Manual of American Grape-Growing Part 8

In an experiment being conducted by the New York Agricultural Experiment Station, grapes do not give a very appreciable response to cover-crops in yield of fruit or growth of vine.[9] There seem to be no other experiments to confirm the results at the New York Station, and grape-growers nowhere have used cover-crops very generally for the betterment of their vineyards. There is doubt, therefore, as to whether grapes will respond profitably to the annual use of cover-crops in yield of fruit, which, of course, is the ultimate test of the value of cover-crops, but a test hard to apply unless the experiment runs a great number of years.

Leaving out the doubtful value of cover-crops in increasing the supply of plant-food and thereby producing an increase in yield, there are at least three ways in which cover-crops are valuable in the vineyard.

Thus, it is patent to all who have tried cover-crops in the vineyard that the land is in much better tilth and more easily worked when some green crop is turned under in fall or spring; it is not unreasonable to a.s.sume, though it is impossible to secure reliable experimental data to confirm the belief, that cover-crops protect the roots of grapes from winter-killing; certainly it may be expected that a cover-crop sowed in midsummer will cause grapes to mature their wood earlier and more thoroughly so that the vines go into the winter in better condition. The only objection to be raised against cover-crops in the vineyard is that pickers, mostly women, object to the cover-crop when wet with rain or dew and usually choose to pick in vineyards having no such crop. This seemingly insignificant factor often gives the grape-grower who sows cover-crops much trouble in harvest time.

Several cover-crops may be planted in vineyards as clover, vetch, oats, barley, cow-horn turnip, rape, rye and buckwheat. Combinations of these usually make the seed too costly or the trouble of sowing too great. Yet some combinations of a leguminous and non-leguminous crop would seem to make the best green crop for the grape. Thus, a bushel of oats or barley plus ten pounds of clover or twenty pounds of winter vetch, a combination often used in orchards, should prove satisfactory in the vineyard. Or, doubling the amount of seed for each, these crops could be alternated, with a change in the rotation every four or six years, with cow-horn turnip or rape. Turnip and rape require at least three pounds of seed to the acre.

The cover-crop is sown in midsummer, about the first of August in northern lat.i.tudes, and should be plowed under in the fall or early spring. Under no circ.u.mstances should the green crop be permitted to stand in the vineyard late in the spring to rob the vines of food and moisture. The weather map must be watched at sowing time to make sure of a moist seed-bed. Plate III ill.u.s.trates two vineyards with well-grown cover-crops.

TILLAGE

Grape-growers are not in the fog that befuddles growers of tree-fruits in regard to tillage. He is a sloven, indeed, who permits his vines to stand a season in unbroken ground, and there are no growers who recommend sod or any of the modified sod-mulches for the grape.

Tillage is difficult in hilly regions and the operation is often neglected in hillside vineyards, as in the Central Lakes region of New York, but even here some sort of tillage is universal. The skip of a single season in tilling stunts the vines, and two or three skips in successive seasons ruin a vineyard. No one complains that grapes suffer from over-tilling as one frequently hears of tree-fruits. There is no tonic for the grape that compares with cultivation when the leaves lack color and hang limp and the vine has an indefinable air of depression; and there is nothing better than cultivation to rouse latent vigor in a scorching summer, or when drought lays heavy on the land.

_Tillage tools._

The tools to be used in tilling grapes vary with the topography of the vineyard, the kind of soil and the preferences of the vineyardist. The best tool is the one with which the ground can be well fitted at least expense. Good work in the vineyard requires at least two plows, a single-horse and a two-horse plow. The latter, except on very hilly land, should be a gang-plow. For commercial vineyards of any considerable size, several cultivators are necessary for different seasons and conditions of the soil. Thus, every vineyard should have a spring-tooth and a disc harrow, one of the several types of weeders, a one-horse and a sulky cultivator. If weeds abound, it is necessary to have some cutting tool, or an attachment to one of the cultivators, to slide over the ground and cut off large weeds. Another indispensable tool in a large vineyard is a one-horse grape-hoe, to supplement the work of which there must be heavy hand-hoes. Very often the surface soil must be pulverized, and a clod-crusher, roller or a float becomes a necessity. A full complement of bright, sharp tools at the command of the grape-grower goes far toward success in his business.

_Tillage methods._

There are several reliable guides indicating when the vineyard needs to be tilled. The vineyardist who is but a casual observer of the relation of vineyard operations to the life events and the welfare of his vines will take the crop of weeds as his guide. It is, of course, necessary to keep down the weeds, but the man who waits until weeds force him to till will make a poor showing in his vineyard. The amount of moisture in the soil is a better guide. The chief function of tillage is to save moisture by checking evaporation and to put the soil in such condition that its water-holding capacity is increased.

