Nitrogen Management to Improve Vine N Status and Reduce
Atypical Aging of Wine in New York
Dr. Lailiang Cheng, Department of Horticulture, Cornell University, Ithaca, NY 14853 (email:
LC89@Cornell.edu; Phone: 607-255-1779; Fax: 607-255-0599)
Dr. Tim Martinson, Finger Lakes Grape Program, Cornell Cooperative Extension, Penn Yan, NY
14527
Dr. Thomas Henick-Kling, Department of Food Science, NYSAES, Geneva, NY 14456
Dr. Alan Lakso, Department of Horticultural Sciences, NYSAES, Geneva, NY 14456
Introduction
Atypical aging (ATA) of wine can potentially cause serious economic loss to the wine
industry in New York. Very little is known about the exact cause(s) of ATA on the viticulture
side. The general understanding is that ATA is induced by stresses on the grapevine. The critical
time appears to be before and during veraison. ATA occurs more frequently on dry vineyard sites
and in dry years. Nitrogen deficiency may play an important role in ATA as the identification of
ATA in Europe coincided with dramatic reduction of nitrogen use in vineyards. Although use of
nitrogen fertilizers varies widely among vineyards in New York, a significant proportion of the
vineyards uses little nitrogen fertilizers. The soil nitrate content in these vineyards can be very
low (5 ppm) around veraison (Martinson, 2002). In addition, most of the NY winegrape vineyards
do not have irrigation and rely totally upon rainfall. In drought years, the situation gets worse
because root uptake of nitrogen from soil may be further reduced by water stress. It is not known
if nitrogen deficiency alone would trigger ATA. Anecdotal reports from growers in the west
indicate that foliar N application at veraison helped control ATA, but no experiment has been
done to provide proof. If N deficiency alone induces ATA, foliar application of nitrogen around
veraison may help reduce ATA even under drought conditions.
In 2001, we set up a field trial to determine if nitrogen deficiency, alone or in
combination with water stress, causes ATA, and under what conditions (water stress or adequate
water supply) nitrogen application via foliage or soil at veraison improve vine nitrogen status,
fruit quality and consequently reduce occurrence of ATA under NY cool climate conditions.
Procedures
Mature Riesling vines on Couderc 3309 rootstock at a Seneca Lake vineyard were used in
the study. Two factors were considered: nitrogen fertilization and water supply before and during
veraison. There were two levels of water supply (no irrigation or irrigation) and three levels of N
fertilization (No N, foliar N, or soil N), resulting in a total of 6 treatment combinations: (1) No
irrigation nor N application; (2) No irrigation with foliar N application; (3) No irrigation with soil
N application; (4) Irrigation without N application; (5) Irrigation with foliar N application; and
(6) Irrigation with soil N application. All the treatments were replicated 5 times with two panels
of vines (6 vines) in each plot in a completely randomized design. There was one buffer panel
between any two adjacent plots and a buffer row between any two adjacent rows.
Drip irrigation was provided from July 18 through September 13 at 15,000 gal/acre/week.
For soil N treatment, urea was applied to soil surface at a rate of 30 lb actual N per acre on July
31. Foliar N sprays began on July 31 at a concentration of 0.8% urea solution (6.5 lb of urea/100
gal water at 200 gallons/acre) at weekly intervals for a total of 5 applications (equivalent to 30 lb
actual N).
Both vine N status and water status were monitored from veraison to harvest. Fruit from
all vines in the experimental units was hand harvested on October 16. Juice samples were taken
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for analysis. Harvested fruit was bulked into two lots and brought to the laboratory for
vinification. Reps 1, 2, and 3 of each treatment were bulked together for one lot; reps 4 and 5
were bulked together for the second lot. Twelve lots (6 treatments x 2 reps) of wine were made.
Results and discussions
1. Vine N status and water status
Leaf N content in the foliar N treatments tended to be higher than no nitrogen or soil N
treatments over the sampling period with significant difference (P<0.05) detected on leaf samples
collected on August 29. Soil N application or irrigation did not significantly affect vine N status.
N treatments did not alter vine water status. Non-irrigated vines had significantly lower
stem water potential than the irrigated vines in August and September. The non-irrigated vines
reached the threshold stem water potential for loss of photosynthesis in mid or late August, and
likely had impaired canopy function for about one month. Heavy rainfall in late September
appeared to have relieved the stress for the last 2 weeks before harvest.
