High Tunnel Grape Production Systems: A Novel Sustainable Approach to Growing Grapes

Final report for LS17-282

Project Type: Research and Education
Funds awarded in 2017: $266,986.00
Projected End Date: 03/31/2021
Grant Recipient: University of Arkansas
Region: Southern
State: Arkansas
Principal Investigator:
Renee Threlfall
University of Arkansas
Co-Investigators:
Dr. M. Elena Garcia
University of Arkansas Division of Agriculture
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Project Information

Abstract:

Grape production is a high profit global enterprise with the United States (US) as one of the top ten countries in yield, area harvested, and tons produced. Although the majority of US grape production occurs in California, grape production in the southern region can be a profitable enterprise. However, grapes grown in the southern region are an extremely high input crop because of pest pressures (diseases and arthropods) in a humid climate requiring frequent fungicide and insecticide inputs (6-8 fungicides and 4-6 pesticide applications per season). Organic grape production is not an economically viable option in the southeastern United States due to the prevalence of disease and insect pests (e.g. black rot and grape berry moth). The economic and environmental sustainability of table grape production in the southern United States could be improved by producing grapes in protected agriculture systems such as high tunnels (HT).  Preliminary results of table grape cultivation at the University of Arkansas (Fayetteville) under HT systems has demonstrated that production can be advanced (production can be achieved one year after planting instead of the two to three years in field production), fruit quality can be improved, and fungicide and insecticide inputs can be reduced (from 10-14 spray applications in open field vineyards to 2-4 in HTs). Establishment costs and payback periods for HT production of table grapes are needed to assess economic feasibility for southern region growers, but could be applied to other grape production regions. A multidisciplinary approach by the UA System Division of Agriculture will evaluate HT grape production as a sustainable way to diversify farm operations. Division researchers in horticulture, food science, pest management, and economic fields will collaborate with the Arkansas Association of Grape Growers and local growers in underserved regions. Production requirements, pest management, postharvest qualities, and economic and marketing considerations will be identified, assessed, and incorporated into educational programs. A partnership with the National Center for Appropriate Technology (NCAT) will aid in developing and disseminating project deliverables and publications. The information generated over the course of this project will guide future growers and entrepreneurs through the decision­ making processes involved in implementing this novel approach to HT table grape production.

Project Objectives:

Objective 1. Evaluate high tunnel table grape cultural and pest management methods by investigating potential management techniques.

Objective 2. Determine marketable attributes through the evaluation of physiochemical and post-harvest attributes for table grapes grown under high tunnels.

Objective 3. Develop economic budgets for high tunnel table grape production by determining economic breakeven analysis.

Objective 4. Generate production practices for high tunnel grape growers by creating pest management and best practice guides from project research results.

Objective 5.  Expand outreach efforts for high tunnel grape production.

 

Cooperators

Click linked name(s) to expand

Research

Materials and methods:

Objective 1. Evaluation of high tunnel table grape cultural and pest management methods by investigating potential grape production management techniques (Garcia, Lee, AAGG)

Grape cultivar and trellis system performance in HTs will be evaluated. An established HT (UA, Fayetteville¬ 2014) with three table grape cultivars and three training systems will be used to assess table grape production. A new HTs will be established at a grower collaborator site (GCS). Data will be collected on vine growth and yield parameters. Soil conditions (pH, mineral nutrients, etc.) will be monitored by collecting soil samples. Foliar samples will be collected to determine nutrient status of vines and supply fertilizers as needed.  Insect traps will be placed in the HT vineyards and monitored weekly for grape berry moth and other insects affecting grapes, including spotted wing drosophila. Evaluations will be done weekly for improved control of fruit rot diseases. Frequency of pesticide application will be monitored as well as assessing effectiveness of sustainable approaches such as the exclusion insect netting and release of predatory species for arthropod control. Fungicide applications will be evaluated for optimal spray timing, efficacy, and phytotoxicity. For comparison we will collect data from grapes established plantings at FSR and GCS.

