Posts Tagged: tomatoes

Taking the drudgery out of weed control

For automated, mechanical weed control to work, scientists must teach machines how to distinguish between unwanted vegetation and the crop being cultivated. A new, high-tech system using x-rays to detect tomato stems is under development by UC Davis Cooperative Extension agricultural engineer David Slaughter and USDA Agricultural Research Service researcher Ron Haff. The output from the x-ray detector is input to a microcontroller that controls a pair of pneumatically powered mechanical weed knife blades.

Slaughter and Haff's work was explained this week in an online newsletter produced by Vision Systems Design, an organization that provides automation solutions for engineers and integrators worldwide.

The mechanical weeding machine includes an x-ray mounted to the side of a shielded tunnel that is pulled behind a tractor over the row of tomato plants. As the x-rays radiate across the tunnel, they are detected by an array of 32 photodiodes whose output is tied to a single point at the input of a summing amplifier, the story says.

The system was used in field trials on a 15-meter row containing 39 standing tomato seedlings. At a speed of about 1 mile per hour, the detection system identified all 39 stems of standing plants with no false positives.

Tomato field infested with field bindweed.

Food prices are rising to meet consumer demand

A New York Times opinion piece invited four prominent economists to explain why they believe food prices are rising. The paper had reported that food prices spiked in April, even as oil and gas prices were down.

One of the experts, UC Davis Cooperative Extension agricultural economist Roberta Cook, made the point that food prices are rising because consumers have signaled they are willing to pay more to get what they want.

For example, consider the tomato. "A tomato is no longer a tomato is no longer a tomato," Cook wrote. "American consumers complained for years that tomatoes no longer tasted like tomatoes. The market responded to give them more of what they want."

Getting what they want increased prices.

Cook wrote that specialty tomatoes cost more to produce and harvest; they have a shorter shelf life, so there's more spoilage. Traditional round, mature-green tomatoes are giving way to specialty tomatoes, such as Campari, on-the-vine, strawberry, romas-on-the-vine, and many others. Field grown fresh tomatoes now include grape tomatoes, mini-pear tomatoes of various colors, and extended shelf-life vine-ripe round tomatoes.

In general, she wrote, quality across all tomato types has improved. The better products are commanding higher prices.

tomatoes

UC studies the use of compost to restore burned areas

Scientists at UC Riverside will apply compost to wildfire-ravaged land after the flames have been doused to determine whether it helps reduce erosion and water pollution and restore vegetation. The project is one of several to be undertaken with funding from the California Integrated Waste Management Board aimed at finding uses for what is expected to be an abundance of compost made from organic waste diverted from landfills, according to a story in the April issue of BioCycle.

The Waste Management Board plans to cut the amount of organic materials now going to landfills by half in the next 10 years. Meeting that goal will require an additional 15 million tons of organic materials to be recycled annually.

The Riverside scientists will quantify the benefits of compost on fire-damaged land by absorbing water, thus reducing surface flow, and by dissipating the energy of rainfall. The study will also attempt to quantify the ability of compost to promote the growth of micro and mesofauna (microbes, worms, insect larvae) in the fire-damaged soil, the BioCycle story says.

Another UC Riverside study funded by the Waste Management Board is focused on using the compost in strawberry, lettuce and tomato production.

Developing crop-specific compost specifications helps farmers avoid using mismatched or poor quality composts, which could result in lower crop yields, according to the article.

UC expert wonders out loud about lycopene in tomatoes

Continuing the tomato trend from my last blog post, the loss of nutrients in tomatoes from the canning process was pondered in another San Francisco Chronicle article.

For this one, freelancer Deborah Rich spoke to Diane Barrett of the UC Davis Center for Fruit and Vegetable Quality.

There is controversy, Rich wrote, about the fate of fat-soluble nutrients like the antioxidant lycopene in tomato processing. Studies suggest that processing increases the levels of lycopene relative to the naturally occurring levels in fresh tomatoes, the Chron story says.

Barrett told the reporter she isn't convinced that processing can cause tomatoes to synthesize greater amounts of lycopene. Instead, she says that processing may make lycopene easier to measure.

"Are we, with heat, just loosening the matrix of the plant and allowing us in the laboratory to analyze a higher content of that particular nutrient?" Barrett was quoted. "My scientist hat makes me wonder."

Perhaps the change is due to an alteration in lycopene's molecular structure, as suggested by the Ohio State study I referred to in the earlier blog post.

Mid-summer tomato news

Who could resist tomatoes in mid-summer? Roadside stands around town (at least in Fresno) offer the beautiful, healthful, locally grown fruit for the best prices you'll see all year.

Apparently, media are also seeing red. The San Francisco Chronicle ran a lengthy piece over the weekend about processing tomatoes, fruit carefully bred for high soluble solids and portability that is transformed into spaghetti and pizza sauces, tomato paste, soup and other products. Of the 12.7 million tons of processing tomatoes grown in the United States, 95 percent come from California, the story says.

Drilling down further, the article reports that just 225 growers in the Central Valley produce California's entire crop on 277,000 acres. Most grow their crop under contract for one of California's 16 commercial tomato canneries.

For the story, freelance writer Deborah Rich spoke to the director of UC Cooperative Extension in Colusa County, Mike Murray. He said that, in his county, only eight farmers grow a total of 25,000 acres of tomatoes; before 1979 the county had at least 50 processing-tomato growers.

"The industry has evolved that way," Murray is quoted in the story. "The only way that these guys are making any money on tomatoes is by volume. Processed tomatoes are basically a commodity."

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Fresh tomato safety made a big splash in the media this summer when it was first alleged that the verastile fruit was responsible for a string of salmonella poisonings around the nation. Even People Magazine included an article. In its July 21 issue, UC Davis food safety specialist James Gorny commented on the challenges associated with finding a culprit for some food poisoning outbreaks.

"Tomatoes from different farms are often mixed together and follow a complex distribution chain before they hit grocery store shelves or arrive at a restaurant," the magazine said. Then it quoted Gorny: "It becomes very difficult to find your smoking gun."

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ANR wasn't involved in this last story, but since we're talking about tomatoes . . . US News & World Report ran an article about research done by our colleagues at Ohio State that confirmed high-heat processing of tomatoes changes the molecular structure of lycopene, making it easier for the healthful antioxidant to be absorbed into the blood stream. A naturally occurring red pigment, lycopene is believed to help prevent cancer and other chronic diseases.

Tomatoes contain healthful nutrients.

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