The physical condition of the land is another guide. Tilling when the soil needs pulverizing furnishes a greater feeding surface for the roots.

Tillage begins with plowing in early spring. Whether provided with a cover-crop to be turned under or hard and bare, the land must be broken each spring with the plow. Plowing is best done by running a single furrow with a one-horse plow up to or away from the vines as occasion calls and then following with a two-horse or a gang-plow.

Some growers use a disc harrow instead of the plow to break the land in the spring, but this is a doubtful procedure in most vineyards and is impossible when a heavy green-crop covers the land. Tillage with harrow, cultivator, weeder or roller then proceeds at such intervals as conditions demand, seldom less than once a fortnight, until time to sow the cover-crop in midsummer. About the time grapes blossom, the grape-hoe should be used to level down the furrow turned up to the vines in the spring plowing. Tillage should always follow a heavy rain to prevent the formation of a soil crust, this being a time when he who tills quickly tills twice. The number of times a vineyard should be tilled depends on the soil and the season. Ten times over with the cultivator in one vineyard or season may not be as effective as _five_ times in another vineyard or another season. In some regions, as in New York, the grower is so often at the mercy of wet weather in early spring that the plowing is best done in the fall, and spring operations must then open with harrowing with some tool that will break the land thoroughly.

The depth to till is governed by the nature of the soil and the season. Heavy soils need deep tilling; light soils, shallow tilling; in wet weather, till deeply; in dry weather, lightly. Grape roots are well down in the soil and there is little danger of injuring them in deep tillage. The depth of plowing and cultivating should be varied somewhat from season to season to avoid the formation of a plow-sole.

In some regions plowing and cultivating may be made a means of combating insects and fungi, and this regulates the depth of tillage.

Thus, in the Chautauqua grape-belt of western New York, the pupa of the root-worm, a scourge of the grape in this region, is thrown out and destroyed by the grape-hoe just as it is about ready to emerge as an adult to lay its eggs on the vines. In all regions, leaves and mummied grapes bearing countless myriads of spores of the mildews, black-rot and other fungi are interned by the plow and cannot scatter disease.

The time in the season to stop tillage depends on the locality, the season and the variety. It is a good rule to cease cultivation a few weeks before the grapes attain full size and begin to color, for by this time they will have weighted down the vines so that fruit and foliage will be in the way of the cultivator. In the North, cultivation ceases in the ordinary season about the first of August, earlier the farther south. Rank-growing sorts, as Concord or Clinton, do not need to be cultivated as late as those of smaller growth and scantier foliage, as Delaware or Diamond. The cover-crop seed is covered the last time over with the cultivator. Plate IV shows a well-tilled vineyard of Concords.

IRRIGATION

The grape, as a rule, withstands drought very well, several species growing wild on the desert's edge. Even in the semi-arid regions of the far West, where other fruits must always be irrigated, the grape often grows well without artificial watering. Irrigation is practiced in vineyards in the United States only on the Pacific slope and here the practice is not as general as with other fruit crops. Whether the grape shall be grown under irrigation or not is a local and often an individual question answered with regard to several conditions; as the local rainfall, the depth and character of the soil, the cost of water and ease of irrigation. These conditions are all correlated and make about the most complex and difficult problem the growers of grapes in semi-arid regions have to solve. As long, however, as the grape-grower can grow fairly vigorous vines and harvest a fairly bountiful crop by natural rainfall, he should not irrigate; for, even though the crop offsets the cost, there are several objections to growing grapes under irrigation. The vines are subject to more diseases and physiological troubles; the fruit is said to lack aroma and flavor; grapes grown on irrigated land do not stand shipment well, the unduly inflated grapes often bursting; wine-makers do not like irrigated grapes as well as those from non-irrigated lands; and watery grapes from irrigated lands make inferior raisins. It is maintained, however, with a show of reason, that grapes suffer in irrigated vineyards in the ways set forth only when the vines are over-or improperly irrigated.

[Ill.u.s.tration: PLATE VII.--Barry (2/5). Delaware (2/5).]

CHAPTER VI

FERTILIZERS FOR GRAPES

As regards fertilizers, the grape-grower has much to learn and in learning he must approach the problem with humility of mind. For in his experimenting, which is the best way to learn, he will no sooner arrive at what seems to be a certain conclusion, than another season's results or the yields in an adjoining vineyard will upset the findings of past seasons and those obtained in other places. Unfortunately, there is little real knowledge to be obtained on the subject, for grape-growers have not yet broken away from time-worn dictums in regard to fertilizers and still follow recommendations drawn from work with truck and field crops. This is excused by the fact that there have been almost no comprehensive experiments in the country with fertilizers for grapes.