Objective 2. Determine marketable attributes for high tunnel grapes (Threlfall)

We will identify and measure physiochemical attributes of the HT grapes at harvest and during postharvest storage for each cultivar and trellis system at each site. Physiochemical attributes will include physical, composition, and nutraceutical attributes. The physical attributes of the grapes will include cluster weight, berries/cluster, berry weight, berry dimensions, external berry color and texture. The composition of the grapes will include soluble solids, pH, titratable acidity, organic acids and sugars.  The nutraceutical attributes of the grapes will include total phenolics, total ellagitannins, total flavanols and total anthocyanins. The postharvest attributes (texture, weight loss and percent unmarketable fruit) of the table grapes will be evaluated at harvest and each week for three weeks stored at 2°C. Wine will be made from the wine grapes in years 2 and 3 and analyzed for some composition attributes (pH, titratable acidity, alcohol, acids and sugars).

Objective 3. Develop economic budgets for HT grape production (Thomsen)

Characterize economic potential for HT grape production by developing economic breakeven analysis and impacts.  Economic analysis will rely on enterprise budget (Smith et al, 2000) and partial budgeting techniques to estimate costs and returns for production, harvesting, and marketing activities of table and wine grapes.  The economics of recommended production practices will be evaluated by collecting data from research recommendations and field trials.  Specific information related to HT operations—cost/rate of application of inputs, tunnel cost, harvest processes, etc.—will be analyzed to estimate production costs/acre.  Budgets will assist farmers in management decisions including identifying break-even prices and determining allocation of resources to land, labor, and capital.

Objective 4. Generate production practices for high tunnel grape growers by creating pest management and best practice recommendations from project results (Garcia, Lee, Rainey, Threlfall, AAGG)

From the data generated on cultural and pest management practices applied to the HT table grapes during Year 1 and 2, we will develop integrated pest management and best practice fact sheets and videos to guide stakeholders in their decision making process (Extension educators, growers, agricultural consultants, etc.). 

Objective 5. Expand outreach efforts for high tunnel grape production (AAGG, Garcia, Lee, Thomsen, Threlfall)

Disseminate HT grape production information through fact sheets, videos, ATTRA-NCAT webpage, field days, workshops, and state and regional conferences to stakeholders. The project team will host an annual workshop on findings of research and issues related to HT grape production.  Fact sheets and videos  will be posted on the SSARE website for use throughout the southern region and made accessible to interested individuals by various means such as e-book, cd, flash drives and hard copies.

Research results and discussion:

Objective 1. To evaluate cultural and pest management methods for high tunnel table grape by investigating potential grape production management techniques. 

Year  1:

  • Grape planting established at Barnhill Orchards. Activities:
  • Barnhill Orchards
  • Helped grower on land preparation
  • Helped grower with trellis establishment
  • Ordered and planted 81 grape vines (27 of each cultivar: Gratitude, Hope, and Jupiter)
  • Set landscape fabric
  • Trained vines throughout the season
  • Helped with put the plastic on bay

Chateau Aux Arc Vineyards and Winery

  • Site selection and land preparation for new tunnel
  • Ordered vine plants (18 of each cultivar: Jupiter, Hope, and Neptune
  • Ordered a 25’x200’ Super Solo Tunnel to be set-up 18 spring

Fayetteville:

  • Pruning and training was conducted in established planting
  • Other standard horticulture practices such as fertilizer application, cluster thinning, combing, and harvesting were conducted
  • Pest management practices were applied including spraying and scouting
  • An internship was granted to an undergraduate student to help with the above activities (Southern ASHS 

Fayetteville yield results:

Yield results were very high despite the utilization of “balanced pruning” techniques (Table1_17 Results).  These high yields resulted in poor fruit quality, delayed harvest, and more disease incidence. Pruning adjustments will be made for the 2018 season.

