Mexican Police Bust 300-Acre Pot Plantation

Marijuana plants lay in a pile before being burned by the army in the Sierra de Juarez in Ensenada, Mexico, Thursday Sept. 30, 2010. According to Army Gen. Alfonso Duarte Mujica, soldiers have destroyed 73 hectares of marijuana in the northern region of Mexico's Baja California peninsula in 2010. (AP Photo/Guillermo Arias) (AP)

Authorities busted a 300-acre marijuana plantation in Mexico – the largest one ever discovered in the country, the Defense Department said.

The plantation is four times larger than the second biggest marijuana fields ever found by authorities, discovered 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 kms) south of the U.S. border.

Video of the plantation showed a sophisticated system of piped-in irrigation to support the plants, some of which were several feet tall.

The plantation also included some wooden outbuildings, presumably for use by people caring for the plants.

The Defense Department said soldiers made the latest discovery during a patrol Tuesday but didn't specify exactly where the fields were found. The department said it would take journalists to view the find.

Troops usually destroy such fields by cutting down the plants and burning them.

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

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 around 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 were the work of the Sinaloa cartel, headed by Mexico's most-wanted drug lord, Joaquin "El Chapo" Guzman.

It was unclear which cartel, if any, operated the plantation found Tuesday.

Based on reporting by The Associated Press.