ISHS Acta Horticulturae 512: XXV International Horticultural Congress, Part 2: Mineral Nutrition and Grape and Wine Quality
VINEYARD NITROGEN SUPPLY AND SHIRAZ GRAPE AND WINE QUALITY |
| Authors: | M.T. Treeby, B.P. Holzapfel, G.J. Pickering, C.J. Friedrich |
| Keywords: | Vitis, grape quality, nitrogen, rootstocks, sensory evaluation, wine quality |
| Abstract:
Nitrogen is frequently the most limiting plant nutrient for grape production in the warm irrigated regions of inland Australia. Consequently, must N levels are often insufficient to sustain a fermentation through to dryness without supplementation with exogenous N. A novel N supply strategy was trialled on drip-irrigated Shiraz vines growing on three different rootstocks to improve grapejuice N levels and supply vine N needs, aiming to satisfy winemakers' requirements for grapes that can ferment to dryness, and grape producers' need for profitable productivity. Targeting the Summer N uptake period resulted in significant improvements in grape juice assimilable amino N levels. Grapes from vines receiving N during Summer had more colour than grapes from vines that received N during Autumn or unfertilised control vines. However, potentially higher final wine colour was not realised. Organoleptic assessment of the wines indicated that both N supply and rootstock affected final wine quality. Vineyard N supply affected aroma as well as colour, overall impression of the wine and total score. Wines made from grapes from vines receiving heavy applications of N were perceived to be of lower quality than wines made from grapes from vines that received no N or moderate amounts of N, irrespective of application time. Rootstock also significantly affected wine colour and aroma. Highly significant rootstock and N supply interactions were apparent for colour intensity, | |
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