Objective 2. Determine marketable attributes for high tunnel grapes.

Fruit was collected from the Fayetteville tunnel and phytochemical analyses were conducted.  These results were presented by a graduate student at the Southern Am. Soc. Hort Sci in Jacksonville FL.: High Tunnel Table Grapes, Post Harvest. Molly Felts_

Objective 3. Develop economic budgets for HT grape production.

     Data was collected to generate budgets

Objective 4. Generate production practices for high tunnel grape growers by creating pest management and best practice guides from project results

     Data was collected to generate guides.

Objective 5. Expand outreach efforts for high tunnel grape production.

     Production of videos and fact sheets was initiated 

Final Summary Results: 

Objective 1:

For this objective, studies were conducted at two locations in Arkansas (Fayetteville and Cabot) to evaluate table grape cultivar performance (vine and yield characteristics) grown in high tunnels (HT) under different trellis system (modified double high cordons – MDHC and Geneva Double Curtain- GDC) and to evaluate the effect of cluster thinning practices (no cluster thinning, clusters thinned when grapes were pea size, or clusters thinned when grape were at veraison) for crop load management on these cultivars. The MDHC trellis systems were designed to increase the space efficiency within the HT, meaning that one side of the MDHC was trellis was higher to fit the slope of the tunnel sides. There were open-field plots of these cultivars at both sites, but the vines did not survive or struggled to survive, so were not presented in this study. In terms of other cultural practices performed, open-field vineyard standards were used on the table grape vines under the HT (leaf, shoots, combing, etc.).

In 2014, three table grape cultivars: Faith, Gratitude, and Jupiter, were planted in Fayetteville in an 8 x 61m Haygrove Super Solo HT on three trellis systems, MDHC- east and west sides of tunnel and GDC in the center of the tunnel. In 2017, three table grape cultivars, Hope, Gratitude, and Jupiter, were planted in Cabot, AR in an 8 x 76 m Haygrove Multi-bay HT on three trellis systems, MDHC systems on the east and west side of the tunnel and GDC was in the middle of the tunnel). In 2017, only the cultivar performance of the trellis systems was evaluated. Trellis systems and cluster thinning were evaluated in 2018 and 2019 where during both years of the study, ‘Jupiter’ was the most productive and best-performing cultivar under the HT at both locations.  In 2018 the yield for ‘Jupiter’ was 49 lbs. per vine and number of clusters was 90 clusters per vine. In 2019, yield per vine increased to 83 lbs. and the number of clusters rose to 197 clusters per vine.  However, high levels of inputs were required to balance vines (clusters per leaf growth) due to excessive vegetative and reproductive growth. Further research will need to be conducted for recommendations to growers about other best-performing table grape cultivars under the HT.

Evaluation of trellis systems demonstrated that the MDHC east had higher yields (41 lbs. in 2018 and 82 lbs. in 2019) compared to GDC and MDHC west and GDC. Although, the MDHC trellis systems were designed to increase the space efficiency within the HT, as vines matured, the lower (most exterior) canopy had high levels of shading that influenced the timing of harvest. The higher (more interior) canopy ripened faster with more sunlight exposure than the lower shaded canopy.

Cluster thinning was applied to manage crop load, but based on the results of this study, cluster thinning did not reduce yields during either year of this study. In Fayetteville, mature vines of two cultivars (Faith and Jupiter) over-cropped in 2019, meaning that the crop load of the vines was not balanced and still had excessive yields. Cluster thinning at the Fayetteville location did not influence most of the cultivar performance variables measured.

