Army finds Mexico's biggest marijuana plantation

TIJUANA, Mexico (AP) — Mexican soldiers have found the largest marijuana plantation ever detected in Mexico, a huge field covering almost 300 acres (120 hectares), the Defense Department said Thursday.

The plantation is four times larger than the previous record discovery by authorities at a ranch in northern Chihuahua state in 1984.

The pot plants sheltered under black screen-cloth in a huge square on the floor of the Baja California desert, more than 150 miles (250 kilometers) south of Tijuana, across the border from San Diego.

Army Gen. Alfonso Duarte said the screening, which is often used by regular farmers to protect crops from too much sun or heat, made it difficult to detect from the air what was growing underneath.

It was only when soldiers on the ground reached the isolated area Tuesday that they found thousands of pot plants as high as 2.5 yards (meters) tall. The average height of the plants was about 1.5 yards (meters). Duarte said they were not yet ready for harvest.

"We estimate that in this area, approximately 60 people were working. When they saw the military personnel, they fled," Duarte told reporters. A few were later reportedly detained at a nearby roadblock, but Duarte said no arrests were made at the scene.

He said traffickers could have harvested about 120 tons of marijuana from the plantation, worth about 1.8 billion pesos (about $160 million).

Video of the plantation showed a sophisticated system of piped-in irrigation to support the plants, which Duarte said was fed by two wells. The plantation also included some wooden outbuildings, presumably for use by people caring for the plants.

Troops will destroy the fields by burning them, Duarte said.

The site is the near the coastal town of San Quintin. Journalists were en route there Thursday under army escort.

While it's unknown how much of Mexican drug cartels' income comes from marijuana, recent discoveries suggest it remains a large-scale trade.

Last October, Mexican authorities made their largest-ever seizure of marijuana packaged for sale, a record 148 tons (134 metric tons) found in a number of tractor trailers and houses in Tijuana. They appeared to make up a major distribution center traced directly to Joaquin "El Chapo" Guzman, Mexico's most-wanted fugitive, who has expanded the reach of his Sinaloa cartel along the U.S.-Mexico border since escaping from prison in 2001.

In November, U.S. and Mexican investigators found two long, sophisticated tunnels under the border between Baja California and California, along with more than 40 tons of marijuana in and around the tunnels.

The tunnels ran about 2,000 feet from Mexico to San Diego and were equipped with lighting, ventilation and a rail system for drugs to be carried on a small cart.

U.S. officials say they believe the tunnels also were the work of the Sinaloa cartel.

While the Arellano Felix or Tijuana cartel long dominated the drug trade in Baja California, the cartel has been greatly weakened by government hits on its leadership, and authorities say there are signs that the Sinaloa cartel now also operates in the area.

Duarte said he did not know which group operated the plantation found Tuesday