eight trees. It is patent to the eye of every passer-by that these distances are more often too small than too great. Certainly on rich soils and with varieties the trees of which are spreading, the distance might often better be put at twenty-two or twenty-four feet. A poorly-colored pear is usually a poorly-flavored pear; and color and flavor are largely dependent on sunshine and air which are hardly to be had in closely-planted trees. Perfect alignment is imperative for convenience in working and pride of appearance. Dwarf trees in New York should be set at least fifteen feet apart each way, one hundred and ninety-three trees to the acre, although it is a common practice to set them closer.

Until recently one of the discouragements in pear-growing was the failure of fruit to set, even though the trees bore an abundance of blossoms. The discovery that failure was often due to self-sterility in a variety, and that it was necessary to set another variety near-by to furnish pollen to fertilize the self-sterile blossoms has removed much of the uncertainty in growing pears. We now know that self-sterility has a most important economic aspect in the planting of pears. Some of the varieties most profitable when planted to secure cross-pollination, are so unfruitful as to be quite unprofitable when a tree stands alone or when the variety is set in a solid block with no other sort near. Under most conditions Bartlett and Kieffer, the mainstays of American pear-culture, both need pollen from another variety to insure a full set of fruit. Under some conditions both may be sufficiently self-fertile. From these two statements it is seen that self-sterility is not a constant factor in a variety.

Self-sterility and self-fertility are greatly influenced by the condition under which a variety is grown. Thus, a variety is often self-sterile in one locality and not in another. Occasionally Bartlett, usually nearly or quite self-sterile, and other varieties as well, set fruit one season and not the next. All pears, the Bartlett in particular, seem to have a greater degree of self-sterility in eastern pear regions than on the Pacific slope. In general, the better the adaptation of a variety to its environment the better it sets fruit with its own pollen. It is obvious, therefore, that it is not possible to give lists of self-sterile and self-fertile varieties. Such lists can be made out only for regions and localities. Some varieties, however, more often fail to set fruit because of self-sterility than others. Among standard pears, Bartlett, Beurré d’Anjou, Beurré Clairgeau, Clapp Favorite, Howell, Kieffer, Lawrence, Sheldon, and Winter Nelis appear to be most often self-sterile. Beurré Bosc, Flemish Beauty, and Seckel are usually self-fertile.

A self-sterile variety usually sets fruit when another variety is at hand to supply pollen. Several considerations determine the selection of varieties to interplant. Thus, the two varieties must blossom at the same time if cross-pollination is to be effective. The table on pages 88 to 90 shows the sorts that bloom at the same time, or nearly enough so to make cross-pollination possible. Under normal conditions, the blooming time of varieties overlaps sufficiently for cross-pollination excepting those that bloom very early and very late. If the table is used for regions much to the north or to the south of this Station, allowance must be made for a shorter blooming period the farther north; a longer one the farther south. That varieties of pears have sexual affinities is another consideration that merits some attention. That is, one variety will fertilize another sort very well, while pollen from a third may not be at all acceptable. “Affinities” can be determined only by hand crossing. Probably the importance of affinities is over-rated. The distance between varieties set for cross-pollination must not be too great—not more than two or three rows apart. For convenience in harvesting, varieties should be selected in relation to ripening. Only commercial varieties should be interplanted, as the wastage is too great if comparatively worthless sorts are set to fertilize a standard commercial variety.

Some disadvantages attend the setting of mixed orchards of pears, and these must be weighed and overcome as far as possible. There are many current statements to the effect that all varieties, whether self-sterile or self-fertile, are more fruitful and produce better fruit with foreign pollen than with their own. To old pear-growers, this seems to be putting it rather strong, but the statements come from accurate experimenters and observers and should have consideration. Cross-pollination, be it remembered, is not a cure-all for failures to set fruit. Unseasonable weather, lack of vitality in trees, various fungi, and no doubt other agencies, may be the cause of unfruitfulness.