At Cabot, Gratitude vines had winter damage in 2017 and most of the vines died the following spring 2018. Thus, this cultivar was not included in the results. Since vines were established in the Spring of 2017 at Cabot, the vines were not fully mature. The remaining cultivars at this location (Hope and Jupiter) did not over crop during either year of the study, but cluster thinning did not have effect on yield per vine. There was no reduction in yield and if the study were to continue for another year or two, over-cropping might become a problem as it was at the Fayetteville site. For future studies, mature vines would need to be evaluated to compare cluster thinning (none and thinned) or other crops management like shoot thinning or leaf thinning. One recommendation to better adjust crop load would be to perform more intense cluster thinning under the HT. Instead of treating cluster thinning on a per shoot basis, the amount of thinning would need to be based on the whole vine vigor. Although leaving a lower cluster number than in our would result in reduced yields, there could be an increase in fruit quality. However, this would also mean that labor inputs would increase to ensure the proper and accurate crop load on the vines. Cluster thinning activity is a time-consuming process that requires large amounts of labor to complete and might not be economically viable in large operations.

Vines under the HT were extremely vigorous with large amounts of long shoots and oversized leaves. This made it difficult to navigate through the HT and resulted in reduced air flow. Although relative humidity was not much higher in the HT microclimate compared to open-field conditions, it was higher and could have become greater if leaf and shoot thinning practices had not been applied. The large amounts of vegetative growth made it difficult to properly cluster thin and made it difficult to apply pesticides. Pesticide applications were done using a powerful professional-grape backpack air-blast sprayer, but it was cumbersome to carry and control within the HT and to achieve appropriate spray coverage due to vigorous vine growth. Increased plant spacing and increased row spacing would be a recommendation for further research and for growers looking to establish their own vines under HTs. This would result in each vine having more space and reduce the amount of space competition from each vine. In terms of cultural practices performed little vine control was gained from these practices and further research will need to be conducted to recommend cultural practices that are appropriate for table grape vines grown under HT conditions.

These studies determined that table grape production under HT technologies in Arkansas was productive and feasible in areas where open-field production is costly with little economic viability, but more research is required to give an overall recommendation to growers wanting to establish vines under HTs in similar growing areas. Overall, HT table grape production is still a new concept that requires more research and currently is more suited towards small acreage growers, with a focus on fresh-market table grapes, due to highly vigorous and productive vines that result in increased labor inputs. Results were presented at the 2020 Southern ASHS by graduate student J. Hernandez (Canopy management  and Cluster thinning). 

Objective 2: 

Four Arkansas table grape cultivars were tested to address this objective: Faith, Gratitude, Hope, and Jupiter at locations cited above. These culitvars were also sampled from a conventional field location for comparison purposes only (no statistical analysis conducted for the comparison). Different treatments of cluster thinning were applied to assess any effects of this practice postharvest on marketability attributes. The table grapes were assessed extensively on the day of harvest as well as during three storage times across a three-week time frame. On the day of harvest, the cultivars Jupiter and Gratitude appear to consistently have positive marketability traits regarding flavor, texture, color, and berry size. High tunnel-grown grapes exhibited lower levels of decay and berry drop in comparison to the field site. Cluster thinning did not have much notable impact upon table grape quality at harvest for the high tunnel-grown grapes. During storage, ‘Gratitude’ and ‘Hope’ appeared to perform well in many marketability traits including firmness, low berry drop, low decay, and rich berry coloration. The cultivar Faith had high rates of decay and tended to diminish in positive marketability aspects during storage more than the other cultivars. Overall, the cultivar Gratitude had the highest quality at all stages of this experiment, while the cultivar Faith had the lowest marketability quality. For storage purposes, cluster thinning treatments did not have notable effects on berry quality. Thus, cluster thinning practices may not be necessary for enhancing fruit quality of high-tunnel-grown table grapes. Further, the high tunnel-grown grapes appear to have similar or improved measurements of marketability during storage in comparison to the field site. Based on these observations of the table grapes at harvest and during postharvest storage analyses, high tunnel technology may be a viable option for growing high-quality table grapes in southeastern United States. Results were presented at the 2020 Southern ASHS by graduate student V. Beasley (Postharvest and Jupiter Marketability).

