INNOVATIVE TECHNOLOGIES FOR THINNING OF FRUIT

NON-TECHNICAL SUMMARY: Labor utilization and availability is of great concern to specialty crop growers. The current decrease in available labor for orchard operations and the potential for further reductions in the near future requires innovative solutions in the areas of sensor technology applications, mechanization, automation, and robotics. Many of the current labor-intensive activities required in the management of specialty crop production will need to be replaced by more mechanized and automated techniques. Fruit thinning is one such application of mechanization, advanced sensor technologies, and robotics. The blossoms or fruitlets of fruit trees must be thinned to enhance the size of the remaining fruit. Traditionally, thinning has primarily been accomplished through the use of hand labor. Thinning also has been induced by chemical means or just simply allowing the thinning to take place naturally, for example, as a result of a light frost or as natural `June drop. The availability and efficacy of chemical thinning programs varies by crop, orchard, and season, so follow-up hand thinning is often required to adjust crop load for optimal fruit size, quality, and to promote return bloom. This is particularly true for stone fruit and organic apple and pear production, where chemical thinning options are limited. Due to the many limitations of current thinning methods, the USDA "Engineering Solutions for Specialty Crop Challenges" workshop report lists mechanical fruit thinning as a top priority (3 on a 0 to 3 scale) for mechanization. This project will address the mechanized thinning engineering challenge through five clearly defined objectives. The objectives include addressing tree architecture to enhance mechanized thinning, significant engineering modifications to two prototype non-selective mechanical thinners, development of more advanced, sensor-based thinning equipment, field testing of both non-selective and sensory-based technology through cooperating grower sites, interaction with equipment developers, and evaluation of environmental, sociological, and economic impacts on producers and field production. The projected impacts of reduced labor requirements and targeted fruit loads are increased production efficiency, profitability, environmental stewardship, and social responsibility in specialty crop systems. Additional implications for growers and rural communities include the enhanced sustainability of family farm enterprises that sell locally to consumers, the enhanced sustainability of farm enterprises that compete on the global market, the benefits of stabilization of local workforces (reducing the number and degree of peak labor demands across the year), the preservation of prime farmland, and the revitalization of rural communities.

OBJECTIVES: Tree fruit is thinned at the blossom or early fruit development stages to ensure larger, higher quality product. This management practice, typically performed by hand, is a labor-intensive and expensive activity. Development of methods to mechanize thinning is a top priority for the tree fruit industry. This project will develop and test new mechanical thinners. A new string thinner will be developed with capability to operate in both vertical and horizontal orientation and evaluated in both traditional and high density training systems. A new drum shaker prototype for green fruit thinning with design features based on previous testing of mechanical harvester prototypes will be evaluated for thinning efficacy, ease of operation, and reduced potential for tree damage. Tree canopy parameters will be studied to enhance machine access to the target blossoms or fruit, and to facilitate machine vision for use with precision end effectors for selective fruit thinning. Sensors will be used to detect the trees and control the position of the thinner relative to the canopy for maximum efficacy and tree safety. Machine vision combined with novel precision end effectors will be developed and tested for selective thinning. The trans-disciplinary project team includes engineers, horticulturists, economists, sociologists, and extension educators. This team will work closely with stakeholders in the tree fruit industry, and results of the effort will immediately be available to commercial operations for implementation. The importance of the work to the tree fruit industry is indicated by the strong financial support being provided by the industry.

