Tree Fruit Growers Move Toward Automation

High-Density Orchard

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Note: The cover story of American/Western Fruit Grower’s April issue featured growers and researchers in Pennsylvania who are involved in a Penn State University Conservation Innovation Grant (CIG) project to develop growing systems that will allow greater orchard mechanization and labor efficiency in the near future. This story highlight some of the technology that is part of this transition to mechanization, and how the state’s apple industry responded to changing market trends in order to make this happen. Much of the information for this article comes from a “Specialty Crop Innovations: Progress and Future Directions” report published by Penn State Extension.

Until recently, nearly three-quarters of Pennsylvania’s apple crop was destined for the processing market. However, as the industry moves toward more fresh-market production, this transition has required a greater focus on fruit quality and getting full production in a quicker period of time.

Increased productivity, however, comes at a cost. High-density orchards require supplemental tree support that adds greatly to their initial investment. Average establishment costs for a high-density block in the Mid-Atlantic region are between $8,000 and $10,000 per acre compared to traditional low-density systems that cost $2,500 to $3,000 per acre to establish. Early and significant yields — a key benefit of high-density production — are critical in achieving maximum economic return and expedited payback in these systems.

The investment is well worth it, however, especially when it comes to future savings in labor. “Transitioning to uniform, high-density orchards will put growers in the best possible position to take advantage of new labor reducing technologies as they are developed,” says Matt Harsh, a fruit and vegetable grower in Smithburg, PA.

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A New Orchard Blueprint

While it is a well-known and generally agreed-upon principle that smaller trees require less labor because they require less pruning and minimize ladder use, few high-density training systems were developed with labor efficiency in mind, and fewer still to facilitate the use of labor-saving mechanization. In fact, Jim Schupp, associate professor of pomology at Penn State’s Fruit Research and Extension Center, has declared at several industry meetings the past few years that fruit growers need to rethink their planting systems and make them more compatible with the potential benefits that mechanized orchard technology can provide.

A few years ago, tree fruit researchers at a fruit production workshop developed a “blueprint” of a successful intensive apple system (the blueprint includes dwarfing rootstocks and high tree density; quality nursery stock; supported canopies; single rows of tall narrow canopies; a canopy shape that complements natural tree form; minimal pruning; and minimal branching structure). In order to be economically productive, the orchard needs to achieve high light interception without creating dense areas in the canopy. Over time horticulturists found that when an orchard system is entirely within the reach of a person on the ground, one of two bad things happens: Either the canopy is productive but too dense, causing a loss of fruit quality, or the canopy is too small, causing loss of yield. The solution has been to increase canopy volume without condensing the canopy by growing the tree taller, while keeping it narrow and orienting the rows in a north-south direction wherever possible to minimize cross-row shading.

According to Schupp, these narrow fruiting wall systems can provide several advantages:
• The tall narrow tree wall is horticulturally sound, and its biological efficiency surpasses the performance of most existing systems.
• Sunlight and labor have the same reach. With narrow canopies, you can address both problems of light distribution and platform labor reach simultaneously.

Once this blueprint was established, the next step was to develop the Conservation Innovation Grant (CIG) project, covered in the April issue of American/Western Fruit Grower. The CIG plantings are evaluating the effect of two high-density apple growing systems on productivity, fruit quality, and labor efficiency. The trees are being trained to form either a continuous tree wall, or a cone-shaped canopy with discrete gaps in the tree tops. Labor efficiency between the two systems is being compared using both ladders and a mobile platform. The large number of CIG trials and the relatively large size of the plantings will also provide adequate space for evaluating additional labor saving technologies developed through two USDA Specialty Crop Research Initiative (SCRI) projects funded in 2008. By blending this research into the CIG demonstration project, researchers hope to increase the visibility of the results and speed industry adoption of new practices as they develop.

To watch videos of Jim Schupp, as well as Pennsylvania fruit grower Bruce Hollabaugh, discussing how CIG plantings will benefit the apple industry,.

To learn more about the technology being developed for these systems, go to the next page of this story.

Trialing Technology

Trials with an orchard platform prototype were conducted in 24 Pennsylvania orchard blocks during 2006 to 2007. Tree architectures included peaches trained to perpendicular V and apples trained to vertical axis. The purpose of taking the orchard platform to as many orchards as possible was two-fold — the research team could evaluate platform efficacy with various modifications of tree training systems, and growers would have the opportunity to assess where tree training and plant spacing adjustments should be made for improved adaptation to automation. An added benefit of commercial orchard trials was that growers and employees provided valuable feedback on possible future directions for team research.

Worker productivity with the moveable platform compared to ladders increased by an average of 35% for peach thinning and pruning and 50% for peach harvest and apple thinning, tree training, or pruning. Task times per acre with ladders ranged from 11 hours for tree tying and pinching to 90 hours for apple thinning, and with the orchard platform ranged from six hours for tree tying and pinching to 51 hours for apple thinning. The platform was more efficient than ladders for all tasks.Some growers have built their own platforms and others have used semi- autonomous platforms with harvest assist capabilities from Washington or directly from Europe.

In addition, Carnegie Mellon University has automated a model of an Italian platform that is being evaluated by Penn State. Through the “Comprehensive Automation for Specialty Crops” SCRI project, Carnegie Mellon engineers led by Dr. Sanjiv Singh have also added sensor technology to these platforms.

In tandem with mobile platforms, the use of harvest-assist technology is also being addressed. Knowing that sensitive fruit handling has long been a stumbling block, Carnegie Mellon and Penn State once again teamed up to evaluate bin filler prototypes. During the initial year of this project, two passive bin filler prototypes showed promise in laboratory tests to assess potential reductions in damage to fruit during the bin filling process.

Current efforts focus on integrating an apple transport system with a bin filler design, so that fruit are singled out upon picking all the way to the bin. In 2010, the project team began working with a commercialization partner, DBR Conveyor Concepts in Conklin, MI, on a vacuum tube transport system and automated bin filler that can be retrofitted to existing grower equipment. For Penn State trials, the harvest system was adapted to the orchard platform automated by Carnegie Mellon.

More Information

Check out the Comprehensive Automation for Specialty Crops website (www.cascrop.com) for more background on mobile platforms and harvest-assist technology. The “What’s New” section includes videos of autonomous harvester trials in Washington (part of a multi-state trialing system) as well as a vacuum assist harvester.

For more information on innovative thinning technologies, go to www.abe.psu.edu/scri. The latest video update highlights automated positioning of the Darwin string thinner, which is being evaluated as part of another multi-state project.

Aside from videos, each of these sites has updated reports on the latest research from across the country.

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