2. Fruit yield and its components
Because vine size was quite variable, N application or irrigation did not significantly
affect total fruit yield per vine. However, some of the yield components did respond to irrigation
(Table 1). Berry weight and cluster weight were increased by irrigation from 1.59g to 1.74g and
from 88.1g to 97.7g, respectively. Berry number per cluster and cluster number per vine were not
significantly affected by irrigation. N applications did not significantly affect any of the yield
components.
3. Juice and wine
Juice samples were analyzed for soluble solids, yeast available nitrogen, pH, titratable
acidity, organic acids, and total phenolics. Foliar N application significantly increased yeast
available nitrogen, including both ammonium N and amino N (Table 2). In contrast, soil N
application at the same rate was not effective at all whether or not irrigation was provided.
Irrigation also increased yeast available nitrogen. The effects of foliar N application and
irrigation on yeast available nitrogen were additive as there was no interaction between N
application and irrigation. Irrigation significantly increased juice soluble solids whereas N
applications did not. Other juice quality parameters were not significantly affected by the
treatments (data not shown).
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Table 1. Effects of nitrogen applications and irrigation on Riesling yield
Treatments
Irrigation Nitrogen
No
0
Yield
(lb/vine)
10.6
Berry Wt
(g)
1.58
Berry#
(#/cluster)
55.7
Cluster Wt
(g)
87.7
Cluster #
(#/vine)
54.5
Foliar N
10.6
1.57
58.6
91.5
52.8
Soil N
9.6
1.62
52.9
84.4
50.1
0
10.0
1.73
58.8
99.8
45.1
Foliar N
8.3
1.74
54.9
95.2
38.7
Soil N
11.5
1.75
56.5
98.2
53.1
Irrigation
ns
P<0.01
ns
P<0.001
ns
N
ns
ns
ns
ns
ns
Yes
Significance
P values indicate the significance level. ns: non-significant.
Table 2. Effects of nitrogen applications and irrigation on Riesling juice soluble solids and yeast
available nitrogen
Treatments
Brix
Ammonium N
Amino N
Yeast available
Irrigation Nitrogen
(%)
(mg/L)
(mg/L)
N (mg/L)
No
0
20.3
81.5
99.5
180.9
Yes
Foliar N
20.0
111.5
165.6
277.1
Soil N
20.2
78.8
90.1
168.9
0
22.8
95.6
149.1
244.7
Foliar N
22.1
119.1
210.1
329.2
Soil N
22.7
90.3
154.5
244.8
P<0.0001
P<0.01
P<0.001
P<0.001
ns
P=0.067
P<0.001
P<0.001
Significance
Irrigation
N
P values indicate the significance level. ns: non-significant.
Preliminary analysis of finished wines did not show significant difference in pH,
titratable acidity, or organic acids between treatments. Terpene aroma compounds and ATA
indicator substances (Indole, skatole, 2-aminoacetophenone, ethylanthranilate, and
methylanthranilate) are being analyzed. Wines will be also evaluated for sensory characteristics
by trained taste panelists.
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Summary
Foliar N application before and during veraison improved vine N status and increased
the level of juice yeast available nitrogen (including ammonium and amino N). During the dry
growing season of 2001, irrigation increased berry size and soluble solids by improving vine
water status. Irrigation also increased juice yeast available nitrogen. The level of yeast available
nitrogen was highest when both foliar N application and irrigation were provided. It appears that
foliar N application was very effective in increasing juice yeast available nitrogen even under
water stress, whereas soil N application did not have any effect. Therefore, foliar N application
may provide NY growers a very useful management tool to increase yeast available nitrogen even
in a dry year. Effects of N application and irrigation on the occurrence of atypical aging of wine
remain to be evaluated, but we expect the experimental wines to have different characteristics
because of the significant differences in juice quality between treatments. The wines from this
experiment represent the first opportunity we have had to evaluate the effect of controlled
nitrogen and irrigation treatments on occurrence and development of ATA. Because of the
volume of wine produced, it was also possible to explore the effectiveness of ascorbic acid
treatment on ATA occurrence and development. Further research is warranted to evaluate
responses of both vine and wine to these treatments over multiple seasons.
Acknowledgment
We thank Dr. Kuo-Tan Li, Tom & Libby Prejean, and Jim Zimar for their participation and
cooperation in this project. This project was supported by Viticulture Consortium-Eastern Grant
Program. Thanks to Dr. Terry Acree and his group, Ed Lavin and Kathryn Deibler for the aroma
analyses and to Luann Preston-Wilsey and Chris Gerling for wine preparation and juice and
wine analysis.
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