APPROACH: The trans-disciplinary goal is to develop and field test novel mechanized methods of thinning specialty crops and to assess sociological implications and economic feasibilities of industry implementation. A multi-disciplinary team will investigate approaches that integrate electronics, mechanical components, and decision making algorithms to provide efficient, cost-effective, and ecosystem-based fruit thinning. These objectives include both research and extension components, and provide for industry interaction to address the many issues involved in the development to delivery process. Additionally, due to regional differences in fruit cultivars, equipment usage, and tree training systems, a multi-institutional approach will be developed to address device modifications needed for specific regions. Specific objectives include: 1) Integrate mechanization and tree canopy architecture (as growing systems evolve from a three-dimensional to two-dimensional structure) by investigating training modifications to make flowers or fruit more visible/accessible and new methods of targeting optimum level of crop load adjustment at various stages of bloom/fruit development. 2) Further develop and modify two prototype non-selective fruit thinning devices to improve prototype efficacy, commercialization potential, and the opportunity for immediate adoption by an industry that is actively seeking engineering solutions for the near term. 3) Develop and integrate electronic and mechanical technologies for higher precision and selective thinning. 4) Provide technology transfer by pilot testing prototype units from Objectives 2 and 3 in orchards with commercial growers, and work with industry towards commercialization of thinning units. 5) Evaluate sociological implications and economic impact of implementation of mechanized fruit thinning devices by comparing traditional approaches with new mechanized approaches developed and tested in previous objectives. Data will be analyzed using appropriate standard statistical methods with replicated trials. Comparisons and conclusions will be drawn from non-thinned and hand-thinned control treatments conducted under the same conditions as mechanical thinning treatments. Detailed production-based data will be collected, including the evaluation of crop removal, fruit set, follow-up hand thinning requirement, yield, and fruit quality in commercial orchards with the help of grower cooperators. These data will be analyzed using appropriate standard statistical methods with replicated trials. Results will be interpreted by the project scientists, and socio-economic impacts will subsequently be assessed by team economists and extension educators working with university sociologists. Significant findings will regularly be presented for review by the project advisory panel. The input of grower cooperators and advisory panel members will assist the research team to assess and interpret results to the maximum benefit of the specialty crop industry.