 

Objective 3: 

Data was collected on all activities related to table grape HT operations—cost/rate of application of inputs, tunnel cost, harvest processes, labor, etc.  for two consecutive years and was analyzed to estimate to estimate production costs/acre. The Fayetteville site was used to generate an enterprise budget  (Table 1. Production budget) on two cultivar Jupiter (red grape) and Gratitude (white grape) both on Geneva Double Curtain training system. This training system is commonly used by the industry.  A fact sheet was produced to guide and help growers when deciding to adopt HT technologies when growing table grapes (High Tunnel Grapes: Economic Analysis). 

For a detailed, complete budget analysis refer to Excel file (ArkansasTableGrapeHighTunnelBudget).

Objective 4:

Data was collected for all pest management activated throughout the duration of the project.  Pest management practices consisted of insecticide applications based on scouting and a preventative fungicide program. During the project’s duration, pheromone traps were used to monitor the presence of grape berry moth and were checked biweekly. In 2018, there were nine fungicide and three insecticide and miticide applications made.  In 2019, there were eight fungicide applications and four insecticide and miticide applications made.  For both years, a Sulforix® application was made during the dormant period in March. In mid-April biweekly fungicide applications began once shoots emerged and continued after harvest. Insecticides were applied when there were grape berry moth catches made in the pheromone traps or if Japanese beetles were present.  The main pest problems encountered in the tunnel were sour rot and bird damage. Bird netting was placed around the tunnel to prevent birds from entering the tunnel.  A fact sheet on pest management was published that highlights HT table grape pests and measures applied to manage the problems.  This fact sheet includes an example of a spray schedule (High Tunnel Grapes: IPM).

Objective 5

Data collected from research objectives generated the following professional and industry presentations, three thesis, seven videos and five fact sheets

Presentation-Role of SSARE Sponsored Fruit Research and Education Programs in Arkansas to Benefit Grape, Strawberry, and Blackberry Producers at the Annual Hispanic Farmers Conference in McAllen, TX. Dec 10, 2017

Presentation- Small Fruit Production in High Tunnels: Challenges and Successes.  Alabama Fruit and Vegetable Growers- Clanton, AL, Nov 17, 2017.

Presented and delivery a workshop and field day activities on high tunnel systems at Lonoke and Cabot-April 14, 2018.

Planned, conducted, and delivered presentation at a workshop on protected agriculture in Eureka Springs- March 2, 2018

Presentation on High Tunnel Fruit Production at AR-OK Horticulture Industries Show in Fayetteville, AR on Jan. 5, 2018. Included yield and fruit quality results from 2017 high tunnel grape project. P.I,  graduate and undergraduate students presented their research results. 

Presentation at the Assoc. of Grape Growers (AAGG) Annual Meeting . Nov 2. -Potential for High Tunnel Table Grape Production in Arkansas. AAGG, Fayetteville, AR

Presentation -Evaluation of cluster thinning for Arkansas table grapes grown under high HIS-Jan 11 &12, 2019, Fayetteville AR.

Presentation-A Three Year Summary of Table Grapes Grown Under High HIS, Fayetteville Ar. Jan 11 &12, 2019

Organized workshop on Fruit Production in High Tunnels at the Southern Sustainable Agriculture Workers- Jan 18, 2019, Little Rock, AR.

Presentation- Table Grape Production Utilizing High Tunnels: A Sustainable Approach to Growing Grapes. 9th International Table Grape Symposium.  Santiago, Chile.  Feb 16-21, 2020.

Presentation- Effect of Cluster Thinning on Postharvest Attributes of Table Grapes Grown in High Tunnel. 9th International Table Grape Symposium. Santiago, Chile.  Feb 16-21, 2020.

