Mechanical Canopy and Crop Load Management of Pinot Gris. Joseph P. Geller and S. Kaan Kurtural

Transcription

1 Mechanical Canopy and Crop Load Management of Pinot Gris Joseph P. Geller and S. Kaan Kurtural

2 3.6 million tons of wine grapes grown in CA More than 50% comes from the San Joaquin Valley More than 60% of Pinot gris acreage is also grown in the San Joaquin Valley Much of the Pinot gris acreage is grown on two or three wire single curtain, non-positioned trellis Introduction

3 Constraints to consistent large volume Profit margins are low Yield is paramount in the SJV 12 tons/a (based on 7 x 11 spacing) Growers can only afford to prune Mechanical hedging: Retains too many nodes Out of balance vines Too much fruit for the amount of leaf area Too much leaf area for the amount of fruit production

4 An example Below threshold

5 Crop Load Management Single most important management practice Balancing potential crop size with canopy size and sunlight interception Crop load is not a direct measurement Ratio between vegetative and reproductive growth Crop yield per dormant pruning weight unit Optimum = 5 to 10 lb/lb Leaf area per fruit weight Optimum values = 1.1 to 1.4 m 2 per kg fruit

6 Recent work in the SJV Mechanical pruning combined with mechanical shoot thinning (7 shoots/ft) AND Differential RDI (50% ETo post fruitset to veraison) Crop load = 9.9 (lb/lb) BUT Yield achieved was below economic threshold for region

7 Justification Insufficient understanding in warm climate optimum canopy architecture and cropping levels Pinot gris vine balance in warm climate Production variability does not justify current costs Hypothesis Achieving vine balance of Pinot Grigio through mechanical canopy and crop load management is possible without adversely affecting components of yield and fruit composition in a warm climate

8 Goal Optimize mechanical crop load and canopy management methods Sustain production Sustain pruning weight Maintain vine balance in a warm climate Specific objectives: Determine interactive effects of mechanical canopy management Canopy architecture and microclimate Yield components and fruit composition Objectives

9 Plant material and experiment set-up Pinot gris/1103p In Arvin, CA 160 A planting Premier sandy-loam soil Drip-irrigated: 0.5 gal/h emitters 7 x 11 N-S oriented rows Trellis: California sprawl The experiment was: 2 x 3 x 2 factorial RCBD with 4 replications Two pruning methods Three shoot densities Two leaf removal Sampled on a grid every 76 th vine

10 Materials and Methods Two pruning methods Spur Mechanical hedging Three shoot densities Low (seven shoots/ft) Medium (ten shoot/ft) High (No thinning) Two leaf removal Yes No Canopy architecture Canopy microclimate Fruit composition Brix, ph, TA Yield components Yield efficiency Crop load Leaf area to fruit ratio Pruning weight / ft

11 Pruning treatments Spur pruning 22 spurs with two buds Manual application Mechanical hedging Sprawl-type pruner head (Oxbo Model w/power pack) Four-inch hedge was retained

12 Mechanical pruner

13 Shoot thinning treatments Applied mechanically Shoots 10 to 12 in length Rotary-paddle shoot thinner Oxbo rotary brush

14 Shoot thinning implement

15 Leaf removal treatments Applied mechanically 20 days postbloom On East side of canopy 18 window within the fruiting zone Oxbo Int. Model Leaf Remover

16 Leaf removal implement

17 RESULTS

18 Wine making and analysis Wine Making Each treatment harvest at 22 o Brix by hand Rep 1+2, Reps 3+4 Two reps/treatment Vinified in 7570 L lots, ph adjusted to 3.3 Analytical methods E&J Gallo Analytical Labs in Modesto, CA Six months post-bottling

19 Table 1 Interactive effects of pruning method and shoot density on average number of count, non-count, and total shoots per meter of canopy row on Pinot gris/1103p in 2010 and 2011 a Pruning method + shoot density HP + Low SD HP + Medium SD HP + High SD MP + Low SD MP + Medium SD MP + High SD Pr>F e Main Effects (Pr>F) Pruning method Shoot density Count shoots ± SE b Non-count shoots ± SE c Total shoots ± SE d Count shoots ± SE Non-count shoots ± SE Total shoots ± SE 6.4 ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ±

20 Table 2 Effects of pruning method, shoot density, and leaf removal on canopy architecture of Pinot gris/1103p in 2010 and 2011 a Distance between shoots (in) c Canopy area (m 2 ) Distance between shoots (in) Pruning method Canopy area (m 2 ) b Exposed shoots / A d Leafiness index e Exposed shoots / A Leafiness index Hand pruning b 1.97 a 27,940 b b 2.31 a 24,200 b Mechanical hedging a 0.96 b 58,652 a a 1.11 b 56,760 a Pr>F Shoot density Low ,456 b a 35,640 b a Medium ,900 ab a 30,800 b b High ,400 a b 55,000 a b Pr>F Leaf removal No ,172 b , Yes ,420 a , Pr>F Interactive effects P x SD f P x LR g SD x LR h Pr>F P x SD x LR i