PROGRESS: 2009/09 TO 2010/08

OUTPUTS: "Innovative Thinning" project activities focused on further testing and modification of non-selective mechanical thinner technologies, field trials to assess horticultural and economic benefits of non-selective thinning, further development of selective thinning components, outreach demonstrations and publications to promote technology transfer and commercialization, and reports for advisory panels and other stakeholder groups. Washington State thinning trials with two string thinners were featured in 9 outreach events. Replicated on-farm trials included 3 sweet cherry, 3 apple, 1 apricot and 1 nectarine. On-farm demonstrations included 1 pear and 1 apricot. A new hand held string thinner was tested in 7 sweet cherry trials. 725 people attended the outreach events. California had 10 replicated trials in cling peach and 20 demonstrations or grower run trials. One of the grower trials was on pears; the others were in cling or fresh market peach. Three string thinner units were used in these trials. 80 people attended the various demonstrations. South Carolina trials were conducted on 3 grower farms (2 with traditional open center trained trees and the other with a high-density quad-V system). Alternative orientations of the string thinner, e.g., over the top and side/vertical, were tested in the open center systems. Outreach events reached an estimated 85 participants representing 18,000 acres. Pennsylvania had 6 replicated trials with the string thinner and 2 with a USDA drum shaker with a new rod displacement system to improve thinning efficiency and reduce trunk damage. String thinner trials focused on string pattern arrangements and an automated positioning system to improve uniformity of thinning. 300 growers representing 20,000 acres attended presentations. Selective thinner development included further machine vision testing, laser range finding, and image analysis of peach trees both in the lab and in the orchard. Two end effector blossom removal mechanisms were designed and one was fabricated and tested by hand. Further design details on the second mechanism have been developed. Two used FANUC M-16 industrial robots were purchased and delivered to the University of Illinois and Penn State. These will provide the positioning of the blossom removal mechanisms guided by the vision system. Demonstrations and presentations were held at 42 extension outreach, industry conventions, and professional conferences, including the Cumberland-Shenandoah, Washington State Horticultural, Sacramento Valley Cling Peach, California Cling Peach Industry, Illinois Specialty Crops, Ohio Produce Growers and Marketers, USDA Systems, SE Fruit and Vegetable, South Georgia/North Florida and South Carolina Peach, National Peach, Mid-Atlantic Fruit and Vegetable, International Fruit Tree Association, Nuffield International Farming Scholars, New Jersey Tree Fruit IPM, American Society for Horticultural Science, and NE Agricultural and Biological Engineering meetings. Additional outreach efforts included trade journal articles, videos, powerpoints, extension bulletins, and posters that are available at the project web site (http://www.abe.psu.edu/scri/). PARTICIPANTS: Project Members: Director: Paul Heinemann, Professor, Agricultural and Biological Engineering, The Pennsylvania State University; Tara Baugher, Tree Fruit Extension Educator, The Pennsylvania State University, Adams County Cooperative Extension; Michael Delwiche, Professor, Biological and Agricultural Engineering, University of California-Davis; Tony Grift, Associate Professor, Agricultural and Biological Engineering, University of Illinois; Jayson Harper, Professor, Agricultural Economics and Rural Sociology, The Pennsylvania State University; Karen Lewis, Tree Fruit Area Extension Educator, Washington State University Extension; Jude Liu, Assistant Professor, Agricultural and Biological Engineering, The Pennsylvania State University; Marvin Pitts, Associate Professor, Biological Systems Engineering, Washington State University; Gregory Reighard, Professor, Horticulture, Clemson University; James Schupp, Associate Professor, Horticulture, The Pennsylvania State University Fruit Research and Extension Center; David Slaughter, Professor, Biological and Agricultural Engineering, University of California-Davis; Yang Tao, Professor, Biological Engineering, University of Maryland; Christopher Walsh, Professor, Plant Science, University of Maryland; Cooperators: Stephen Miller, USDA-ARS Appalachian Fruit Research Station; Scott Johnson, University of California Kearney Agricultural Center; Roger Duncan, University of California Extension; Janine Hasey, University of California Extension; Greg Henderson, Clemson University, Katie Ellis, Penn State Extension; Jim Remcheck, Penn State Extension; Edwin Winzeler, The Pennsylvania State University Fruit Research and Extension Center. Partner Organizations: USDA; Washington Tree Fruit Research Commission; California Canning Peach Association; State Horticultural Association of Pennsylvania; Pennsylvania Department of Agriculture; South Carolina Peach Council. Training: student participants Clemson University: Will Henderson Penn State: Russell Rohrbaugh, Tom Kon, Robin Pritz, David Lyons; Carnegie Mellon: Matt Aastad; Millersville: Celine Kuntz; Grove City College: Evan Moore; McDaniel College: Jennifer Rouzer; Madison University: Ryan Hilton; Oberlin College: Amelia Jarvinen; Modesto Jr College: Rose Lorenzo TARGET AUDIENCES: Fruit growers, particularly tree fruit throughout the U.S. and Canada; Potential commercial developers of machinery PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

