AgBioResearch

Michigan is the No. 1 producer of tart cherries in the United States and a major contributor to worldwide production.  A team of researchers led by Michigan State University (MSU) AgBioResearch scientist Ron Perry believes that this long-standing status is in jeopardy and that maintaining the industry’s competiveness requires a change in harvesting and production systems.

“The current tart cherry mechanical harvesting system consists of a trunk shaker and fruit- catching frame that restricts plant density by requiring widely spaced rows and large trees,” said Perry, an MSU Extension specialist and a professor in the MSU Department of Horticulture. “This arrangement restricts tree density to a maximum of 240 trees per acre. New tart cherry orchards in Poland and Germany are being planted at 1,150 trees per acre.”

Improper operation of trunk shakers often damages trees and reduces orchard longevity. Many viable and productive orchards last no longer than 20 years. In addition, growers cannot harvest orchards until the trees are five to six years old to reduce the potential for mechanical damage to the trunks by the shakers.

The research group also believes that radical -- rather than incremental -- modifications in key tart cherry production systems are critical for Michigan’s tart cherry industry.

“Given the limitations of the current harvesting system, the Michigan industry could be at risk of being surpassed because less advanced countries have modernized and been innovative,” Perry said.

The research group is recommending changing harvesting technologies, improving fruit quality through genetics, establishing novel tree formations, and implementing high-density orchard designs. Perry and his team believe that these changes will create the potential to improve competitive returns to Michigan growers.

For this project, over-the-row berry harvesters were tested on compact seedling tart cherry selections at the Clarksville Research Center, one of 14 MSU AgBioResearch centers located across the state. The test determined that at least one harvesting mechanism currently on the market – the “Rotary-tine Tower” berry harvester -- removed fruit at an efficient rate and without tree or fruit damage.

For effective use of this harvester, however, cherry trees need to be smaller and more compact than traditional tart cherry trees. Studies are under way to identify approaches to maintain compact canopies of the traditional Montmorency tart cherry variety and to test possible new varieties. The fruit of these varieties has to be acceptable to the processing industry, and the trees must remain small and compact enough to accommodate the harvesting equipment.

Several field research plots have been established at the Northwest Michigan Horticulture Research Center (another AgBioResearch center) near Traverse City, Mich. The first plot was planted in 2010 with the industry standard variety, “Montmorency” in high-density spacing on dwarf rootstocks.  A second plot was established in the summer of 2011 for future testing using different genetic dwarf and compact material.

“The impact of this project -- if the technologies and economics prove efficient and profitable -- will be long-term and will be measured by the number of continuous-harvest machines adopted by the industry, and the number of acres that adopt improved tart cherry genotypes and other tree-related innovations,” Perry said.

Other AgBioResearch scientists working on the project are Dan Guyer, a professor in the MSU Department of Biosystems and Agricultural Engineering; and Greg Lang, Amy Iezzoni and Jim Flore, all professors in the MSU Department of Horticulture. In addition, MSU Extension coordinators Nikki Rothwell, with the Northwest Michigan Horticulture Research Center, and Philip Schwallier with the Clarksville Research Center are part of this research group. Susanne Thornsbury, formerly with the MSU Department of Agricultural, Food and Resource Economics, also worked on the project.

In addition to support from AgBioResearch, this project received funding from Project GREEEN (Generating Research and Extension to meet Economic and Environmental Needs), the state’s plant agriculture initiative at MSU, and the Michigan cherry industry.