w i n e G R O WIN G
Increasing N at bloom
N1
50
N5
N10
40
100%
20
10
50
40
30
20%
20
10
50
Delphinidin 3 glc
Cyanidin 3 glc
Petunidin 3 glc
Peonidin 3 glc
Malvidin 3 glc
40
30
20
2%
Decreasing light at véraison
Anthocyanins (mg/g skin fw)
30
10
0
0
2
4
6
8 0
2
4
6
8 0
2
4
6
8
Weeks after véraison
Figure IV: Nitrogen supply during bloom can influence the susceptibility of grapevines to
unfavorable environmental conditions later in the season. Note how more nitrogen at bloom results
in a less-balanced anthocyanin profile in the grape skins, especially when combined with low-light
stress at véraison. For explanations see Figure III (modified from Keller and Hrazdina 1998).
Color is among the quality attributes
most easily influenced by nitrogen availability, but it is also linked to water supply. Both timing and amount of nitrogen
supply depend on vine nitrogen status,
climate, weather and soil properties. The
goal is to achieve balanced vines with an
open canopy and ideal microclimate for
high yields and top quality grapes.
The relationship between grape yield
and quality is complex and can be influenced by a variety of cultural practices.
Nitrogen supply is one of these practices
that, along with water supply, is crucial
for vine growth, yield formation and
fruit quality. Errors made in nitrogen
management cannot be corrected by
other cultural practices, such as canopy
management. PWV
Edited from Proceedings of the 13th
International Enology Symposium at the
Institut National de la Recherche Agro
nomique (INRA) de Montpellier, France,
sponsored by International Association of
Enology, Management, and Wine Marketing,
oenology.de.
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