Apr 7, 2007

Adams County Looks at Platforms for Mechanization

Adams County, Pa., with its long history of fruit culture, in many ways epitomizes what is right and what is wrong with fruit production in the United States today.

So it seems appropriate that Adams County is taking the lead with a project that could have broad application in re-tooling fruit production in the mid-Atlantic states. It’s called the Adams County Ag Innovation Initiative.

Last summer, a group of Penn State researchers, Adams County Extension personnel and growers teamed up to investigate what might be done to mechanize some of the more labor-intensive parts of fruit production. They worked to customize and hone a motorized, self-propelled worker platform that could replace ladders, which, according to the project leaders, “make pruning, thinning and harvesting inefficient and costly.”

“The research team collected some excellent data in commercial orchards on labor efficiency improvement,” said Phil Baugher, co-chairperson of the Ag Production Innovation part of the three-part initiative. “The team saw a 40 to 60 percent improvement in workforce productivity for peach and apple thinning.”

That, he said, is exciting.

“What else can we do that would make a 40 percent improvement in efficiency?” he asked. “Half of the cost of producing fruit is labor, so we’re making a big improvement in a very big cost area.”

Baugher, whose family is involved in fruit production as well as the fruit tree business, makes a perfect spokesman. Besides being a co-chair of the Adams County Ag Production Innovation effort, he has served on the steering committee for the National Tree Fruit Technology Roadmap Initiative.

The Technology Roadmap study group concluded that, to remain competitive in fruit production, United States producers will have to lower their costs of production by 30 percent by the year 2010, and reducing labor costs was the top item on the list of ways to achieve that.

So, the Adams County folks are on the right track, or at least the same track.

Producers East and West face different challenges in growing and marketing fruit. The Adams County Ag Innovations group identified three overall areas of concern -– one involving land use and urban sprawl, a second involving creating an identity for the marketing of Eastern fruit, and the third relating to production innovation.

“Adams County has a rich heritage of agricultural productivity and stewardship,” said Katy Lesser, who is the Ag Innovations Coordinator in the Extension office in Adams County. “We are fortunate to have a strong base of natural resources, infrastructure and support industries that are necessary to promote a dynamic farm economy. Yet from all angles, agriculture is pressed and facing an uncertain future.”

Research team leader and Penn State pomologist Tara Baugher explained that time trials comparing the moveable platform and ladders were conducted in 10 commercial orchards on peaches trained to the perpendicular V system and apples trained to the vertical axis.

“Worker productivity with the moveable platform compared to ladders increased by an average of 13 percent for tree training, 36 percent for peach thinning, 50 percent for apple thinning and 59 percent for peach harvest.”

Modifying the platform

Over the course of the study, the platform was redesigned to incorporate lessons learned -– to improve the performance of the platform and improve worker comfort. What started as a two-level, tractor-towed platform with side safety rails on each level evolved into a self-propelled, two-level platform without side rails and workers using safety harnesses. Extensions were added to either side of the decks to conform to alley widths, designed so that workers could get close to their work.

“In our trials, we’ve learned a lot about what works on platforms and what doesn’t,” said Dan Rice, one of two student engineers working on the project.

When the platform was purchased in May, it looked a lot different than it did in August, when about 60 growers gathered at an orchard in Benderville, Pa., to watch it in action.

The starting point was a Northstar platform from Rankin Equipment Co. in Yakima, Wash.

Initially, it was two platforms – a lower deck and an upper deck – on one frame that could be adjusted to different heights and widths with removable railings on both sides. It could either be pushed or pulled by a tractor. The research team found that by removing the railings and harnessing workers to a bar in the middle, they could increase reach and mobility and reduce back pain caused by leaning.

Fewer people on the platform were more effective than loading it to its maximum capacity. The platform was most effective, Rice said, when workers could work on both sides, on two rows of trees, with alleys the proper width and the trees designed and pruned so workers could reach tree centers about 2 feet away.