Presentation- Results of a Two-Year Study on the Performance of Table Grape Cultivar Jupiter with Cluster Thinning Treatments Under High Tunnels at Two Locations in Arkansas. 2020 Annual Meeting of the SASHS.  Louisville, K.Y.  Jan 31-Feb 2, 2020

Presentation- Two Year Study of Marketability Attributes of Jupiter Table Grape Grown Under High Tunnels at Two Locations in Arkansas. 2020 Annual Meeting of the SASHS.  Louisville, K.Y.  Jan 31-Feb 2, 2020.

Presentation- Canopy Management Evaluation of Three Arkansas Table Grape Cultivars: Gratitude, Faith, and Jupiter Grown Under a High Tunnel System. 2020 Annual Meeting of the SASHS. Louisville, K.Y.  Jan 31-Feb 2, 2020.

M.S. student, Virginia Beasley, Department of Horticulture, Co advised Dr. Elena Garcia and Dr. Renee Threlfall.  Thesis Title: Evaluation of Cluster Thinning for Arkansas Table Grapes Grown in High Tunnel Systems, 2018-2020

M.S. student, Jose Hernandez, Department of Horticulture. Advisor Dr. M. Elena Garcia. Thesis Title: Effects of Pruning and Cluster Thinning on Table Grapes Grown Under High Tunnel Systems, 2018-2020

M.S candidate, Molly Felts, Department of Food Science. Dr. Renee Threlfall, Thesis Title: Postharvest Physiochemical Analysis and Nutraceutical Evaluation of Arkansas Grown Peaches, Table Grapes, and Muscadine Grapes,  2016-2018

Beasley, V.*, R.T. Threlfall, J. Hernandez., K. Pruitt, and M.E. Garcia. 2020. Postharvest storage performance of three table grape cultivars: Gratitude, Faith, and Jupiter under a high tunnel system. HortScience 55(9) (Supplement 2) – 2020 SR-ASHS Annual Meeting. P. S402

Beasley*,V.C., R.T. Threlfall, and M.E Garcia. 2019. Impact of Cluster Thinning on Postharvest Attributes of Table Grapes Grown in a High Tunnel System. HortScience 54(9) (Supplement 2) – 2019 SR-ASHS Annual Meeting. P. S369

Beasley*,V.C., R.T. Threlfall, and M.E Garcia. 2019. Postharvest Attributes of Arkansas Table Grapes Grown in a High Tunnel System. HortScience 54(9) (Supplement 2) – 2019 SR-ASHS Annual Meeting. P. S393

Felts*, Molly, R.T. Threlfall, J.R. Clark, and M.E. Garcia. 2018. Effects of High Tunnel Production on Postharvest Marketability of Arkansas Table Grapes. HortScience 53(9) (Supplement) – 2018 SR-ASHS Annual Meeting. P. S495.

Videos

Fact Sheets 

 

Participation Summary
2 Farmers participating in research

Education

Educational approach:

Information on HT grape production practices was disseminated and delivered via fact sheets (ATTRA/NCAT and SSARE webpages),videos (posted on YouTube (ATTRA/NCAT and SARE websites), workshops, and state and regional conferences to stakeholders. The project team hosted annual workshop on findings of research and issues related to HT grape production. We provided support to create and implement web­ based materials for extension ­based outreach at the ATTRA/NCAT webpage. All these materials can be available via flash drives upon request (megarcia@uark.edu)

Educational & Outreach Activities

20 Consultations
12 Curricula, factsheets or educational tools
2 Journal articles
4 On-farm demonstrations
2 Tours
14 Webinars / talks / presentations
5 Workshop field days

Participation Summary

120 Farmers
15 Ag professionals participated
Education/outreach description:

Presentation-Role of SSARE Sponsored Fruit Research and Education Programs in Arkansas to Benefit Grape, Strawberry, and Blackberry Producers at the Annual Hispanic Farmers Conference in McAllen, TX. Dec 10, 2017

Presentation- Small Fruit Production in High Tunnels: Challenges and Successes.  Alabama Fruit and Vegetable Growers- Clanton, AL, Nov 17, 2017.