No fallacies die harder than the p.r.o.nouncements of chemists a generation ago that fertilizing consists in putting in the soil approximately that which the plants take out; and that the chemical composition of the crop affords the necessary guide to fertilizing.

These two theories are the basis of nearly every recommendation that can be found for the use of fertilizers in growing crops. The facts applied to the grape, however, are that the average tillable soil contains a hundred or a thousand times more of the chemical const.i.tuents of plants than the grape can possibly take from the soil; and many experiments in supplying food to plants show that the chemical composition of the plant is not a safe guide to their fertilizer requirements. Later teachings in regard to the use of fertilizers are: That the quant.i.ty of mineral food in a soil may be of far less importance than the quant.i.ty of water, and that the cultivator should make certain that there is sufficient moisture in his land so that the mineral salts may be readily dissolved and so become available as plant-food; that far too much importance has been attached to putting chemicals in the soil and too little to the physical condition of the soil, whereby the work of bacteria and the solvent action of organic acids may make available plant-food that without these agencies is unavailable.

These brief and simple statements introduce to grape-growers some of the problems with which they must deal in fertilizing grapes, and show what a complex problem of chemistry, physics and biology fertilizing the soil is; how difficult experimental work in this field is; and how cautious workers must be in interpreting results of either experiment or experience. An account of an experiment in fertilizing a vineyard may make even more plain the difficulties in carrying on experiments in fertilizing fruits and the caution that must be observed in drawing conclusions.

AN EXPERIMENT IN FERTILIZING GRAPES

The New York Agricultural Experiment Station is experimenting with fertilizers for grapes at Fredonia, Chautauqua County, the chief grape region in eastern America. The experiment should be of interest to every grape-grower from several points of view. It not only shows that there are many and difficult problems in fertilizing grapes, but also the results of the use of manure, commercial fertilizers and cover-crops in a particular vineyard; it suggests the fertilizers to be used and the methods of use; and it furnishes a plan for an experiment by grape-growers who want to try such an experiment and draw their own conclusions. An account of the experiment and the results for the first five years follows:[10]

_Tests at Fredonia._

"In the vineyard at Fredonia eleven plats were laid out in a section of the vineyard where inequalities of soil and other conditions were slight or were neutralized. Each plat included three rows (about one-sixth of an acre) and was separated from the adjoining plats by a 'buffer' row not under test. One plat in the center of the section served as a check, and five different fertilizer combinations were used on duplicate plats at either side of the check. Plats 1 and 7 received lime and a complete fertilizer with quick-acting and slow-acting nitrogen; Plats 2 and 8 received the complete fertilizer but no lime; on Plats 3 and 9 potash was omitted from the complete fertilizer combination; Plats 4 and 10 received no phosphorus; Plats 5 and 11, no nitrogen; and Plat 6 was the check. The materials were applied at such rates that they provided for the first year 72 pounds of nitrogen per acre, 25 pounds of phosphorus and 59 pounds of pota.s.sium; and for each of the last four years two-thirds as much nitrogen and phosphorus and eight-ninths as much pota.s.sium. The lime was applied the first and fourth years in quant.i.ty to make a ton to the acre annually. Cover-crops were sown on all plats alike and were plowed under in late April or early May of each year. These differed in successive years, but included no legumes. The crops used were rye, wheat, barley and cow-horn turnips separately and the last two in combination.

"The cultivation differed only in thoroughness from that generally used in the Belt, the aim being to maintain a good dust mulch during the whole growing season. Pruning by the Chautauqua System was done throughout by one man, who pruned solely according to the vigor of the individual vines and left four, two or three, or no fruiting canes as appeared best. The vineyard was thoroughly sprayed, all plats alike.

"Low winter temperatures, affecting immature wood and buds caused by unfavorable weather of the previous season, reduced yields materially during two of the five years, and practically neutralized any antic.i.p.ated benefit from fertilizers. Following the first of these low-crop years, came a season, 1911, in which favorable conditions, acting upon vines left undiminished in vigor by the light crop of the previous year resulted in heavy and quite uniform yields on all the plats.

"The yields for the five years are shown in Table I; and a summary showing the average gains from each treatment is given in Table II, with the average financial balance after deducting the cost of fertilizer application from the increased returns from the plats receiving them.

TABLE I.--YIELD OF GRAPES (TONS PER ACRE) IN FERTILIZER EXPERIMENTS

========================================================================= Plat. 5-year No. 1909 1910 1911 1912 1913 avg.