IMPACT: 2009/09 TO 2010/08

WA - Repeated field trial results in both apricot and nectarine have shown that with correct timing and application, string thinner that reduces bloom and subsequent fruit set and increases final fruit size. Increase in final fruit size in mechanically thinned blocks is equal to that measured in hand bloom thinned trees. The 2010 cost for hand bloom thinning ranged from $540 to 750 per acre. Mechanical thinning was estimated at $40 to 60 per acre. Green fruit thinning in string thinned nectarine and apricot blocks was reduced by 40 to 50% when compared to green fruit thinning alone. There was no initial significance in green fruit thinning time or corresponding costs between mechanically thinned and hand blossom thinned trees. With positive results in stone fruit trials for 3 years, Blueline Manufacturing in Moxee, Washington became a Darwin string thinner distributor in the summer of 2010 and 2 machines were ordered. Interest in mechanical thinning in apple, pear and cherry is increasing. Mixed results in cherry led to securing $100,000 in industry funds to develop a hand held string thinning device. This is an example of leveraging SCRI funding and the development of a new collaboration with WSU CPAAS and the University of Chile. CA - In the 10 replicated trials on cling peach, generally positive results were found with the string thinner. All 10 experiments showed an increase in fruit size at the time of hand thinning and/or harvest. Seven of the 10 required less hand thinning which saved the grower anywhere from $200 to $500 per acre. About half of the trials had increased yields of 0.5 to 3.1 tons/acre. However, several lost 2 to 4 tons. Overall, most of the trials showed increased profitability of anywhere from about $200 up to nearly $1000 per acre. The few that lost money were generally due to varieties that set poorly in 2010. Interest in California is increasing, especially among cling peach growers. One grower purchased a unit and another made his own. One fresh market peach grower also purchased a unit. SC - Data from 2010 peach trials on the open center system suggested an overall cost reduction in green fruit thinning of $85 to 93 per acre compared to the grower standard hand bloom thinning, with a corresponding increase in gross revenues based on size distribution of $236 to 479 per acre. Relocation of the flow valve permitted improved tree canopy access. PA - A 6 column helix string arrangement compared to a 2 column 9 string arrangement increased thinning uniformity in 1 out of 3 trials. A string thinner modified to automatically adjust to canopy width and angle increased thinning efficacy and uniformity, and the thinner manufacturer plans to model a new thinner based on the Penn State prototype. Eight string thinners were purchased in 2010 by NE growers, and all reported reduced labor requirement. The drum shaker reduced crop load and follow-up hand thinning time significantly over a conventional hand thinning technique only when operating at 300 to 400 cycles per minute. Preliminary data suggest bark damage was less than obtained with previous prototypes, but damage was not eliminated, which is one of the ultimate goals.

PUBLICATIONS (not previously reported): 2009/09 TO 2010/08

1. Ellis, K. 2009. Developments in Technology and Automation for Tree Fruit. Proc. Great Lakes Fruit, Vegetable, and Farm Market Expo, Grand Rapids, MI. Tree Fruit Session. pp. 4-7.

2. Baugher, T. A., J. Schupp, K. Ellis, J. Remcheck, E. Winzeler, R. Duncan, S. Johnson, K. Lewis, G. Reighard, G. Henderson, M. Norton, A. Dhaddey, and P. Heinemann. 2010. String blossom thinner designed for variable tree forms increases crop load management efficiency in trials in four U.S. peach growing regions. HortTechnology 20:409-414.

3. Schupp, J., P. Heinemann, T. Baugher, S. Miller, J. Liu, R. Dise, and A. Leslie. 2010. Innovative technologies for thinning of fruit. 2010. Ohio Produce Growers and Marketers Association Today. Pataskala, OH. pp. 6-9.

4. Schupp, J., T. A. Baugher, R. Crassweller, K. Ellis, E. Winzeler, J. Remcheck, and T. Kon. 2010. Labor efficient production systems. PA Fruit News 90(2).

5. Baugher, T. A., J. Schupp, P. Heinemann, S. Miller, K. Ellis, E. Winzeler, K. Reichard, J. Remcheck, C. Musselman, A. Leslie, R. Rohrbaugh, S. Wolford, M. Schupp, C. Kuntz, E. Moore, J. Koan, C. Anders, and T. Kon. 2010. Innovative technologies for thinning fruit. PA Fruit News 90(3):20.

6. Emery, K. G., D. M. Faubion, C. S. Walsh, and Y. Tao. 2010. Development of 3-D range imaging system to scan peach branches for selective robotic blossom thinning. ASABE Paper number 10-09202. The American Society of Agricultural and Biological Engineers. St. Joseph, MI. 10 pp.

7. Heinemann, P., J. Schupp, and T. A. Baugher. 2010. Innovative technologies for thinning of fruit. HortScience 45(8):S199 (Abstract).

8. Schupp, J., T. A. Baugher, K. Ellis, J. Remcheck, E. Winzeler, R. Duncan, S. Johnson, K. Lewis, G. Reighard, G. Henderson, M. Norton, A. Dhaddey, and P. Heinemann. 2010. String blossom thinner designed for variable tree forms increases crop load management efficiency in trials in four peach growing regions. HortScience 45(8):S199 (Abstract).

