Innovative undertrellis management for vineyards

Final Report for LNE12-322

Project Type: Research and Education
Funds awarded in 2012: $146,243.00
Projected End Date: 12/31/2015
Region: Northeast
State: New York
Project Leader:
Alice Wise
Cornell Cooperative Extension of Suffolk County
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Project Information

Summary:

Long Island grape growers seek affordable, environmentally responsible alternatives to the use of herbicides under the trellis. Herbicides and nitrates are the most common agricultural contaminants of Long Island aquifers (7, 8). Studies have shown that bare ground may enhance leaching of nitrates and pesticides (4, 5). Over three seasons, under vine mowing and seeded under vine cover crops were evaluated in two research trials. Performance of under vine mowing was tracked in four commercial vineyards. Cover crop demonstrations with clover and fescue were implemented in ten grower blocks. Fourteen growers were interviewed at the conclusion of the study to determine practices, costs and outcomes.

Production costs are of paramount importance to growers as winegrape vineyards are expensive to maintain. The typical herbicide regime averaged $95/acre for labor and materials. Site preparation and seeding for cover crops ranged from $94 to $188/acre plus seed. Seeding clover was as low as $30/a at a rate of 5 lbs/acre. However, clover required re-seeding after 2-3 seasons. Fescue was seeded at a high rate, as much as 220 lbs/acre, driving costs to ≥ $500/acre. However, fescue did not require re-seeding and appears likely to persist for > 4 years. Control of escape weeds was necessary for both cover crops and was done by hand at $40-80 annually. Under vine mowing, at approximately $120/acre, compared well to the herbicide regime. However, the price of suitable mowers, from $3,500 for a single head to over $15,000 for two mowing heads with a row middle mower, was a deterrent for some growers.

In interviews with growers, 100% of respondents mentioned elimination of herbicides, groundwater protection and control of excess vine vigor as the primary motivations for exploring alternative strategies. Measurement of leachate for nitrates was inconsistent due to successive summer droughts. On some dates, mowed plots had only 25% of nitrate-nitrogen compared to herbicide treated plots. Similarly, ppm nitrate-N was as much as 80% higher in clover plots compared to herbicide and fescue plots. Under vine mowing and fescue reduced vine pruning weight in 2013 but results were inconsistent in other years. Canopy management costs were not reduced as expected, nor were differences seen in cluster characteristics or fruit quality. This project took place during consecutive years of severe summer drought. Impacts on vine vigor and cluster characteristics may be more likely in seasons with average to above average rainfall as competition provided by green covers would help to tame excess vine vigor.

Management information and results were communicated to growers via field meetings, newsletters, a blog, website posts, two webcasts and ten Powerpoint presentations. A dedicated webpage is under construction.

Introduction:

For the millions of residents on Long Island, drinking water is provided by sole source aquifers. Because of sandy, shallow soils, groundwater contamination has been a major concern since the 1970’s. The most common sources of contamination include industry, septic systems, pharmaceuticals and personal care products, and agriculture (7, 8). Herbicides and nitrates are the most common agricultural contaminants (7, 8). Herbicides are commonly used in vineyards to maintain a weed-free zone under the trellis to minimize competition for water and nutrients. Nitrogen fertilizers are applied to boost vine growth and yield. Grape growers are eager to adopt management strategies that minimize pesticide and fertilizer inputs but there is scant information available on how to do this while maintaining optimal fruit quality. Due to various obstacles such as perceived high cost and negative impacts on vines, growers are reluctant to implement alternative vineyard floor management solutions without an in-depth understanding of strategies and costs.

Maintaining green cover under the trellis offers many potential environmental benefits compared to herbicide strips and practices such as repeated cultivation. Covers reduce erosion, improve soil organic matter, and promote beneficial insect species (6, 9). Green covers have been shown to enhance soil microbiology and nitrogen fixation, important for nutrient retention and release (1, 2). In studies by Merwin in NY and others worldwide, green cover under the trees consistently reduced pesticide and nitrate leaching in orchards (3, 4, 5).  Under vine cover crops and mowing are therefore strategies that directly address the most pressing issue in Long Island agriculture.

