Читать книгу The Grapes of New York - U. P. Hedrick - Страница 10

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The history of the viticulture of eastern United States shows that the regions in which grapes have been most largely grown in the past have come into prominence, had their day, and then suffered a decline. The reasons for the more or less temporary character of grape regions are becoming more and more apparent as our knowledge of grape-growing increases. The grape, more than most other domesticated plants, is profoundly influenced by climate, soil, cultural treatment, and insect and fungus pests. In any region in which the grape succeeds at all well, conditions are more favorable at the start of the industry than later; this is especially true as regards soils, and the insect and fungus pests. In a discussion of any phase of grape culture, in a broad sense, the conditions under which the fruit is grown must receive careful consideration. We therefore include in this chapter a discussion of the characters which most strongly influence grapes in vine, fruit and general adaptability; also a brief discussion of the regions in which native grapes have been successfully grown in America; and, more particularly, an account of the viticulture and the grape regions of New York.

In their wild state the various species of native grapes seem adapted to a great diversity of soils and conditions. But under successful cultivation varieties of the several species are confined to somewhat restricted regions and even localities. Often a grape variety will succeed on one shore of a lake or river and not on the other; on one slope of a hill but not another. It is difficult to point out the determinants of successful grape culture. Adaptability can be known positively in many cases only by trial; for neither conditions of soil, nor climate, nor lay of land determines with certainty the adaptability of a given locality. Oftentimes one variety of a species may not be successful while another is completely so. Many varieties reach perfection in one region or locality but not in another though the conditions may seem very similar. So great is the influence of local environment, oftentimes, that a variety grown in one locality might not be recognized as the same grape when produced under other conditions.

The chief natural factors which govern the distribution of varieties of grapes are: Latitude and altitude; temperature of air and soil; water supply; the chemical and physical properties of the soil; air currents; and insects and fungi.

Latitude and altitude very largely determine the annual temperature, the amount and intensity of sunlight, and the length of the growing season—all very important factors in growing grapes. Species and varieties of grapes are usually adapted to regions having about the same latitude; northern types do not succeed in the South nor the reverse. Length of season has more to do with the adaptation of grapes than the degree of heat or cold, for some southern sorts are hardy in vine in the North but the seasons in the northern latitude are not sufficiently long for the fruit to mature. On the other hand, northern varieties mature too quickly in the South and pass through maturity to decay with too great rapidity. The metes and bounds of latitude are often set aside in grape-growing by local modifications. Thus it often happens that valleys in regions not generally adapted to viticulture are so protected from cold winds, so open to sunshine, or are so free from fogs or frosts as to furnish ideal conditions for grape-growing.

Probably the chief factor in determining the adaptability of a region to grape culture is temperature. Each of the different species and varieties of grapes requires a certain amount of warmth for its best development and can endure but a certain degree of cold. The temperature of a region is chiefly determined by latitude, altitude and proximity to large bodies of water, though variations in the surface of the country are often important modifying agents of temperature and especially influence spring and fall frosts.

The grape does best in an equable temperature and does not thrive in regions where there is a great daily range. Regions and seasons in which the temperature is comparatively low in the growing months of May, June and July and high, with much sunshine, in the maturing months of August, September and October, produce the best grapes in the latitude of New York. An average of from 55° to 65° for the first named period and of from 65° to 75° for the second are ideal temperature conditions for the grape.

This fruit is very sensitive to moisture conditions. Not only must the total rainfall for the year be taken into consideration but its distribution throughout the seasons must be considered. The grape does best with comparatively little rainfall. When the rainfall is the least possible amount for a good growth of vine the grape crop will be the largest, of best quality and most free from fungi. Wet seasons, and especially wetness during the months of maturing, are disastrous to both quantity and quality of grapes. Thus, in New York it is not possible, with most varieties, to produce good grapes if the average is above six inches each for the three growing months and five inches each for the maturing months. It is far better for the crop that it be as low as four inches for the first named period and two inches for the second period.

Superfluous moisture in the soil favors too great a growth of vine, checks and weakens the root system, prevents proper setting of fruit, and favors fungi, but hinders the multiplication of phylloxera. In particular, a comparatively dry soil is desirable for grapes because of its influence on the development of the root system. In dry soils large root systems are developed in the search for the water that the plant must have. When intense droughts occur plants that have stood in damp soils have not sufficient roots to supply the necessary water to the aerial parts and the vines suffer in consequence. Some species and varieties are better fitted for withstanding an excess of moisture than others.