9. Kon, T. M., W. E. Winzeler, and J. R. Schupp. 2010. Golden Delicious cropload adjustment with the Equilifruit disk. HortScience 45(8):S256 (Abstract).

10. Baugher, T. A., J. Schupp, K. Ellis, E. Winzeler, J. Remcheck, K. Lesser, and K. Reichard. 2010. Mechanical string thinner reduces crop load at variable stages of bloom development of peach and nectarine trees. HortScience 45(9):1327-1331.

PROGRESS: 2008/09/01 TO 2009/08/31

OUTPUTS: Innovative Thinning project activities focused on non-selective mechanical thinner modifications to increase adaptation to variable tree architectures, developing and integrating electronic and mechanical technologies for selective thinning, field trials to assess horticultural and economic benefits of non-selective thinning, outreach demonstrations and publications to increase technology transfer and commercialization, and reports for advisory panels and other stakeholder groups. Trials with the mechanical blossom string thinner were performed Spring 2009 in 13 PA, 3 SC, 8 WA, and 4 CA commercial and research orchards. The USDA drum shaker was tested in 3 PA orchards during the bloom and green fruit stages. Conventional hand thinning at the green fruit stage was the control treatment. Varying operational speeds, blossom stages, and pruning modifications to improve access by the thinner were assessed. Data were uniformly collected across all regions to determine blossom removal rates, fruit set, labor required for follow-up hand thinning, fruit size distribution at harvest, yield, and economic impact. Case study interviews of 11 growers and orchard managers were conducted to assess sociological implications relative to stakeholder adoption. These growers had cooperated in trials on a total of 154 acres. Selective thinner development included machine vision testing, laser range finding, and image analysis of peach trees both in the lab and in the orchard. Design criteria for selective thinning were developed based on blossom identification and removal force assessments. Demonstrations and presentations were held at 21 extension outreach and industry conventions, including the SE Peach Convention, CA Peach Canning Conference, WA Horticultural Convention, Mid-Atlantic Fruit & Vegetable Convention, Ontario Fruit & Vegetable Convention, NY Fruit & Vegetable Expo, Cornell Extension Fruit School, Clemson Fruit Producer Meeting, New Zealand Summerfruit Meeting, Penn State Engineering Solutions Workshop, Penn State Fruit Research & Extension Center Field Day, Clemson Research Center Peach Field Day, WA Fruit Research Field Day, UC Davis Thinning Field Days, UC Kearney Research Center Thinning Demonstration, Penn State Workshop on Tree Architecture for Mechanization, Penn State Spotlight on Peach Thinning, and Pacific NW Engineering Solutions Workshop. Additional outreach efforts included the production of videos, powerpoints, extension bulletins, and posters that are available at the project web site (http://www.abe.psu.edu/scri/). Twenty-five outreach stories were circulated through trade magazines and newspapers, including the Good Fruit Grower, Cling Peach Review, Ag Alert, Fruit Grower News, American Fruit Grower, and Peach Times. The project advisory panel met during the Mid-Atlantic Fruit & Vegetable Convention and is regularly updated by list-serve reports and timely updates at the web site. Team members also were invited to give special presentations to 8 stakeholder organizations, including PA legislators, the PA Fruit Industry Task Force, CA Peach Canning Association, WA Tree Fruit Research Commission, and Horticultural Association of PA. PARTICIPANTS: Individuals: Project Director: Paul Heinemann, Professor, Agricultural and Biological Engineering, The Pennsylvania State University; Tara Baugher, Tree Fruit Extension Educator, The Pennsylvania State University, Adams County Cooperative Extension; Michael Delwiche, Professor, Biological and Agricultural Engineering, University of California-Davis; Tony Grift, Associate Professor, Agricultural and Biological Engineering, University of Illinois; Jayson Harper, Professor, Agricultural Economics and Rural Sociology, The Pennsylvania State University; Karen Lewis, Tree Fruit Area Extension Educator, Washington State University Extension; Jude Liu, Assistant Professor, Agricultural and Biological Engineering, The Pennsylvania State University; Marvin Pitts, Associate Professor, Biological Systems Engineering, Washington State University; Gregory Reighard, Professor, Horticulture, Clemson University; James Schupp, Associate Professor, Horticulture, The Pennsylvania State University, Fruit Research and Extension Center; David Slaughter, Professor, Biological and Agricultural Engineering, University of California-Davis; Yang Tao, Professor, Biological Engineering, University of Maryland; Christopher Walsh, Professor, Plant Science, University of Maryland; Stephen Miller, Research Horticulturist, USDA-ARS Appalachian Fruit Research Station, Kearneysville, WV; Scott Johnson, Kearney Agricultural Center, CA; Roger Duncan, UC-Davis; Katie Ellis, Penn State Extension, Jim Remcheck, Penn State Extension. Partner Organizations: USDA Washington Tree Fruit Research Commission; California Canning Peach Association; State Horticultural Association of Pennsylvania; Pennsylvania Department of Agriculture; South Carolina Peach Council. Training: student interns: Penn State: Alex Leslie, Russell Rohrbaugh; Michigan State: Jacob Koan; Kalamazoo College: Cody Musselman; Graduate student: Reuben Dise. TARGET AUDIENCES: Fruit growers, particularly tree fruit throughout the US and Canada; Potential commercial developers of machinery PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

