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BACKGROUND AND AIMS: Spatial and temporal variability of vine vigour within a vineyard block, associated with variation in soil physical and chemical properties, affects yield, and fruit and wine composition. The objectives of this study were to measure this variability and possible causes for a commercially important vineyard area in Hawke's Bay, New Zealand. METHODS AND RESULTS: Three vigour classes, and measurement of vine nutrient and water status, vegetative growth and canopy attributes, yield, fruit ripening profiles, and grape and wine composition over two seasons characterised vigour variability of Cabernet Sauvignon vines growing on the ‘Gimblett Gravels’ area of Hawke's Bay, New Zealand. Vine nutrition and growth differed between vigour zones with extreme nitrogen deficiencies recorded. Vigour did not affect vine phenology. Normalised Difference Vegetative Index measurements quantified vigour differences. High vigour vines showed a higher yield, but fruit ripeness, wine anthocyanins and phenolics, and some sensory attributes were significantly reduced. Excessively leafy canopies associated with high vigour were responsible for these effects. CONCLUSIONS: Soil‐induced vine nutrient deficiencies, rather than differences in vine water status, influenced vine vigour. Measures of vegetative growth and canopy attributes suggested negative implications of excessive shading with high vine vigour. SIGNIFICANCE OF THE STUDY: This study showed the relative significance of nutrition in affecting vine vigour on sandy gravel soils. A good correlation between remotely sensed vigour zones, and grape and wine composition permit on‐ground zonal management to minimise the negative effects of spatial variability.

Grapevine growth and production is limited in the Port Macquarie region by acidic subsoils and high exchangeable aluminium. Root growth is restricted to about 15 cm depth, and despite high growing season rainfall (920 mm, September to March) which exceeds predicted evapotranspiration for the period (400 mm), the vines suffer periodic water stress. Slotting is a technique of subsoil amelioration allowing thorough incorporation of lime to depth. Slots are 150 mm wide, and in this experiment were installed to 400 mm depth. The aim of slotting is to improve root growth in the subsoil, thus increasing plant access to water and nutrients previously inaccessible. The experiment was conducted in a Chardonnay vineyard planted in 1982. Lime was incorporated into the slots at about 2 t ha⁻¹ with a further 8 t ha⁻¹ spread on the surface, mixed and moved to form an undervine bank. Soil and root samples were taken in February, 1990. Slotting caused pHCaCl2 to increase from 4.3 to 5.0 to 400 mm depth. Associated with this was a more than ten-fold increase in root length density. The slotting technique gives the opportunity to improve dense, poorly drained acidic soils and make them suitable for horticulture production.

Relative water content may be accurately estimated using the ratio of tissue fresh weight to tissue turgid weight, termed here relative tissue weight. That relative water content and relative tissue weight are linearly related is demonstrated algebraically. The mean value of r2 for grapevine (Vitis vinifera L. cv. Shiraz) leaf tissue over eight separate sampling occasions was 0.993. Similarly high values were obtained for maize (Zea mays cv. Cornell M-3) (0.998) and apple (Malus sylvestris cv. Northern Spy) (0.997) using a range of leaf ages. The proposal by Downey and Miller (1971. Rapid measurements of relative turgidity in maize (Zea mays L.). New Phytol. 70: 555-560) that relative water content in maize may be estimated from water uptake was also investigated for grapevine leaves; this was found to be a less reliable estimate than that obtained with relative tissue weight. With either method, there is a need for calibration, although this could be achieved for relative tissue weight at least with only a few subsamples.

LONDON. AFTER a lifetime spent in musical criticism,\" says Ernest Newman, \"I find that I can no longer read it--thus, I imagine, coming at last into line with the general public.\" His reason is that it tells him nothing about the composer, who is the real object of his interest, but only...