Presented and delivery a workshop and field day activities on high tunnel systems at Lonoke and Cabot-April 14, 2018.

Planned, conducted, and delivered presentation at a workshop on protected agriculture in Eureka Springs- March 2, 2018

Presentation on High Tunnel Fruit Production at AR-OK Horticulture Industries Show in Fayetteville, AR on Jan. 5, 2018. Included yield and fruit quality results from 2017 high tunnel grape project. P.I,  graduate and undergraduate students presented their research results. 

Presentation at the Assoc. of Grape Growers (AAGG) Annual Meeting . Nov 2. -Potential for High Tunnel Table Grape Production in Arkansas. AAGG, Fayetteville, AR

Presentation -Evaluation of cluster thinning for Arkansas table grapes grown under high HIS-Jan 11 &12, 2019, Fayetteville AR.

Presentation-A Three Year Summary of Table Grapes Grown Under High HIS, Fayetteville Ar. Jan 11 &12, 2019

Organized workshop on Fruit Production in High Tunnels at the Southern Sustainable Agriculture Workers- Jan 18, 2019, Little Rock, AR.

Presentation- Table Grape Production Utilizing High Tunnels: A Sustainable Approach to Growing Grapes. 9th International Table Grape Symposium.  Santiago, Chile.  Feb 16-21, 2020.

Presentation- Effect of Cluster Thinning on Postharvest Attributes of Table Grapes Grown in High Tunnel. 9th International Table Grape Symposium. Santiago, Chile.  Feb 16-21, 2020.

Presentation- Results of a Two-Year Study on the Performance of Table Grape Cultivar Jupiter with Cluster Thinning Treatments Under High Tunnels at Two Locations in Arkansas. 2020 Annual Meeting of the SASHS.  Louisville, K.Y.  Jan 31-Feb 2, 2020

Presentation- Two Year Study of Marketability Attributes of Jupiter Table Grape Grown Under High Tunnels at Two Locations in Arkansas. 2020 Annual Meeting of the SASHS.  Louisville, K.Y.  Jan 31-Feb 2, 2020.

Presentation- Canopy Management Evaluation of Three Arkansas Table Grape Cultivars: Gratitude, Faith, and Jupiter Grown Under a High Tunnel System. 2020 Annual Meeting of the SASHS. Louisville, K.Y.  Jan 31-Feb 2, 2020.

M.S. student, Virginia Beasley, Department of Horticulture, Co advised Dr. Elena Garcia and Dr. Renee Threlfall.  Thesis Title: Evaluation of Cluster Thinning for Arkansas Table Grapes Grown in High Tunnel Systems, 2018-2020

M.S. student, Jose Hernandez, Department of Horticulture. Advisor Dr. M. Elena Garcia. Thesis Title: Effects of Pruning and Cluster Thinning on Table Grapes Grown Under High Tunnel Systems, 2018-2020

M.S candidate, Molly Felts, Department of Food Science. Dr. Renee Threlfall, Thesis Title: Postharvest Physiochemical Analysis and Nutraceutical Evaluation of Arkansas Grown Peaches, Table Grapes, and Muscadine Grapes,  2016-2018

Beasley, V.*, R.T. Threlfall, J. Hernandez., K. Pruitt, and M.E. Garcia. 2020. Postharvest storage performance of three table grape cultivars: Gratitude, Faith, and Jupiter under a high tunnel system. HortScience 55(9) (Supplement 2) – 2020 SR-ASHS Annual Meeting. P. S402

Beasley*,V.C., R.T. Threlfall, and M.E Garcia. 2019. Impact of Cluster Thinning on Postharvest Attributes of Table Grapes Grown in a High Tunnel System. HortScience 54(9) (Supplement 2) – 2019 SR-ASHS Annual Meeting. P. S369