In addition to environmental benefits, research in under-vine management has demonstrated viticultural benefits. Many studies in temperate climates have shown the link between vegetation under vines and a reduction in vine vigor (1, 9, 10, 11).  There is evidence of reductions in various yield components, notably berry weight (9, 11). Lower yields and smaller berries in particular are often linked to improvements in wine quality, particularly in red varieties (11).

The goal of this study was to assess impacts of under vine green growth on vines and fruit; determine necessary practices; and document basic costs. We hypothesized that under vine covers would 1) reduce vine vigor and alter cluster characteristics, leading to more favorable ripening; and 2) reduce leaching of nitrate-nitrogen. Along with favorable impacts on vines, elucidation of practices and costs would motivate reluctant growers to explore these strategies.

References

  1. Hatch, T., Hickey, C., Wolf, T. 2011. Cover crop, rootstock, and root restriction regulate vegetative growth of Cabernet Sauvignon in a humid environment. Am.J.Enol.Vitic. 62:3, 298-311.
  2. Ingles, C., Scow, K. Whisson, D., Drenovsky, R. 2005. Effects of cover crops on grapes, yield, juice composition, soil microbial ecology, and gopher activity. Am.J.Enol.Vitic. 56: 1, 19-29.
  3. Landry, D., Dousset, S., Fourneir, J., Andreux, F. 2005. Leaching of glyphosate and AMPA under two soil management practices in Burgundy Vineyards (Vosne-Romanee, 21-France). Environ. Pollut. 138 (2): 191-200.
  4. Merwin, Ian. Vineyard floor management, soil health and environmental aspects. Talk given at the Long Island Agricultural Forum, Jan. 14, 2010, Riverhead, NY.
  5. Merwin, I., Ray, J., Steenhuis, T., Boll, J. 1996. Groundcover management systems influence fungicide and nitrate-N concentrations in leachate and runoff from a New York apple orchard. J.Amer.Soc.Hort.Sci. 121 (2): 249-257.
  6. Oregon LIVE – www.liveinc.org – Oregon Low Input Viticulture and Enology.
  7. Suffolk County Pesticide Monitoring Program, May 6, 2004. Talk given by Martin Trent, Office of Ecology, and Sy Robbins, Bureau of Groundwater Resources, at a meeting of Long Island grape growers, held at LIHREC, Riverhead, NY.
  8. Suffolk County Water Authority 2010 Annual Drinking Water Quality Report, www.scwa.com.
  9. Tesic, D., Keller, M., Hutton, R. 2007. Influence of vineyard floor management practices on grapevine vegetative growth, yield and fruit composition. Am.J.Enol.Vitic. 58 (1): 1-11.
  10. Wolf, T. Investigating cover crops as a means of vigor control. In Viticulture Notes newsletter, Sept.-Oct. 2009, vol.24, no.3, Virginia Tech, Winchester, VA.
  11. Wolf, T. Optimized grape potential through root system and soil moisture manipulations: a research update. In Viticulture Notes newsletter, Mar.-Apr. 2011, vol.26, no.2, Virginia Tech, Winchester, VA.
Performance Target:

Performance target: 15 growers adopt mowing and/or green covers under the trellis on a total of 400 acres, reducing leachable nitrate by ≥ 10%, reducing or eliminating herbicides, and reducing canopy management inputs, saving $210/acre while maintaining or improving yield and quality.

 

There was great flux in growers and acreage involved in under vine mowing and cover crops. During the project period, ten growers maintained 43 acres in under vine cover crops. Three growers terminated cover crops plots due to poor establishment and/or changes in management. Five growers practiced under vine mowing, a total of 233 acres in the first two seasons of the project period. Three of five started prior to the project; two of the three terminated mowing by 2015. Two new growers started mowing during the project period. Nitrate leaching in research plots was reduced 20-30% by mowing compared to herbicide plots. Clover increased nitrate leaching as much as 50% compared to herbicide plots while fescue results were similar to those in herbicide plots. Under vine mowing and fescue reduced vine pruning weights from 0-10%, thus canopy management inputs were not reduced as expected; however, yield and fruit quality were maintained.

