February 20, Portland, OR. Gill Giese Ciro Velasco-Cruz

Transcription

1 Root pruning, Intra-row Ground Cover and Cabernet Sauvignon February 20, Portland, OR Gill Giese Ciro Velasco-Cruz

2 Today s talk Context Premise and study conditions Root pruning and ground covers Results and Discussion What? Ground cover agronomy Vine reaction Berry composition Why? Vine root reaction Water Nitrogen Impacts

3 Context: experimental vineyard Yadkin Valley AVA, Surry County, NC elev. ~ 1080 Winston-Salem Greensboro Durham Raleigh Asheville Charlotte North Carolina Vineyards Vineyard or Winery ~ 186 wineries ~ 525 vineyards ~ 2,300 acres of bunch (non-muscadine) grapes Miles

4 Precipitation (inches/month) Temperature ( F o ) Context: North Carolina and Oregon Salem, OR Medford, OR Dobson, NC Monthly maximum temperatures (degrees F o ) Fairview complex clay loam, ( m rooting depth), well drained, kaolinitic, mesic, Typic Kanhapludults Jan Feb Mar Apr May June July Aug Sept Oct Nov Dec Salem, OR Medford, OR Dobson, NC Monthly precipitation (inches) ~12 ft Jan Feb Mar Apr May June July Aug Sept Oct Nov Dec Growing Degree Days o F Salem, OR = 2385 (2005 to 2017) Medford, OR = 3237 (2001 to 2013) Dobson, NC = 3634 (2005 to 2011)

5 Excessive vigor?

6 Experimental background Problem: excessive vine vigor Hypothesis: intra-row ground cover and root pruning would limit water and nitrogen, reduce vine vigor Objectives: Assess agronomic performance of ground covers Describe and quantify treatment effects on vine growth, shoots, roots, berry and wine parameters Long term treatment effect on vineyard?

7 Experimental design: RCBD, six replications B B B B G G G G B B B B buffer row B B B B G G G G B B B B buffer row B B B B G G G G B B B B buffer row B B B B G G G G B B B B buffer row B B B B G G G G B B B B buffer row B B B B G G G G B B B B buffer row TRT 1 KY-31 fescue TRT 2 Aurora Gold fescue TRT 3 Perennial ryegrass Block (REP) One TRT 4 Orchardgrass TRT 5 Elite II fescue TRT 6 Herbicide

8 KY-31 Fescue Aurora Gold Fescue Elite II Fescue Perennial Ryegrass Orchardgrass

9 Root pruning

10 Ground cover biomass Mg DM ha -1 Cover crop Dec Oct June Oct Oct Mean KY-31 fescue 3.10 a 2.21 a 1.23 ab 3.40 ab 2.44 a 2.22 a Aurora Gold fescue 2.90a 2.65a 1.22ab 3.56ab 2.03ab 1.97 ab Perennial ryegrass 0.69c 0.76b 0.86b 1.97b 0.93c 0.95 d Orchardgrass 2.23ab 1.09b 1.33a 2.49ab 1.17bc 1.59 c Elite II fescue 1.72 b 1.44 b 0.86 b 3.75 a 2.08 ab 1.75 bc Main effects and interactions Ground cover < Year_month < Ground cover x Year_month <0.0001

11 Ground cover stand density, 2008, 2010 (higher number = greater density, fewer weeds)

12 Shoot growth rate (cm/day) Shoot growth rate (cm/day) Shoot growth rate (cm/day), Non root pruned 5 Root pruned a a a a b b Shoot growth rate (cm/day) May to June NRP Herbicide = 3.22 Grass = May KY-31 fescue Perennial ryegrass Orchardgrass Elite II fescue Herbicide strip May 29 May- 9 Jun 9-20 Jun Jun May May 29 May- 9 Jun 9-20 Jun Jun RP Herbicide = 2.96 Grass = May May May 9 Jun Jun Jun Ground cover ns ns Root pruning ns < < Ground cover x root pruning ns ns ns ns ns

13 Pruning wt. (kg/meter of canopy) Pruning weights (kg/m), 2005 to drought year no summer hedging new cordons Herbicide non-root pruned Herbicide root pruned KY-31 fescue non-root pruned KY-31 fescue root pruned Elite II fescue non-root pruned Elite II fescue root pruned

14 Percentage pruning weight (kg/m) change, 2005 to 2009 Grass plots Herbicide plots % reduction due to: RP NRP RP NRP Grass RP Grass + RP Mean % change 05 to 09 % change 05 to 09 39% 26% 17% 6%

15 * vines grown with herbicide strip = 2.77 crop load Percent change in crop load (Ravaz index), 2005 to 2009 Spring 2016

16 Vine yield (kg/vine), 2005 to 2011 Cover crop Root Pruning Mean 2017 KY-31 fescue RP b 2.95 NRP a 2.42 Mean Aurora Gold fescue RP NRP Mean Perennial ryegrass RP b NRP a Mean Orchardgrass RP b NRP a Mean Elite II fescue RP NRP Mean Herbicide strip RP NRP Mean

17 Root extraction 2008, 2010

18 Root intercept quantification 2008, 2010 broom like growth root reaction root pruned non-root pruned

19 Root distribution as a function of soil depth, Y = (1- ß d ) May 2008 Cumulative fraction of total root biomass at cm soil depth (%) Ground cover 0-20 cm cm cm cm cm ß d KY-31 fescue c Herbicide strip b October 2010 Cumulative fraction of total root biomass at cm soil depth (%) Ground cover 0-20 cm cm cm cm cm ß d KY-31 fescue a Herbicide strip a

