Farm mechanization, technology soon may replace labor-intensive farming

Produce growers who are running short of workers are turning to computer-guided robots for tasks such as thinning lettuce fields. The See and Spray thinner, manufactured by Blue River Technology, directs microjets of water to kill seedlings and make room for heads to grow fuller.  (Gary Coronado / Los Angeles Times)

A lettuce field near Salinas, Calif., shows the work done recently by a computer-guided machine that thinned unwanted sprouts to leave room for lettuce to grow larger. The Auto Thinner, manufactured by Mantis Ag Technology, based in the Salinas Valley, can replace 20 farm workers who usually hoe the field by hand.  (Gary Coronado / Los Angeles Times)

Rows of lettuce sprouts in a field near Salinas, Calif., await thinning by a computer-guided robotic device on May 23, 2017. The machine, which eliminates unwanted lettuce plants, replaces about 20 farm laborers.  (Gary Coronado / Los Angeles Times)

Agricultural worker Alicia Solano, 17, of Oaxaca, Mexico, thins rows of lettuce near Salinas, Calif., on March 14, 2017. A computer-guided machine had done the bulk of the work, leaving her small crew to hoe only what it missed.  (Gary Coronado / Los Angeles Times)

The PlantTape automated transplanting system places romaine lettuce pods into the soil for the Tanimura & Antle produce company in Salinas, Calif., on March 13, 2017. The tape will decompose in the soil.  (Gary Coronado / Los Angeles Times)

A worker examines a strand of PlantTape, part of an automated transplanting system for romaine lettuce pods. Operated with as few as two workers, the machine replaces decades-old technology that required a crew of about 10.  (Gary Coronado / Los Angeles Times)

Farmworker Miguel Sanchez demonstrates a PlantTape automated transplanting system placing romaine lettuce into the soil near Salinas, Calif., on March 13, 2017.  (Gary Coronado / Los Angeles Times)

SALINAS, CALIF. -- MONDAY, MARCH 13, 2017: A demonstration of Plant Tape automated transplanting system placing romaine lettuce pods into the soil for Tanimura & Antle produce growers in Salinas, Calif., on March 13, 2017. The growing medium is sandwiched between two layers of biodegradable tissue. (Gary Coronado / Los Angeles Times)  (Gary Coronado / Los Angeles Times)