The Lettuce Bot, a high-tech farmhand

Gosia Wozniacka and Terence Chea / The Associated Press /

Published Jul 17, 2013 at 05:00AM

SALINAS, Calif. — On a windy morning in California's Salinas Valley, a tractor pulled a wheeled, refrigerator-sized contraption over rows of budding iceberg lettuce plants. Engineers from Silicon Valley tinkered with the software on a laptop to ensure the machine was eliminating the right leafy buds.

Hired by a Salinas-based agricultural produce company, the engineers were testing the Lettuce Bot, a machine that can “thin” a field of lettuce in the time it takes about 20 workers to do the job by hand.

The thinner is part of a new generation of machines that target the last frontier of agricultural mechanization — fruits and vegetables destined for the fresh market, not processing, which have thus far resisted mechanization because they're sensitive to bruising.

Researchers are now designing robots for these most delicate crops by integrating advanced sensors, powerful computing, electronics, computer vision, robotic hardware and algorithms, as well as networking and high precision GPS localization technologies. Most ag robots won't be commercially available for at least a few years.

In this region known as America's Salad Bowl, where for a century fruits and vegetables have been planted, thinned and harvested by an army of migrant workers, the machines could prove revolutionary.

Though they cost millions of dollars, farmers say, the robots are worth the investment: They could provide relief from recent labor shortages, lessen the unknowns of immigration reform, even reduce costs, increase quality and yield a more consistent product.

“There aren't enough workers to take the available jobs, so the robots can come and alleviate some of that problem,” said Ron Yokota, a farming operations manager at Tanimura & Antle, the fresh produce company that hired the Lettuce Bot.

Many sectors in U.S. agriculture have relied on machines for decades and even the harvesting of fruits and vegetables meant for processing has slowly been mechanized. But nationwide, the vast majority of fresh-market fruit is still harvested by hand.

Research into fresh produce mechanization was dormant for years because of an over-abundance of workers and pressures from farmworker labor unions.

In recent years, as the labor supply has tightened and competition from abroad has increased, growers have sought out machines to reduce labor costs and supplement the nation's unstable agricultural workforce. The federal government, venture capital companies and commodity boards have stepped up with funding.

“We need to increase our efficiency, but nobody wants to work in the fields,” said Stavros Vougioukas, professor of biological and agricultural engineering at the University of California, Davis.

But farmworker advocates say mechanization would lead to workers losing jobs, growers using more pesticides and the food supply becoming less safe.

“The fundamental question for consumers is who and, now, what do you want picking your food; a machine or a human, who with the proper training and support, can” ... take significant steps to ensure a safer, higher quality product, said Erik Nicholson, national vice president of the United Farm Workers of America.

On the Salinas Valley farm, entrepreneurs with Mountain View-based startup Blue River Technology are trying to show that the Lettuce Bot would not only replace two dozen workers, but also improve production.

“Using Lettuce Bot can produce more lettuce plants than doing it any other way,” said Jorge Heraud, the company's co-founder and CEO.

After a lettuce field is planted, growers typically hire a crew of farmworkers who use hoes to remove excess plants to give space for others to grow into full lettuce heads. The Lettuce Bot uses video cameras and visual-recognition software to identify which lettuce plants to eliminate with a squirt of concentrated fertilizer that kills the unwanted buds while enriching the soil.

The company, which raised $3 million from a major Silicon Valley venture capital firm for the Lettuce Bot, also plans to develop machines to automate weeding — and eventually harvesting — using many of the same technologies.

Another company, San Diego-based Vision Robotics, is developing a similar lettuce thinner as well as a pruner for wine grapes. The pruner uses robotic arms and cameras to photograph and create a computerized model of the vines, figure out the canes' orientation and the location of buds — all to decide which canes to cut down.

A new generation of machines aims to mechanize the last frontier of farming: produce picked for the fresh market. Meanwhile, farmworker advocates watch with apprehension.

Meanwhile, about the earliest farmers

— A rich trove of artifacts and plant remains excavated from southwestern Iran suggests that ancient humans' transition from hunting and gathering to farming occurred throughout the Fertile Crescent at roughly the same time.

The excavation also revealed that this crucial change — which helped the region earn its reputation as the cradle of civilization — happened gradually over thousands of years, not in a few generations or centuries as previously thought, according to a study published this month in the journal Science.

The findings from the excavation in the foothills of the Zagros Mountains represent a paradigm shift in scholars' understanding of agriculture's origins, and the villages, towns and civilizations that emerged as a result, experts said.

For decades, archaeologists believed agriculture took root in a part of the Fertile Crescent called the Levant, which includes present-day Israel, Lebanon and Jordan as well as parts of Syria, Iraq, Saudi Arabia and other countries. From there, it was thought to have spread eastward to present-day Iran.

“The eastern Fertile Crescent has been treated as backwater,” said Melinda Zeder, a senior scientist at the Smithsonian Institution's Program in Human Ecology and Archaeobiology, who was not involved in the study. Now, the understanding that people in the Zagros grew and ground cereal grains as early as their counterparts in the Levant has “democratized this situation where everyone in the region was involved,” she said.

The items unearthed by archaeologists from the University of Tuebingen in Germany from the 7-acre site were remarkably well preserved. Perched at the edge of a former looter's pit, the archaeologists drew up 10-liter buckets filled with botanic and stone remains. They rinsed off the sediment and discovered human and animal figurines, fish bones and charred bits of wild barley, lentil, grass peas, emmer wheat and other ancestors of crop plants.

“I've never seen a site so rich,” said Nicholas Conard, an archaeologist at the University of Tuebingen and co-author of the study.

— Los Angeles Times

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