Location: Horticultural Crops Research
Title: Influence of vine vigor and crop level on ‘Pinot noir’ vine growth, nutrition, fruitfulness, and fruit composition Authors
Submitted to: American Journal of Enology and Viticulture
Publication Type: Abstract Only
Publication Acceptance Date: April 3, 2014
Publication Date: N/A
Technical Abstract: Oregon ‘Pinot noir’ vineyards are characterized as having high vegetative vigor and low yields, resulting in low crop loads, which is exacerbated by cluster thinning. A study was conducted from 2011 to 2013 to evaluate the impacts of vegetative vigor and crop level on growth and fruit composition of ‘Pinot noir’. Vine vigor was modified using a combination of perennial grass and tillage in the alleys. Two crop levels (no thinning and one cluster per shoot) were imposed within each floor management treatment. Floor management treatments effectively altered vegetative vigor as the presence of the grass (Grass) flanking the vine row reduced shoot growth, vine leaf area at bloom and véraison, lateral shoot growth, and dormant pruning weights during 2011 to 2013 compared to vines with alternating grass and tillage or complete tillage. The decline in vine size (23 to 46% reduction in leaf area at véraison) was attributed to a reduction in nitrogen concentration in leaf blade and petioles measured at bloom and véraison. Volumetric soil moisture did not differ among floor management in 2012 and 2013. Decreased soil moisture was seen in Grass during summer 2011, but this did not decrease midday stem water potential. Yeast assimilable nitrogen concentration of fruit was 53 to 66% lower in Grass compared to other treatments, reflecting the reduced vine nitrogen status. Despite increased solar radiation in the canopy, Grass had decreased fruitfulness (12 to 22%) in 2012 and 2013 and yield (18 to 43%) in 2011 and 2013. Cluster thinning created a range of leaf area to yield ratios which were positively related to total soluble solids and berry anthocyanin concentration and negatively related to tannin concentration. Results of this work suggest that altered nitrogen status of vines proportionally reduced vine growth and yield, attaining similar vine balance.