21 Table 3 Effects of pruning method, shoot thinning, and leaf removal on canopy micro-climate post shoot thinning and leaf removal of Pinot gris/1103p in 2010 and a Pruning method % PAR transmittance b Leaf layers c % Canopy gaps d Cluster contacts e % PAR transmittance Leaf layers % Canopy gaps Cluster contacts Hand pruning b a Mechanical hedging a 8.19 b Pr>F Shoot density Low b b Medium b b High a a Pr>F Leaf removal No 6.05 b 4.56 a 8.33 b b 2.75 a 2.60 b 0.56 Yes 9.56 a 3.77 b 26.0 a a 1.89 b 5.80 a 0.60 Pr>F Interactive effects P x SD f P x LR g SD x LR h Pr>F P x SD x LR i

22 Table 4 Effects of pruning method shoot thinning and leaf removal on yield components of Pinot gris/1103p in 2010 and a Pruning method + shoot density Berry weight (g) ± SE Clusters/vine ± SE Cluster weight (g) ± SE Yield (tons A -1 ) ± SE Berry weight (g) ± SE Clusters/vine ± SE Cluster weight (g) ± SE Yield (tons A -1 ) ± SE HP + Low SD 1.23 ± ± ± ± ± ± ± ± 0.37 HP + Medium SD 1.18 ± ± ± ± ± ± ± ± 0.41 HP + High SD 1.30 ± ± ± ± ± ± ± ± 0.46 MP + Low SD 1.37 ± ± ± ± ± ± ± ± 0.49 MP + Medium SD 1.37 ± ± ± ± ± ± ± ± 0.50 MP + High SD 1.08 ± ± ± ± ± ± ± ± 0.76 Pr>F b Interactive effects P x LR c SD x LR d Pr>F P x SD x LR e Pr>F Main effects Pruning method Shoot density Leaf removal

23 Fruit composition (Pruning method)

24 Fruit composition (Shoot density)

25 Table 5 Effects of pruning method, shoot thinning, and leaf removal on pruning weight, Ravaz index and leaf area to fruit ratio of Pinot gris/1103p in 2010 and a Pruning method + shoot density Pruning weight (lb/ft) ± SE b Crop load ± SE c Leaf area: fruit (m 2 /kg) ± SE d Pruning weight (lb/ft) ± SE Crop load ± SE Leaf area: fruit (m 2 /kg) ± SE HP + Low SD 0.75 ± ± ± ± ± ± 0.13 HP + Medium SD 0.78 ± ± ± ± ± ± 0.11 HP + High SD 0.75 ± ± ± ± ± ± 0.13 MP + Low SD 0.64± ± ± ± ± ± 0.21 MP + Medium SD 0.56 ± ± ± ± ± ± 0.18 MP + High SD 0.49± ± ± ± ± ± 0.18 Pr>F e Interactive effects Pr>F P x LR f SD x LR g P x SD x LR h Pr>F Main effects Pruning method Shoot density Leaf removal

26 Crop Load Management

27 Crop load management

28 Labor operations costs and net returns Labor cost/ha Net income/ha

29 No leaf removal What happened to the wine/with the wine? Leaf removal

30 Discussion Pruning method or shoot thinning alone Not as effective as their combination (Terry and Kurtural 2011) Reduction of contribution of non-count shoots to total shoots aided by shoot removal in Pinot gris Leaf removal Effective in reducing: Canopy leaf layers Effective increasing Canopy gaps

31 Discussion Berry size affected by shoot density in each year Reduction in berry size did not reduce yield although cluster weight was reduced Yield was maintained with medium shoot density treatment in both years Hand pruned treatments 2X yield in some shoot densities possibly due to ameliorated Fruit composition at the farm gate Warm climate viticulture Differences at the farm gate statistically significant Horticultural significance? Pruning wt maintained between: 0.55 lb/ft 0.67 lb/ft (Kliewer and Dokoozlian 2005) However, crop load greater than previously reported window of 5 to 10

32 Conclusions Pinot gris grown in warm climate: Mechanically hedge to 4 bearing surface Mechanically shoot thin to 11 shoots/ft No leaf removal Banana, pineapple, green apple peel flavor retained in the wine Results in: Crop load of Leaf area to fruit ratio of 0.8 to 1.2 m 2 /kg Maintains vine size up to 0.67 lb/ft Vine balance for consistent large volume production for economic sustainability

33 THAT S GREAT! SO, WHAT? What is next?

34 A Systems Approach

35 Vineyard efficiency through spatiotemporal crop load management (Bates et al) CA (Wine) Uniform Deficit irrigation + Machine Experimental early stress Sprawl Deficit irrigation Approach Yes Small Low Medium No Small High High Yes Large Low Low No Large High Medium Canopy characterization Crop characterization Crop load Management Automation

36 Acknowledgements Greg T. Berg American Vineyard Foundation Cal. Agri. Res. Init. Nat. Grape and Wine Init.

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