As to commercial varieties, the tale is soon told. Only a half-dozen sorts are generally planted in New York orchards. These, about in order of importance, are: Bartlett, Kieffer, Seckel, Beurré Bosc, Beurré d’Anjou, and Winter Nelis. To this short list may be added the following grown more or less for local markets: Clapp Favorite, Sheldon, Beurré Clairgeau, Lawrence, Howell, Tyson, and Mount Vernon. A list for the home orchard should include all of these and many more to be chosen from the major varieties described in Chapter IV. The pear flora of the country changes very slowly, and there are now almost no new sorts on general probation in the country.

Perhaps with no other tree-fruits is it more important to begin with good trees, as even with the best it is often difficult to get a good start toward a pear-orchard. Black-heart, caused by winter-killing, is a sign that must be heeded, and a tree badly blackened in its pith, especially if the surrounding wood is discolored, should be discarded. Crown-gall on tap roots affects the tree deleteriously. Trees marked by hail or insects are often worthless. Other marks that commend or condemn trees are: A short stocky plant is better than a tall spindling one. A tree with many branches is better than one with few branches. The roots should be much branched rather than sparsely branched. A tree with smooth, bright bark is better than one with rough, dull bark. Both trunk and branches should be plump and show no signs of shrivelling. A poor pear-tree in the nursery seldom makes a good tree in the orchard. There is great variation in varieties as the trees come from the nursery, a fact to be considered. In New York, two-year-old trees are best.

A good deal of the success that attends the culture of the pear depends on properly setting the young trees and the right care of the young plants. It is superfluous to discuss these operations in detail, but a statement as to proper setting and care will serve as reminders. In this State, pear-trees should always be set in the spring. A young pear-tree should be set in the soil about as deep as it stood in the nursery; in light soils the roots might well be planted a little deeper, and in heavy soils not quite so deep. The soil must be packed firmly about the roots—best done by tramping. Watering is necessary only when the land is parched with drought. When necessary, water should be used liberally. Puddling the roots by dipping them in thin mud before planting serves very well for watering. The surface soil should always be left loose. Rank manure about the roots of young trees is plant infanticide. During the tender nonage of the young pear, cultivation should be intensive; insects and fungi should be kept off; and plants that refuse to grow well must be marked for discarding.

A catch-crop grown between the rows of pears is a profitable adjunct to the pear-orchard for the first four or five years. Few indeed are the pear-orchards in New York that cannot be made to sustain themselves for the first few years by inter-cropping. The crops should be hoed crops, such as potatoes, cabbage, beans, tomatoes, and nearly all crops in demand at the canneries. Along the Hudson, small-fruits are often planted in young pear-orchards, but in Western New York these are not looked upon with favor. Grass and grain are deadly in a young pear-orchard, and no right-minded man would plant them there. This brings us to cultivation.

Cultivation should be the rule; sod mulch, the exception, in growing pears in New York. After pear-trees come into bearing they may be made to produce crops if kept in sod. The grass in sodded orchards should be kept closely mown to form a mulch about the trees. Commercial fertilizers as well as mulch are needed in sodded orchards, and of the several chemical fertilizers nitrogen is most requisite. The man who grows pears in sod must not expect as much fruit, as the crop is lessened in both number and size of the pears. On the other hand, the pears may be better colored, and the trees may be freer from blight.

Tillage is begun in the spring by plowing the land. This operation is followed by cultivation with smoothing-harrow, weeder, or cultivator. There are several reliable guides to tell when and how often a pear-orchard should be cultivated. When the soil becomes dry it should be tilled. A heavy rain should always be followed by the cultivator to prevent the formation of a crust on the surface. At this time, he tills twice who tills quickly. Cultivate when there are clods to be pulverized. Usually a pear-orchard should be cultivated once in two or three weeks until time to sow the cover-crop in midsummer. The depth to till is governed by the season and the nature of the soil. Heavy soils need deep stirring; light soils, shallow stirring. Till moist soils deeply; dry soils, lightly. The time to stop tillage depends on the soil, the climate, and the season. The fruit should be nearly full sized when tillage is stopped and the cover-crop sown.

