Sensing good fruit
Michigan State University researchers work to develop sensors that could assess fruit quality.
Dr. Renfu Lu is using multispectral-based prototype sorting equipment to determine internal apple quality.
There's new interest in technology for specialty crops, thanks in part to the Technology Roadmap for Tree Fruit Production. The roadmap started dialogue in the Pacific Northwest six years ago and helped spread the goal to reduce inputs across the nation beyond tree fruit, says a Michigan State University agricultural engineer. As a result of the heightened interest, funding for technology research for specialty crops is contained in the federal Farm Bill being debated at Good Fruit Grower press time.
Daniel Guyer of MSU's Biosystems and Agricultural Engineering Department, shared a few of the latest research concepts and projects with growers attending the Great Lakes Fruit, Vegetable, and Farm Market Expo. The annual trade show was held in December in Grand Rapids, Michigan.
As he highlighted various projects that aim to reduce production costs, Guyer noted that although labor has been at the forefront of concerns, the technology roadmap is broader than only labor. Crosscutting concerns that were discussed at a workshop last spring with the industry, the U.S. Department of Agriculture, the National Aeronautical Space Administration, the National Science Foundation, and others, involved the topics of product quality, labor cost and availability, and the environmental footprint. "Those were the three things that cut across all crops and all regions," he said.
Guyer said that the areas being targeted for research and development include: sensors for product characterization; more effective and --efficient use of water, nutrients, and chemicals; automated systems to reduce labor costs; and better economic models and support for --decision-making.
While the robotic-style harvesting technology has gotten much press and media attention lately, a completely automated system involves more than just a robotic harvester. The role of thinning and pruning by an automatic system is being looked at, as well as electronic sensing to evaluate internal and external fruit quality as it is picked. Other components of an automated orchard system that are under development are sensors on sprayers, automated scouting for crop estimation, biosensors to --indicate water or nutrient stress, contamination sensors, and agricultural weather-based insect and disease models.
At MSU, engineers are testing a new concept in canopy shaking to get tart cherry trees into production faster and possibly reduce fruit damage. Young tart cherry trees can be damaged from the shaking from existing mechanical harvesters. "Instead of expecting the fruit to come down to the catching frame, how about taking the catching frame up to the fruit?" Guyer asked.
They have been using a small shaker unit developed at the U.S. Department of Agriculture in West Virginia for bramble harvest. Similar USDA shaker harvest technology is being tested for use in stem-free, fresh cherries. A larger unit is available commercially for citrus harvest.
MSU is also working on a one-man harvesting aid that would improve labor efficiency.
Guyer and Dr. Renfu Lu, USDA engineer stationed at MSU, are developing sensors that could be used in a variety of settings, both within the orchard and as part of automated orchard systems.
Within MSU laboratories, scientists are investigating the use of electronic insect detection in cherries, looking inside the fruit. "Can we use wavelengths that we can't see with our eyes to see defects earlier in the process and development of the disease or whatever?" he wondered. Researchers are also looking at biosensors that would indicate tree nutrient stress or moisture stress.
The USDA laboratory at MSU is focusing on assessing fruit quality traits through the use of sensors, Lu said. Commodities that have been studied include apples, cherries, pears, peaches, and cucurbits.
Lu is developing a novel light-scattering, nondestructive technique that uses near-infrared wavelengths to detect fruit sweetness and firmness. Digital imaging is used in many packing houses to sort fruit by size and for external defects, but the technology is only skin deep and can't detect internal maladies like bruising or browning at the core.
Two years ago, Lu and his research team developed a portable firmness tester that can work in conjunction with a computer or as a stand-alone device. They are also working on a method to measure the gloss and color of apples.
One of their more comprehensive research projects is the development of sensors that could be used to measure the apple maturity attributes in an orchard. Lu said that sensors and imaging techniques that give growers information about color, acidity, sugar, starch, and firmness would help them measure quality of fruit in the field, "and even on the tree."
Growers could use the fruit quality data to presort in the field, change instructions for picking crews, and provide the packing house with additional data to use in optimizing the storage and marketing of fruit.