The soil exercises a great influence in determining the suitability of a region for viticulture. Several factors act as soil determinants: (1) Fertility; (2) physical characters; (3) soil heat. It is necessary to study each species, and even their varieties, to discover their powers of adaptation to different soils and it is possible to indicate here the good and bad qualities of soils only in the most general way. In the discussion of species and varieties the soil preferences of the different botanical and horticultural groups will be stated more fully.

Great fertility, as a natural characteristic, is not necessary in grape regions. Fertilizers, and especially the use of stable manures and cover crops, can be made to supply very largely a lack of fertility. Soils naturally too rich produce an overdevelopment of vine. Some species, as Vitis rupestris, grow naturally in very poor soils, the habitat of the latter being dry ravines and stony places having comparatively little organic matter. The varieties of Vitis rupestris promise well for stocks upon which to grow other varieties in certain soils. In Europe calcareous or limy soils are not considered well adapted to grape-growing, but in America we often find very good vineyards on such soils.

The physical character of a soil has more to do with the welfare of the grape than fertility. Sand and clay are the two distinct types of soils usually found in general agricultural regions. As one or the other predominates soils take their character. So far as growth alone is concerned these two types of soil do not influence the vines much differently, but the fruit in quantity and quality is greatly influenced by them. According as to whether sand or clay is in excess a soil is loose or compact, retains or gives up water, and is warm or cool. A compact soil is made so by an excess of clay or of very fine sand. Grapes require a light friable soil and compactness is often a serious defect. Usually species and varieties with large, thick roots are better adapted to compact soils than those with small root systems, probably because the strong roots have greater penetrating power than the weak ones. Lightness and permeability of the soil may be influenced by subsoiling and through the use of stable manure and cover crops, but a hard soil is generally so ill adapted to grape-growing that this fruit should not be planted on it.

The heat-retaining properties of a soil must always be taken into account in growing grapes. The great preference which many varieties of grapes show for sands, loams, shales and gravels, depends largely upon the greater amount of heat found in such soils. In northern regions it is especially needful that the soil furnish an abundance of bottom heat for the grape. The removal of an excess of moisture is helpful in regulating soil heat; and, other things being equal, a well-drained soil is warmest.

Grapes grow more or less well in any soil adapted to fruit-growing. It is not true, even, that the grape is more particular as to soils than other fruits. But the necessity of having great quantity and high quality of fruit in profitable viticulture makes it very necessary to take their preferences as to soil into strict account.

Air currents are of minor importance compared with the other factors discussed yet are worthy of attention. They are chiefly of importance in grape-growing in the suppression of fungi. It has long been noticed that in regions where there are strong currents of air the dreaded black-rot and the mildew are not nearly so harmful. Winds may be beneficial, too, when they bring warm air, when moisture laden, when they keep frosty air in motion, and possibly they have an effect on some small insects as the leaf-hopper. On the contrary they may be detrimental when too dry, strong or cold. Natural or artificial windbreaks may greatly modify the effects of wind currents though their value is usually overestimated as their benefits are often offset by the undesirable conditions caused.

Lastly, the prevalence or lack of insects and fungi in a region may decide its value for viticulture. In several instances flourishing viticultural industries have been destroyed in this country by insects or fungi, or both. In other regions the present supremacy of commercial grape-growing is almost wholly due to the fact that neither insects nor fungi are seriously troublesome. The advent of spraying and a better knowledge of the life histories of insects and fungi are lessening the importance of the parasite factor in determining the value of a region for grape-growing, but it is still of high importance.

We are now prepared to take up a discussion of the grape regions of New York.

The states in which the growing of American grapes takes the rank of an industry are, according to the census of 1900, in order of production: New York, Ohio, Pennsylvania, Michigan, Illinois, Indiana, Kansas, Missouri, Georgia and Oklahoma. The value of the product in the leading state was $2,763,711; in the last named state, $128,500. American viticulture, so far as native grapes are concerned, is almost wholly confined to twelve states. But viticultural interests are still further localized. In New York the industry is divided into four great regions, the Chautauqua district, the Central Lakes district, the Hudson district, and the Niagara district. In Pennsylvania and Ohio grape-growing is largely confined to the shores of Lake Erie; in Michigan to a small district about the towns of Lawton and Paw Paw; in Missouri, Hermann is the representative point for grape culture.