|REEVE, ALISON - Oregon State University
|SKINKIS, PATRICIA - Oregon State University
|VANCE, AMANDA - Oregon State University
|TARARA, JULIE - Ste Michelle Estates
Submitted to: HortScience
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/25/2016
Publication Date: 11/14/2016
Citation: Reeve, A.L., Skinkis, P.A., Vance, A.J., Lee, J., Tarara, J.M. 2016. Vineyard floor management influences 'Pinot noir' vine growth and productivity more than cluster thinning. HortScience. 51:1233-1244. https://doi.org/10.21273/HORTSC10998-16.
Interpretive Summary: Vine vigor control and crop load management are important practices in the production of premium wine grapes. To better understand the relationship between canopy size and yield within the framework of a cool-climate premium production wine grape vineyard, the effects of crop thinning ‘Pinot noir’ vines of varying vigor were investigated in Oregon’s Willamette Valley during 2011 to 2013. To manipulate vigor, the vineyard floor was managed with a competitive plant; depending on treatment, red fescue was grown on both alleyways of a row of vines (Grass), or alternating sides (Alternate), or neither side of the flanking alleyways (Tilled). The competition plant altered vine vegetative growth, yield, and fruit N concentrations while cluster thinning primarily affected berry composition. Using perennial grass cover in high vigor vineyards may be an effective management strategy to reduce canopy size while maintaining sufficient canopy to ripen fruit. The reduced canopy size and fruit N concentration found with growing a long-term perennial grass cover implies yields may be reduced over time, though not by decreased water availability, but by the limitation of N uptake due to competition. While no supplemental irrigation was required at this site, commercial producers may need to consider soil depth and type when evaluating the benefits of using perennial grasses as part of their vineyard management. Producers who choose to use a perennial grass cover crop will need to monitor vine N status, fruit YAN at harvest, and supplementation of N should be considered in the winery or vineyard when levels become low enough to result in reduced fruit quality or yield.
Technical Abstract: Vigor and crop level management are important practices for premium wine grape production. The implications of crop thinning ‘Pinot noir’ (Vitis vinifera L.) vines of varying vigor were investigated in the Willamette Valley of Oregon in 2011 to 2013, to better understand the relationship between canopy size and yield within the framework of a cool-climate, premium production wine grape vineyard. To manipulate vigor, a competitive grass cover crop (Festuca rubra L.) was grown in both (Grass), alternating (Alternate), or neither side of the flanking alleyways (Tilled). Vines within each vineyard floor treatment had two crop levels applied, including cluster thinning to one cluster per shoot (Half Crop) or no crop thinning (Full Crop). Grass treatment had reduced leaf area and leaf N concentrations during all years compared to Tilled treatments. Photosynthesis was also lower in Grass treatments despite more light in the canopy interior. Grass treatments had less yield than Tilled treatments in two of three years and lower yeast assimilable nitrogen (YAN) concentrations in fruit every year. There was limited impact of floor treatments on total soluble solids (TSS) and pH. Reduced yields through cluster thinning had limited impact on vegetative growth but increased TSS and pH, in two of three years. There were few floor management by crop level interactions in any year. Grass effectively reduced vegetative growth to moderate vigor levels with cane weights between 20 and 40 g. Utilizing a competitive grass cover crop may be an effective strategy to reduce excessive vine growth and require less labor in canopy management and crop thinning without compromising basic fruit ripeness, although YAN levels need to be monitored.