-----+-------------------------+------+------+------+------+------+------ _Tons_ _Tons_ _Tons_ _Tons_ _Tons_ _Tons_ 1 Complete fertilizer; lime 4.48 2.10 5.37 3.46 2.14 3.51 2 Complete fertilizer 4.76 2.21 5.71 4.30 2.83 3.96 3 Nitrogen and phosphorus 5.17 2.14 5.61 4.00 2.25 3.83 4 Nitrogen and potash 4.25 2.55 5.64 4.10 2.85 3.87 5 Phosphorus and potash 3.41 2.00 5.44 4.35 1.78 3.39 6 Check 3.38 2.10 5.32 3.60 1.24 3.12 7 Complete fertilizer; lime 4.69 2.38 5.62 4.80 3.04 4.10 8 Complete fertilizer 4.66 2.07 5.71 4.98 2.72 4.02 9 Nitrogen and phosphorus 4.99 2.04 5.35 4.89 2.61 3.97 10 Nitrogen and potash 4.79 2.26 5.91 4.89 3.07 4.18 11 Phosphorus and potash 4.99 1.87 5.03 4.21 1.97 3.61 =========================================================================

TABLE II.--AVERAGE INCREASE IN GRAPE YIELDS AND AVERAGE FINANCIAL GAIN FROM FERTILIZER APPLICATIONS

N = nitrogen, P = phosphorus, K = pota.s.sium, Ca = lime.

Gains in tons per acre.

======================================================================== N, P, N, P, N, P. N, K. P, K.

K, Ca. K. ----------------------+---------+---------+---------+---------+--------- _Tons_ _Tons_ _Tons_ _Tons_ _Tons_ First plat of pair 3.51 3.96 3.83 3.87 3.39 Second plat of pair 4.10 4.02 3.97 4.18 3.61 ---------+---------+---------+---------+--------- Average 3.80 3.97 3.90 4.02 3.50 Check plat 3.12 3.12 3.12 3.12 3.12 ---------+---------+---------+---------+--------- Average gain .68 .85 .78 .90 .38 Average financial gain $5.82 $13.84 $14.05 $18.54 $6.99 ========================================================================

From this last table the benefit from nitrogen appears quite evident since every combination in which it appears gives a substantial gain over the one from which it is absent. Phosphorus and pota.s.sium without the nitrogen, lead to only a slight increase over the check; and lime appears to be of no benefit. Financially, the complete fertilizer and lime combination, the nitrogen and phosphorus combination and the phosphorus and pota.s.sium combination failed to pay their cost in five of the ten comparisons; the complete fertilizer was used at a loss four times out of ten; and the nitrogen and pota.s.sium combination three times out of ten. Lime had no appreciable effect on either vines or fruit.

"No effect of the fertilizers on the fruit itself, aside from yield, was shown for the first three years; but in 1912, and even more markedly in 1913, the fruit from the plats on which nitrogen had been used was superior in compactness of cl.u.s.ter, size of cl.u.s.ter and size of berry. In 1912 also, when early ripening was a decided advantage, the fruit on the nitrogen plats matured earlier than that on the check plats. In 1913 the favorable ripening season and the smaller crop tended to equalize the time of ripening on all plats. The grapes on the phosphorus-pota.s.sium plats were better in quality than those in the check plats but not as good as those on the plats where nitrogen was used.

"Other indexes also show plainly the benefit from nitrogen in this vineyard; for size and weight of leaf, weight of wood produced and number of fruiting canes left on the vines were all greater where fertilizers, and particularly nitrogen, had been used. The three-year averages (1911-1913) of the measurements for these characteristics are shown in Table III:

TABLE III.--COMPARATIVE PRODUCTION OF LEAVES, WOOD AND FRUITING CANES ON GRAPE VINES DIFFERENTLY FERTILIZED

(Averages for three years.)

======================================================================= FERTILIZER APPLICATION LEAF WOOD FRUITING WEIGHT[11] PRUNED[12] CANES LEFT[13]

----------------------------+------------+------------+---------------- _Grams._ _Lbs._ Complete fertilizer; lime 1,033 1,295 2,468 Complete fertilizer 1,010 1,367 2,609 Nitrogen and phosphorus 1,047 1,272 2,585 Nitrogen and pota.s.sium 1,069 1,401 2,646 Phosphorus and pota.s.sium 964 1,086 2,326 Check 930 915 2,110 =======================================================================

_Cooperative experiments._

"In order to secure information as to the behavior of fertilizers on the different soils of the Grape Belt, cooperative tests were carried on in six vineyards owned, respectively, by S. S. Grandin, Westfield; Hon. C. M. Hamilton, State Line; James Lee, Brocton; H. S. Miner, Dunkirk; Miss Frances Jennings, Silver Creek; and J. T. Barnes, Prospect Station. The soil in these vineyards included gravelly loam, shale loam and clay loam, all in the Dunkirk series, and the experiments covered from two to two and a half acres in three cases and about five acres in each of the other vineyards. The work continued four years in all but one of the experiments, which it was necessary to end after the second year.