Cooperators

Click linked name(s) to expand
  • Elizabeth Tarleton

Research

Materials and methods:

Detailed information on methodology and data from research trials will be posted to a dedicated webpage within the CCE-SC grape program website:  http://ccesuffolk.org/agriculture/grape-program/under-vine-management-strategies.

 

The under vine mowing trial was located in a 15 yr old (in 2011) vineyard block cv. Merlot located at the Long Island Horticultural Research and Extension Center, Riverhead, NY. Starting in 2011, the following treatments were implemented.

  1. Under vine mowing 3-5 times annually with a front-mounted single head under vine mower.
  2. Glyphosate (various formulations), 2-3 applications per season.
  3. Mowing 1-2 times, late June glyphosate, mowing 1-2 times.
  4. Mowing 2-3 times, late July glyphosate, no further mowing.

 

An 8 year old (in 2011) commercial vineyard block cv. Syrah located on the North Fork of Long Island hosted the under vine cover crops trial. Treatments included the following:

  1. Glyphosate, 2 applications/season.
  2. Durana white clover, seeded 5 lbs/a.
  3. No Mow fescue mix, seeded at 5 lbs/1000 sq.ft. No Mow fescue mix contained the following fescues: hard, sheep, chewings, red and creeping red.
  4. Combination treatment of clover seeded over fescue mix.

 

Lysimeters, 4 ft. PVC tubes with a ceramic tip, were installed in both trials in order to sample leachate from plots for nitrate analysis.

 

Data collection was similar for both research projects and included the following: weed and cover crop surveys; shoot length; shoot caliper; PQA – point quadrat analysis, used to describe canopy density and architecture; vine pruning weights, a measurement of vine growth the previous season; harvest data (crop weight and cluster number per vine); ripeness indices (Brix or soluble solids which are mostly sugars), TA or titratable acidity, and pH of juice samples; methoxypyrazines and phenolic compounds to gauge ripeness; and nitrate analysis of water samples extracted from lysimeters.

 

Data analysis:  Both trials were laid out in balanced incomplete block designs. Data was analyzed in one way anovas with rows as random effects. Percentage data was log transformed prior to analysis. The Cornell Statistical Consulting unit provided advice on data analysis.

 

Grower demonstration plots ranged in size from 0.02 acres (several panels) to 2 acres in size. We monitored fruit quality for several years and took pruning weights in these blocks. Growers provided management practices including seeding, maintenance, costs, labor requirements and other observations.

 

Economic analyses were created utilizing information generated by the trials as well as costs and practices from industry members particularly the grower advisor group. Herbicide and seed prices were obtained from a local agricultural distributor. Machinery costs were provided by companies as well as local growers. Many cost estimates were obtained from the Cornell publication Cost of Establishment and Production of V.Vinifera Grapes in the Finger Lakes Region of New York, 2013. A Long Island version does not exist. It should be noted that in general the cost of supplies, materials and labor are higher on Long Island. http://publications.dyson.cornell.edu/outreach/extensionpdf/2014/Cornell-Dyson-eb1401.pdf

Research results and discussion:

 