The cover-crop seed is covered the last time the cultivator goes over the orchard. Clover, vetch, cow-horn turnip, rape, oats, rye, and buckwheat are all used as cover-crops in this State. Combination crops are not popular because of too great cost of seed. The quantity of seed sown is the same as when the crops are grown as farm crops. The crops must be changed from time to time in whatever rotation seems most suitable for the soil. The weather-map must be watched at sowing time to make sure of a moist seed-bed. Whatever the crop, it should be plowed under in the fall or early spring, and under no circumstances should it stand late in the spring to rob the trees of food and moisture. In moist, hot seasons, the cover-crop should be sown earlier than in seasons of slow growth, when, possibly, it acts as a deterrent to blight, and certainly makes more certain thorough ripening of the new wood.

The double nature of pruning must be kept in mind whenever a pruning tool is taken in the pear-orchard. Fruit-trees are pruned to increase the quantity and quality of the crop—this is pruning proper; and to give the trees such form that they are easily managed in the orchard—this is training. Pruning tools are used first when the trees are set, and they should be used every year thereafter as long as the tree lives. The pruning at setting time is particularly important with the pear, since newly set pears are slow and uncertain in starting, and linger in growth for a year or two after going into the orchard. The pruning is much the same as with other trees, but must be done with a little greater care.

The top of the young plant must be pruned to enable the injured root-system to supply the remaining branches with water. The less the roots are injured, the less the top need be cut. Some cut back all of the branches; some remove whole branches and do not head back those that remain. The latter is the better plan for this reason: The top buds on branches are largest and develop first, and the newly set tree will grow best if it develops a large leaf-surface before hot dry weather sets in. Young trees usually have surplus branches; remove those not needed, leaving three, four, or rarely five to form the framework of the tree. A pear so pruned will start growth and acquire vigor more quickly than if all branches are cut back.

A choice must be made when planting as to whether the tree is to be low- or high-headed. The habit of growth of varieties differs so greatly that there can be no rule to determine how high the head of a tree should be started. One can generalize to this extent: The heads of varieties with spreading tops should be started higher than those having an upright or pyramidal top. Without question, the choice should be for a low-headed pear-tree. The trunks of pear-trees suffer terribly from blight and sun-scald. The less trunk and the more it is shaded by branches, the less the tree suffers from these two troubles. Also, low trees are more easily sprayed and pruned; the crop is more easily thinned and harvested; crop and tree are less subject to injury by frost; the top is more quickly formed; and a low-headed tree bears fruit soonest. By low-headed is meant a distance from the ground to the first limb of two feet.

Two shapes of tops are open to choice—the open-centered and the close-centered. In the open-centered, or vase-form top, the tree consists of a short trunk, surmounted by four or five main branches ascending obliquely. In the close-centered top, the trunk is continued above the lower branches and forms the center of the tree. The close-centered pear-tree produces more fruit and is most easily kept to its shape. No doubt it is best for most varieties. The open-centered tree, with its framework of several main branches, has the advantage when trees are attacked by blight, since if one or two branches are destroyed by the disease a part of the tree may still be saved. The head should never be formed by two central leaders forming a crotch, as the trunk is liable to split and ruin the tree.

For several years after planting, the pear needs to be pruned only to train the tree to the height of head determined upon and to form the top. Exceptions are the sorts which produce few branches and thus form straggling heads. This defect is overcome by cutting back some of the branches in the spring, an operation which increases the number of branches. A few other sorts, as Winter Nelis and White Doyenné, have drooping, twisting, wayward branches which can be trained into manageable shape only by cutting back or tying the branches in place. Pear-growers as a rule prune young trees too much. Over-pruning increases the growth of wood and leaf too greatly, and thus delays the fruiting of the plant. A good deal might be said about the use and abuse of heading-in pears—that is, cutting back the terminal growths from year to year. Dwarf pears must be headed-in severely to keep the trees down, but standard trees should be headed-in only to make the tops thicker and broader—a desirable procedure with some varieties.