Efficiency was increased further by eliminating the tractor driver. A self-propelled undercarriage was engineered for the platform, which was steered from the first level by a worker. A creeper gear provided for constant movement down the rows.

Team economist and co-research team leader Matt Harsh said that, “even with conservative estimates, by our calculations there was a cost difference in favor of the platform in most of the orchards. Where we didn’t see a cost benefit was in situations where the tree architecture or block design was not conducive to mechanization.”

It was easier to work from a platform than from a ladder, he said, and workers seemed to do a more thorough job of thinning.

Slope steepness is one characteristic that separates Eastern orchards from those in the West. The platform was quite stable and worked better moving up and down slopes. Side slopes tipped workers into or away from their work.

Much of the orchard work was done by the researchers themselves and with summer interns, including Ben Wenk, Sarah Waybright, Matt Tindall and Ryder Musselman.

“Workers and managers seemed to like the platform,” said Lesser, the project coordinator.

She said the platform expands the potential pool of workers because the work isn’t as physically demanding and could allow people who haven’t wanted or been able to do orchard work to do it.

Sarah Waybright, a horticulture summer intern, reported that the harnesses were an improvement over the railings. Workers leaning over the railings reported pelvic soreness and back pain, and the railings themselves sometimes damaged tree limbs.

Orchard design

The orchard system that works best with platforms is the one that is best for growing fruit, according to Penn State pomologist Jim Schupp.

“For a long time, people thought that the photosynthethic rate of leaves closer to the trunk of the tree was lower because they were being shaded by leaves further out on the branches and just not getting enough light,” he said.

“We found that even with similar light levels, those leaves don’t photosynthesize as well. Because they form in the shade, they have fewer cells in the palisade layer where the chloroplasts that do photosynthesize exist.”

Ideal tree training that makes use of this finding involves keeping limbs short, 2 to 3 feet, and uniform up the trunk. This is the kind of tree that can be best worked with from a platform, whereas the central leader tree with its longer lower limbs is much harder to approach with a platform.

For maximum light interception and orchard productivity as well as ease of mechanization, trees should be 10 feet to 12 feet tall with narrow, conical canopies, Schupp said.

In peaches, trees trained to the perpendicular V seem to fit the platform extremely well. The trees are wider at the top than the bottom – the opposite of apples – matching the shape of the platform, which can be adjusted so it is narrower at the top and wider at the bottom.

Harvesting studies

Peaches and nectarines from perpendicular V systems were harvested directly into half-bushel crates or into half-bushel picking buckets and then bins. The lower deck of the orchard platform was modified to accommodate a pallet or bin and shelves were built to support the crates and buckets at a convenient height.

Given the importance of properly harvesting the fruit, orchard employees rather than the ag innovations crew were timed in these investigations. Harvest times per acre averaged 10 hours for the platform and 23 hours for ladders. A number of Pennsylvania growers sell peaches in half-bushel crates, and the platform eliminated excessive handling of fruit.

Jackie Van Pelt, a summer engineering intern, worked on bin filler designs for use with apples. The most promising and innovative design developed was the false floor bin filler. A bin-sized single layer of apples would be accumulated on a shelf constructed of parallel rods. When full, the layer would descend into the bin until a sensor indicated that the layer was directly over the bottom of the bin or the highest layer of apples. The floor of the layer, composed of evenly spaced rods, would then “disappear” by sliding underneath one another and the new layer of apples would be deposited onto the previous layer.

“The process of determining how best to retool an industry involves evaluating where efficiencies can be gained,” Tara Baugher said. “Our research comparing platform and ladder efficiencies for four labor-intensive orchard tasks indicates that worker productivity can be improved by 10 to 60 percent, with the greatest gains occurring in thinning and harvest operations.

“We have yet to evaluate dormant pruning but expect similar results. Fruit growers in the mid-Atlantic region are developing their own modifications of orchard platform technology and comparing costs and benefits. Ultimately, the greatest leaps in innovation will come from growers who adopt total systems approaches to orchard management.”