20 Soil core extraction, 2014

21 Depth (cm) Depth (cm) Comparison of methods to determine root biomass distribution soil monolith extraction , 2010 soil core extraction R² = R² = Root biomass (g) Root biomass (g)

22 Depth (cm) Depth (cm) Root length density, KY-31 fescue Elite II Herbicide strip KY-31 fescue Elite II Herbicide strip Fine--Root length density (mm/cm 3 ) Coarse Root Length density (mm/cm 3 )

23 Soil volumetric water content (%)

24 Total petiole bloom (% of dry wt) Petioles collected at bloom recommended N% = 1.2 to 2.1% Fescue KY-31 Aurora Fescue Perennial Ryegrass Orchardgrass Elite II Fescue Herbicide Control Mean RP 0.83* * 0.80* * NRP 0.95* * 0.91* * Mean * Root pruning (Pr>F) RP NRP Mean 0.96ab 0.86c 0.91bc 0.90bc 0.86c 1.04a * Cover crop (Pr>F) RP 1.10 * * * * NRP 1.29 * * * * Mean * Root pruning (Pr>F) Ground Cover KY-31 fescue Elite II fescue Herbicide strip

25 Analysis of covariance: leaf petiole N% to pruning weights (kg/m), 2007, 2009 and 2010 Regression of leaf petiole N% to pruning weights 2007, 2009, 2010, 2014 and 2017

26 Slope, intercept comparisons of leaf petiole N % and pruning weights (kg/m) Cover crop Root pruning KY-31 fescue NRP KY-31 fescue RP p values for intercept comparisons Elite II fescue NRP Elite II fescue RP Herbicide strip NRP Herbicide strip RP KY-31 fescue NRP KY-31 fescue RP Elite II fescue NRP Elite II fescue RP Herbicide strip NRP Herbicide strip RP --- p values for slope comparisons KY-31 fescue NRP KY-31 fescue RP Elite II fescue NRP Elite II fescue RP Herbicide strip NRP Herbicide strip RP KY-31 fescue NRP KY-31 fescue RP Elite II fescue NRP Elite II fescue RP Herbicide strip NRP Herbicide strip RP ---

27 Berry nitrogen at harvest (YAN, ppm) KY-31 fescue Elite II fescue Herbicide Strip RP NRP Mean 163 b 121 b RP NRP Mean RP NRP Mean 210 a 263 a * Desired range of YAN at harvest ~ 140 to 180 ppm

28 Annual estimated herbicide costs (2017 prices) Herbicide strip 2005 to 2017* 1 acre 100 acre vineyard** Glyphosate Chateau (2x) , TOTAL / ACRE , Glyphosate Alion (1x) , TOTAL / ACRE , pre harvest Gramoxone? Ground cover Pruning time (minutes/vine) KY-31 fescue Elite II fescue Herbicide Strip 2017 RP 2.58 NRP 3.36 Mean 2.97 RP 2.98 NRP 3.04 Mean 3.02 RP 2.87 NRP 3.08 Mean 2.98 * Exclusive of labor, references for herbicide pricing: Vinesmith.com, Winegrape Herbicide Guide 2017/2018 and University of Florida IFAS extension, accessed: 2/2/2018, **100 acre assumes 50% treated

29 Impacts Intra-row ground cover: reduced pruning weights, vine vigor and size and can maintain vine size when RP no longer applied Treatment effect linked to vine N status, monitor N closely Minimal yield penalty with intra-row ground cover With different crop load? With unhedged vines? Elite II fescue superior to other tested grasses Root pruning works, but cost considerations? Other benefits: Herbicide use reduction Reduction of cultural costs? Erosion mitigation?

30 References Giese, G., C. Velasco-Cruz, L. Roberts, J. Heitman, and T.K. Wolf Complete vineyard floor cover crops beneficially limit grapevine vegetative growth. Sci. Hortic. 170: Giese, G., T.K. Wolf, C. Velasco-Cruz, L. Roberts and J. Heitman Cover crop and root pruning impacts on vegetative growth, crop yield components, and grape composition of Cabernet Sauvignon. Am. J. Enol. Vitic. 66: Giese, G., T.K. Wolf, C. Velasco-Cruz, and L. Roberts Cover crop and root pruning effects on the rooting pattern of SO4 rootstock grafted to Cabernet Sauvignon. Am. J. Enol. Vitic 67: Holland, S., A. Howard, J.L. Heitman, T.J. Sauer, W. Giese, T.B. Sutton, N. Agam, A. Ben-Gal, and J.L. Havlin Implications of an interrow fescue cover crop for below-canopy water dynamics in a vineyard. Agron. J. 106: Centinari M. et al. 2013, Cover crop water use in relation to vineyard floor management practices. Am. J. Enol. Vitic. 64: Smart, D. R., E. Schwass, A. Lasko, and L. Morano. 2006b. Grapevine rooting patterns: a comprehensive analysis and a review. Am. J. Enol. Vitic. 57:89-104

31 Acknowledgements Dr. Tony Wolf, Virginia Tech Dr. Molly Kelly, Penn State University Dr. Ciro Velasco-Cruz Dr. Josh Heitman and Mr. Adam Howard, North Carolina State University Dr. Lucas Roberts, Amazon Inc. Mary Simmons, Miguel, Julio, Vidal, Ernesto, and Luis Shelton Vineyards Funding or support: New Mexico State University Virginia Tech Shelton Vineyards, Dobson NC North Carolina Wine and Grape Council Virginia Wine Board

32 Thank you for your attention! Questions? Gill Giese Viticulture Extension Specialist