Old trees often need to be pruned to increase their vigor. Such pruning is often spoken of as pruning for wood. When the tops of pear-trees have dead and dying wood, when the seasonal growth is short and slender, when the crops are small and the pears lack size, or when trees are weakened by disease, a healthy condition may oftentimes be restored by severely cutting back some branches and wholly removing others. In such pruning the following rules ought to be observed:

Weak-growing varieties are pruned heavily; strong-growing kinds, lightly.

Varieties which branch freely need little pruning; those having few and unbranching limbs should be pruned closely.

In cool, damp climates, trees produce much wood and need little pruning; in hot dry climates, growth is scant and trees need much pruning.

Rich, deep soils favor growth; trees in such soils should be pruned lightly. In light or shallow soils, trees produce few and short shoots; the pruning of trees on such soils should be severe.

A good deal is said about pruning for fruit. It is doubtful, however, whether unfruitful pear-trees can be made more fruitful by the pruning recommended for this purpose. When barrenness is caused by the production of wood and foliage at the expense of fruit-buds, as possibly sometimes happens, summer-pruning may check the over-production of growth and cause flower-buds to form. There seems to be no definite experiments to prove this theory in America, nor do pear-growers generally practice this kind of pruning which has been preached so long and so often. To follow the rules in this operation, summer-pruning should be done when the growth for the season has nearly ceased. If done earlier, the shoots cut back start again and the pruning has been useless. If done too late, there is too little time for the production of fruit-buds. In the unequable climate of this country it is most difficult to know when to prune in the summer to meet the requirements of the theory urged so strongly by European pomologists. A weighty objection to summer-pruning in America is that the wounds might and probably would become centers of infection for blight.

There is no attempt to give a full discussion of pruning in this text. Such details as making the cut, covering the wounds, pruning paraphernalia, filling cavities and the amount to prune, belong to texts on pruning. Perhaps two minor details important in growing pears should be mentioned. Suckers or water-sprouts form so freely on branches of pears that they often seriously devitalize the tree, and usually are centers of blight. They should therefore be removed promptly whenever and wherever found. The time to prune the pear is important. If the work is done too early in the winter, injury may result to the tissues near the wound from cold or from checking. If done late in the spring when sap is flowing, the wound becomes wet and sticky and is a suitable place for the growth of fungi and the blight bacterium.

The pear is as easily grafted as any other pome, and the operation is more certain and more often desirable than with any of the stone-fruits. Almost any method of grafting used with orchard fruits is successful with the pear. But the pear is not often grafted in this State after the tree has been set in the orchard. The great objection is that the vigorous growth made by grafts is nearly always nipped by blight. Possibly the lack of affinity between different varieties is more pronounced than with other pomes. The common European varieties cannot be inter-worked without experimental knowledge of how one variety will grow on another, and it is almost impossible to intergraft common varieties with the oriental hybrids. The temptation is strong in this State to graft such sorts as Bartlett and Seckel on Kieffer. This combination is seldom successful; nor, as a rule, can other European pears be grafted on Kieffer, although some growers have succeeded fairly well in growing Seckel on Kieffer.

Thinning the fruit is not a common practice in pear-growing in this State. There is no doubt but that much might be done to improve pears in both size and quality by thinning, for be it remembered that large size of fruit and high quality are usually correlated in pears. Thinning often saves the vigor of the tree, and it is often good orchard management to destroy insect- or disease-infected fruit by thinning. The objection is high cost. Most growers, however, find that it pays to thin. Thinning is usually done as soon as possible after the June drop. It is most difficult to tell, when thinning, what will prove superfluity at harvest. A skilled grower adjusts the size of the crop to the variety, the vigor of the tree, fertility and moisture in the ground, the season, and insects and fungi. Thinning should begin in the winter with the removal of what seem to be superfluous branches, for even at this time fruit-prospects for the ensuing season are fore-shadowed.