  1. Survey of 100 regional growers – With assistance from regional extension colleagues, we surveyed 46 growers for current practices and interest in alternative strategies. Results were posted to the blog and were utilized by GA group for planning demonstration plots. Completed April 2012.
  2. Webcasts – For the May, 2012 webcast, there were 117 registrants from 21 states as well as Canada, England and Germany. 50 registrants actually tuned in to the webcast about research in Virginia and the Finger Lakes. On April 4, 2015, 50 registered, 24 actually attended a second webcast on perennial and annual cover crops research in the Finger Lakes.
  3. Field tours – Summer 2012 tours of field plots by 20 growers. 11 growers toured mowing trial in September, discussion included grower advisors. 20 Cornell students viewed trials in October, 2012.
  4. Presentations: 30 growers attend presentation at 2013 Viticulture Session of LI Agricultural Forum. Research trial results are presented by educators.  January, 2013, 50 growers from 3 states attended Ag Forum presentation. March– July 2013, 3 grower presentations were given in NY and PA, reaching a total of 92 attendees.
  5. Winter 2013: At least 5 growers interested in implementing mowing/covers will be asked to submit a plan to the GA group for review. There was ebb and flow in the number of growers experimenting with cover crops due to changes in management, failure of cover crop to germinate and lack of attention to cover crop trial.  Two new growers planted cover crops in 2013. Planting advice was obtained directly from grower advisors.
  6. Oct. 2013: Implementation new under-vine mowing and/or green cover plots, summer tours w/ 20 participants as per #3.  In 2013, from July through September, 40 growers viewed cover crops plots. An additional 30 Cornell students viewed the mowing trial. Together with under vine mowing, 276 acres were managed in alternative strategies in 2013.
  7. Winter 2013-14 review as per #4. At least 5 additional growers join the effort in 2014, bringing the total to 15 growers managing 400 acres in alternative under-vine strategies. 27 growers attended a January 2014 grower meeting. For different reasons, 4 growers terminated cover crops trials in 2014. Together with under vine mowing, 169 acres were managed in alternative strategies in 2014.
  8. Follow up verification survey of both participants and non-participants (Long Island) conducted by educators in person, via phone and/or e-mail. 14 Long Island growers were interviewed January – March 2016 to solicit information on seeding, costs, maintenance and vine impacts.
Participation Summary

Education

Educational approach:

One of the goals of this project was to ‘shift the paradigm’ as growers were largely unfamiliar with alternative under vine management strategies. Based on the initial 2012 project survey, under vine green growth was viewed as aesthetically unappealing, more expensive than herbicides and involved additional time and labor for seeding and management. Consequently, one goal of this project was to engage growers in a variety of ways to promote discussions on the topic and to learn the realities of management and costs associated with alternative strategies.

  • Over four seasons, we hosted 13 field tours for 227 growers, though many vineyard managers attended numerous events. A visual introduction to a new strategy was very useful, particularly as site managers explained advantages and disadvantages. We expected field meetings to spur interest in cover crops; unfortunately, that did not occur.
  • Our website, where annual reports were posted, had >2000 hits in both 2014 and 2015. Summaries were also posted on the LIHREC website, though Cornell did not record visits to the site.
  • A 3-year blog (2012-2014) with 35 posts and >1700 page views.
  • We hosted two webcasts, each with speakers from VA Tech and Cornell, with 74 participants.
  • Twelve newsletter articles (4 publications) were written, reaching 3,340 subscribers.
  • Ten PowerPoint presentations were given to 284 people in two states (NY and PA).
  • A new dedicated webpage was created March, 2016, located within the Cornell Cooperative Extension of Suffolk County grape program website: http://ccesuffolk.org/agriculture/grape-program/under-vine-management-strategies.
No milestones

Additional Project Outcomes

Project outcomes:

Impacts of Results/Outcomes

Performance target:  15 growers adopt mowing and/or green covers under the trellis on a total of 400 acres, reducing leachable nitrate by ≥ 10%, reducing or eliminating herbicides, and reducing canopy management inputs, saving $210/acre while maintaining or improving yield and quality.

 

The performance target for this project was partially fulfilled. During the 2012-2013 seasons, under vine mowing and cover crops were implemented in just over 280 acres. This declined to 170 acres by 2015, largely related to the termination of under vine mowing in two vineyards. This was done due to a combination of equipment failure, changes in management or an undesirable decline in vine pruning weights. One grower purchased an under vine mower in 2015. Three growers have a strong interest in under vine mowing but expressed concern about the price of a mower. Under vine mowing is a viable option for under vine management though it is best suited to mature, laser planted vineyards because of the risk of trunk damage to young vines and crooked trunks.

