The all new
CBS News App for Android® for iPad® for iPhone®
Fully redesigned. Featuring CBSN, 24/7 live news. Get the App

Army finds biggest pot plantation ever in Mexico

MEXICO CITY - Mexican soldiers have found the largest marijuana plantation ever detected in Mexico, a collection of marijuana fields covering almost 300 acres, the Defense Department said Thursday.

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