Issue link: http://winesandvines.uberflip.com/i/907666
December 2017 WINES&VINES 55 PRACTICAL WINERY & VINEYARD GRAPEGROWING with the fact that available soil phosphorus levels were quite low. There was no evidence of micronutrient remobilization to support canopy needs within the young grapevines. Zinc accumu- lated to high levels in the fruiting cane and scion trunk, and copper accumulated in the smallest roots. Potassium accumulated in fruit clusters, and magnesium accumulated in petioles, similar to previous findings. 11 The quantities discussed for each nutrient required by young Pinot Noir grapevines as- sumes they are carrying a typical crop yield (about 2 tons per acre) in Oregon's Willa- mette Valley. Grapevine management and nutrient analysis methods The seasonal timing of biomass and nutrient distribution among different vine organs was determined over two growing seasons in four- year-old Pinot Noir grapevines grown in field micro-plots producing their first typical crop for the region. Field micro-plots (pot-in-pot vineyard) allow better control of the root en- vironment and provide easier access to all vine roots. The more uniform soil conditions in micro-plots and use of young vines allowed micronutrient uptake to be determined for the first time under field conditions. Vines were fertilized in the spring, and the biomass and nutrient contents of nine sepa- rate vine parts were measured at six pheno- logical stages (bud break, bloom, véraison, harvest, leaf fall and dormancy) each year. The grapevines (Dijon 115 clone [FPS 73] on 3309C rootstock) were grown for three years in 60-liter pot-in-pot micro-plots filled with a 1:1 (vol:vol) mixture of coarse sand and Jory series soil (a red-hill soil with low phosphorus). Each micro-plot at bud break of each year received a complete fertilizer (20- 10-20) with Mg (0.15%) and micronutrients (0.05% Zn, 0.05% Mn, 0.025% B, 0.0125% Cu and 0.005% molybdenum [Mo]) to the equivalent of 30 pounds per acre N, 6.6 pounds per acre P, and 25 pounds per acre K. Vines were drip-irrigated and water inputs managed based on measures of volumetric soil water content and vine water status. 12 Vines were cane-pruned and head-trained on a single Guyot system with vertical shoot positioning. A small crop (averaging 0.5 clus- ters per shoot) was retained in the third growing season. In year four (experimental year), two fruit clusters were retained on each fruiting shoot. Ten vines were destructively harvested at each growth stage in 2007 and 2008. The fresh mass for each vine part was recorded, subsamples were dried and finely ground, and nutrient concentrations were determined using appropriate methods. 10 Total vine biomass and total nutrient con- tent changes between the first three growth n Clusters n Leaves n Petioles n Shoots n Fruiting Canes n Scion Trunk n Rootstock Trunk n Woody Roots (>4 mm) n Small Roots (1-4 mm) Tissues in four-year-old grapevines from a micro-plot are sampled over two growing seasons. Data are means for each plant part, with standard errors of the mean shown for total vine nitrogen content (n=10). Letters designate major phenological stages. BB=bud break; BL=bloom; VR=véraison; HA=harvest; LF=leaf fall; PR=pruning at winter dormancy. CHANGES IN NITROGEN CONTENT 13 12 11 10 9 8 7 6 5 4 3 2 1 0 April '07 June '07 Aug. '07 Oct. '07 Dec. '07 Feb. '08 April '08 June '08 Aug. '08 Oct. '08 Dec. '08 Feb. '09 Vine Nitrogen (g) BB BL VR HA LF PR BB BL VR HA LF PR n Clusters n Leaves n Petioles n Shoots n Fruiting Canes n Scion Trunk n Rootstock Trunk n Woody Roots (>4 mm) n Small Roots (1-4 mm) Tissues in four-year-old grapevines in a micro-plot are sampled over two growing seasons. Data are means for each plant part, with standard errors of the mean shown for total vine potassium content (n=10). Letters designate major phenological stages. BB=bud break; BL=bloom; VR=véraison; HA=harvest; LF=leaf fall; PR=pruning at winter dormancy. CHANGES IN POTASSIUM CONTENT 13 12 11 10 9 8 7 6 5 4 3 2 1 0 April '07 June '07 Aug. '07 Oct. '07 Dec. '07 Feb. '08 April '08 June '08 Aug. '08 Oct. '08 Dec. '08 Feb. '09 Vine Potassium (g) BL VR HA BB LF PR BL VR HA LF PR BB