 

Ten growers experimented with clover and/or fescue under the vines. Clover fell out of favor quickly. In one vineyard, it caused a large increase in vine vigor with a concurrent decrease in fruit ripening. Escape weeds were more problematic with clover vs. fescue. White clover grew to about 12 in. but red clover grew to 3.5 ft. tall, obscuring the cluster zone (undesirable for disease management). All growers who tried either white or red clover did not reseed after plots died out in 2-3 seasons. Four fescue plots remain in commercial vineyards. For businesses unable to purchase a mower, fescue is a viable option for reducing excessive vine vigor. Rodents may be an issue with dense stands of fescue. While not a perfect solution, close mowing with a row middle mower would possibly reduce pressure, though this would be costly as it requires two mower passes/row.

 

Environmental benefits realized by this project are important. Herbicides were eliminated on 280 acres of vineyard. Based on other research studies, green cover under the trellis reduces leaching of pesticides and nitrates. This was partially corroborated by lysimeter samples in both trials. Nitrate levels in the mowing trial were 20-30% higher in glyphosate vs mowed plots. In the cover crops trial, nitrate levels were as much as 50% higher in the two treatments with clover compared to glyphosate and fescue plots. When die-back occurred due to drought, nitrogen levels often increased in samples from clover plots. Statistical significance of lysimeter data was inconsistent due to the profound droughts that occurred each summer, limiting the number of lysimeters that provided samples and the dates that samples were obtained.

 

A decrease in vine pruning weights occurred in mowed and fescue plots each season though were statistically significant only in 2013. Growers experimenting with cover crops did not report a concurrent reduction in vine hedging or in cluster zone leaf removal. The reduction in vine pruning weights did not appear to be related to shoot length or shoot caliper but rather to the number and length of lateral shoots (shoot originating in the leaf axil of green shoots) in the upper canopy. Data was not collected to verify this as leaving vines unmanaged would have compromised other aspects of the trial. Based on our own observations as well as that of several growers, mowing and fescue reduced the quantity of foliage removed via shoot hedging but not the number of canopy hedgings required in a season.

 

Reductions in berries/cluster and berry size were expected due to the competitive nature of green covers under vines. This would reduce cluster rot (less compact clusters) and increase quality in reds (higher skin to flesh ratio). In trials and in grower plots, we detected no differences in yield components or in fruit quality indices. There was one exception to this situation. A vineyard compared clover to herbicide treated plots in a block of red varieties situated in a soil with moderate to high soil water holding capacity. In clover plots, there was a sizable increase in vine pruning weights and a decrease in ripeness indices. Berries tasted noticeably less ripe. Again, this block was the exception. In speaking with growers, many felt that the significant periods of drought during the summers of 2012-2015 might have obscured any impacts of green covers on yield and quality. Most growers agreed that vines may react differently to green covers in a season with more frequent rainfall.

Economic Analysis

Gauging the costs of alternative strategies is a challenge due to the large number of variables that can influence the outcome. These figures should therefore be used as an example only. Those interested in mowing or cover crops should develop their own cost analysis to address their particular set of circumstances.

Site preparation

Operation

Labor / hr1

Labor hrs/ a2

Cost

Total

Cultivate under trellis

$20.00

2

$40.00

 

Hand crank seeder

13.50

1

13.50

 

Scratch in w/hoe

13.50

3

40.50

 

 

 

 

subtotal

$94. + seed

OR

 

 

 

 

Glyphosate applic.