IMPACT: 2008/09/01 TO 2009/08/31

String thinner trials to assess optimum operational parameters for varying growing regions and tree forms showed reduced labor costs compared to hand thinned controls and increased crop value due to a larger distribution of fruit in higher market value sizes. Blossom removal ranged from 20-55%, hand thinning requirement was reduced by 25-65%, and fruit size distribution improved in all but one trial. Net economic impact at optimum tractor and spindle speeds was $462-$1490 and $230-$847 per acre for processing and fresh market peaches, respectively. Trials with the string thinner at varying bloom stages showed the thinning window is from pink to petal fall. Trials on modifications in tree training to improve access by the string thinner indicated detailed pruning for targeted crop loads was superior to standard pruning. Studies with a new drum shaker prototype adapted from a blackberry harvester demonstrated increased thinning consistency compared to previous research with a citrus drum shaker. Yield was reduced in some fresh fruit trials, and future trials will address this concern. Several combination treatments, including the string thinner + hand blossom thinning, the string thinner + the drum shaker, and string thinner treatments on both the sides and tops of tree suggested additional strategies for achieving the most desirable thinning results. Experiments for selective thinning validated 3-D and UV imaging precision and established force required to remove blossoms (avg. 0.10 lb). All the growers who agreed to participate in case study interviews indicated the string thinner impacted orchard management by making crop load management more efficient and by reducing follow-up hand thinning time. Eighty percent of the growers noted fruit from trees that had been thinned were larger. Observations included the following: hand thinning of peaches completed earlier allowing more timely work in other crops, employee satisfaction with thinners as they saved them time and minimized ladder use, improved work load distribution. Of the stakeholders who were surveyed following the workshop on tree architecture for mechanization, 78% indicated workshop outcomes included planting new competitive orchard systems at higher tree densities and adopting peach pruning and training strategies for better targeting crop load. Horticulture conference participants surveyed following a technology session rated thinning and harvesting as the areas of greatest need to improve precision and efficiency in orchard enterprises. On-farm trials demonstrating management benefits were noted to be effective tools for encouraging technology adoption. Five refereed papers have been published in journals such as HortTechnology and HortScience. Professional papers were presented at the NE Agricultural and Biological Engineering Conference and the ISHS Precision Agriculture Conference. The new peach tree thinner version of the string thinner (PT250) developed specifically for this project has been commercialized and will now be manufactured in North America. Distributors have been identified in CA and PA.