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 potassium; and for each of the last four years two-thirds as much nitrogen and phosphorus and eight-ninths as much potassium. The lime was applied the first and fourth years in quantity 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 anticipated 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. No. | 1909 | 1910 | 1911 | 1912 | 1913 | 5-year average | |
|---|---|---|---|---|---|---|---|
| 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 |