20.00

2.6

52.00

 

Hoe out weeds

13.50

5

67.50

 

Hand crank seeder

13.50

1

13.50

 

Scratch in w/hoe

13.50

3

40.50

 

 

 

 

subtotal

$173.50 + seed

1 – Yeh, A., Gómez, M., White, G. 2014. Cost of Establishment and Production of V.Vinifera Grapes in the Finger Lakes Region of New York – 2013. Publ. no. EB 2014-01, Dyson School of Applied Economics and Management, College of Ag and Life Sciences, Cornell Univ. Ithaca, NY, 14853-7801.

2 – Hours gleaned from Yeh, et.al. as well as local growers.

Comments: Two scenarios were developed for seeding based on information provided by local growers. Skilled and unskilled labor rates were used and included fringe benefits. Glyphosate is relatively inexpensive, an application such as this would cost ~ $20 for the material.

 

Seed

 

Cost / lb.1

Seeding rate

Cost per acre

No. seedings over 10 yrs.

White clover

$4.65 / lb

5 lbs/a

$24

3

Fescue mix

2.35 / lb

220 lbs/a

517

1

1 – Source: Long Island Cauliflower Association, Riverhead, NY, the local ag dealer.

 

Comments:  Recommended seeding rates for clover ranged from 2-10 lbs/a. Clover requires re-seeding every 2-3 years. Cornell Cooperative Extension of Suffolk County Weed Scientist Dr. Andy Senesac suggested that a lower seeding rate for fescue might be feasible, as low as 100 lbs/a. Seed prices from the local source were significantly less expensive than those from on-line seed companies. There are quantity discounts for seed, further reducing costs.

 

 

Maintenance – dealing with escape weeds

Operation

Labor / hr

Labor hrs / a

Cost /a

Weed whack or machete tall weeds

$13.50

3

$40.50

OR

 

 

 

Mow 2 passes with row middle mower

20.00

1

20.00

OR

 

 

 

Use high push mower under trellis

13.50

3

40.50

1- Labor rates from Yeh, et.al; labor hours provided by local growers.

 

Comment: Several growers commented that clover required two passes/season to manage escape weeds. Labor estimates varied based on site and row spacing.

 

 

Annual cost of cover crops

 

Site prep

Seed cost / acre

Maintenance

Est. annual cost

/ acre

White clover

$28

$7

$40

$75

Fescue mix

9

24

40

73

 

Comment: Site prep and seed costs were amortized over 10 yrs assuming three seedings for clover and one for fescue. The 220 lbs/a rate of the fescue mix was used. One pass per season was included for maintenance.

 

 

 

Herbicide costs

 

Materials

cost/a2

Labor

Rate/hr3

Labor hrs/a3

Total cost per season / acre

Herbicide regime:

Preemergent1 + glyphosate

& one appl. glyphosate only

$96

$20

4.2

$180

Herbicide regime:

Glyphosate only, two times

18

20

4.2

102

 

1 – Preemergence herbicide Chateau is most common in local vineyards.

2 – Long Island Cauliflower Association, local ag dealer.

3 – Yeh, et.al.

 

 

Equipment

Description

Equipmt.

cost1

Labor hrs

/ acre2

Labor cost / hr

Labor cost

/ acre

Under vine mower, single head1

$3,800

1.5

$20

$30

Under vine mower, two heads w/ row middle mower

15,000

1.5

20

30

Row middle mower2

 

7,800

0.5

20

10

Herbicide sprayer – 50 gal2

2,200

 

2.6

20

52

1 – Various companies were consulted including Fischer Equipment, Italy, and Edwards Equipment Co., Yakima, WA. Some single head mowers require a dedicated frame at additional cost; some can be mounted on existing equipment.

2 – Yeh, et.al.

Comments: Equipment costs can vary widely thus ‘average’ costs were presented. Labor required for under vine mowing depends on the state of the vineyard, row width, presence/absence of crooked trunks, height/density/type of weeds and so on. Based on local estimates, the mower with two heads was driven more slowly than the single head mower.

 

Comparison of costs associated with under vine management regimes

Based on information compiled in preceding charts. Costs are per acre.