Beasley*,V.C., R.T. Threlfall, and M.E Garcia. 2019. Postharvest Attributes of Arkansas Table Grapes Grown in a High Tunnel System. HortScience 54(9) (Supplement 2) – 2019 SR-ASHS Annual Meeting. P. S393

Felts*, Molly, R.T. Threlfall, J.R. Clark, and M.E. Garcia. 2018. Effects of High Tunnel Production on Postharvest Marketability of Arkansas Table Grapes. HortScience 53(9) (Supplement) – 2018 SR-ASHS Annual Meeting. P. S495.

 

 

Videos

Fact Sheets 

Learning Outcomes

80 Farmers reported changes in knowledge, attitudes, skills and/or awareness as a result of their participation

Project Outcomes

5 Farmers changed or adopted a practice
1 Grant received that built upon this project
Project outcomes:

Grapevines are one of the most important horticultural crops world-wide. In the southern U.S. region, Arkansas included, hot and humid climate accompanied by high pest pressure requires high levels of labor and pesticide inputs, making open field table grape production unsustainable. This project demonstrated that HT’s systems, by providing moderate environmental control (protection from low winter temperatures and rain), can allow for a reduction of pesticide inputs compared to field conditions.  And as a result, we saw precocity (fruit production the year after planting instead of production in the second year), increased yields, and better fruit quality. However, we saw increased labor inputs due to excessive vigor and increased productivity of vines.  This project determined that table grape production under HT technologies can improve the environmental and economic sustainability of table grape production in areas where open-field production is costly with little economic viability. 

 Comments from attendees to a High Tunnel Workshop 5/3/18 

    • 62 attendees
    • 95% of participants said the workshop was “extremely useful”
    • Speakers on average were rated as 4/5 or 5/5 for “usefulness” of the material they presented by 74.4 % of participants.
    • 44% of participants said the field tour was “5/5-very useful”
    • Some of the comments we received included:
      • “I was amazed by the high tunnel grape project. I had little interest in it before the workshop, but left very interested.”
      • “Getting the opportunity to really see a high tunnel operation.”
      • “Thanks for putting in the effort to help your customers. The Extension service has for a long time been a great source for information for small growers, and you are doing a great job.”
      • “Great conference. Really liked the farm visit.”
      • “Everyone involved did a fantastic job and preparation was evident”
Recommendations:

This project represents the first integrated high tunnel table grape research conducted in the US and it generated more questions that could have been answer in scope and timeline of the project.  This project determined that table grape production under HT technologies was productive and economically feasible in areas where open-field production is costly with little economic viability, but we saw increased labor inputs due to excessive vigor and increased productivity of vines. Some of the cultural management practices we applied such as cluster thinning and vine combing did not seem to affect the vigor (vegetative and  fruiting) of the vine.  This excessive vigor resulted in poorer fruit quality (color and disease incidence) and difficulties when applying  pesticides.  

One recommendation to better adjust crop load would be to perform more intense cluster thinning under the HT. Instead of treating cluster thinning on a per shoot basis, the amount of thinning would need to be based on the whole vine vigor. Perhaps, leaving a lower cluster number than what our study did would result in reduced yields. However, this would also mean that labor inputs would increase to ensure the proper and accurate crop load be left on the vines.  Cluster thinning activity is a time-consuming process that requires large amounts of labor to complete and might not be economically viable in large operations.

Another recommendation would be to increase plant spacing for growers looking to establish their own vines under HTs. This would result in each vine having more space and reduce the amount of space competition from each vine. In terms of cultural practices performed, open-field vineyard standards were used on the table grape vines under the HT (leaf, shoots, and cluster thinning, combing, etc.). These practices did not apply well to the vines under the HT. Little vine control was gained from these practices and further research will need to be conducted in order to recommend cultural practices that are appropriate for vines grown under HT conditions.

 

 

Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.