Under vine strategy

 

Site prep

 

Materials

 

Labor

Row middle mowing labor

Total cost material + labor

Clover

$28

$7

$40

$40

$115

Fescue

9

24

40

40

113

Single head mower

0

0

120

0

120

Two head mower

0

0

120

0

120

Herbicide 1

0

96

84

40

220

Herbicide 2

0

18

84

40

142

Based on 4 mowings / season both under the trellis and in row middles.

Assuming one head under vine mower is run concurrently with a row middle mower.

For clover and fescue:

  1. Site prep and materials amortized over 10 yrs.
  2. 3 seedings for clover, 1 for fescue
  3. Labor for clover and fescue reflected maintenance costs.

 

Each grower must contemplate the cost : benefit of under vine management strategies. For some growers, the goal of eliminating herbicides trumps all issues with management and equipment costs. For others, the simplicity (no site preparation, no additional maintenance) of herbicides is a necessity especially for growers with a large acreage and/or multiple vineyard properties. Concerns about drought stress, nutritional stress and rodent damage are also valid.

 

The cost and depreciation of equipment was not included in this analysis but weighs heavily as the under vine mower with two heads is very expensive and reportedly requires steady maintenance. While a number of growers have expressed a desire to purchase this type of mower, the cost ($15,000 and up depending on width/configuration), the need to drive slowly and the maintenance have dissuaded some from using this strategy.

Farmer Adoption

Fourteen growers were interviewed as part of a verification survey, half of whom utilized under vine mowing or cover crops. All emphasized a desire to pursue techniques that reduced pesticide use and leachate to groundwater. With the exception of two respondents, all expressed strong support for this project despite management challenges seen in both research plots and grower trials.

Though the project period, a total of 10 growers experimented with cover crop, approximately 43 acres. These were small test plots with the exception of one 2-acre parcel seeded in fescue. Five growers practiced under vine mowing, a total of just over 230 acres the first few years of the project. By 2015, two businesses ceased under vine mowing due to equipment failures while two new growers started mowing. The total acreage involved in alternative under vine strategies, if including growers that practiced weed whacking/close mowing with row middle mowers, was just over 300 acres. By 2015, this declined to 170 acres due to equipment (mower) failure, changes in management and dying out of clover plots.

Consecutive seasons of summer drought were a complicating factor in this project. Plots with under vine green growth tended to exhibit more symptoms of drought stress, even in the presence of drip irrigation. Particularly with under vine mowing and seeded fescue, there were often substantial decreases in vine pruning weights. This would be desirable only where vine vigor was excessive. The two survey respondents that felt herbicides were preferable cited both viticultural (an undesirable decrease in vine size) and economic reasons (expensive mowers) for their preference.

 

Early in the project, there was great enthusiasm for clover as a natural source of nitrogen. This enthusiasm waned due to clover’s sensitivity to drought, unpredictable release of nitrogen, higher maintenance compared to fescue (more escape weeds) and need to reseed every few years. There continues to be interest in under vine fescue as a means of taming vigorous vine growth. Many speculated that the benefits of fescue or mowing might be more substantial in a wet growing season. By project’s end, there was stronger interest in under vine mowing compared to cover crops. One grower purchased a mower in 2015. During verification interviews, three growers expressed interest in purchasing a mower. Only one of fourteen survey respondents planted under vine fescue in 2015.

 

The grower advisors were a highly effective group. We met annually and kept in contact via e-mail and site visits. Strategies for site preparation, seeding and maintenance were compared. The group provided guidance on the season’s research activities. All major research and educational efforts should include this component to ensure relevance of proposed work.

Assessment of Project Approach and Areas of Further Study:

Areas needing additional study

Due to the important environmental benefits of under vine green covers and under vine mowing, future work is warranted. In terms of perennial crops, different fescues should be examined singly rather than in a mix. Because vine water and nitrogen status can be profoundly impacted by covers and mowing, closer examination of those aspects will be important particularly given Long Island’s sandy soils and the prevalence of seasonal summer droughts.

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.