* Mexican cartels generate bulk of revenue from marijuana
* Marijuana seizures in California soar 300 pct in 4 years
* Mexican growers forced to compete with higher quality
By Mica Rosenberg
AMATA, Mexico, Dec 14 (Reuters) - Farmers growing marijuana in remote Mexican mountains are adopting techniques pioneered in the United States to produce more potent pot and boost profits from the cash crop that is fueling a deadly drug war.
In the fertile mountain valleys of Sinaloa in northwestern Mexico, soldiers this year found 60 acres (24 hectares) of covered greenhouses equipped with sophisticated irrigation and fertilization systems growing seemingly endless rows of marijuana plants.
In another part of Sinaloa, the cradle of Mexican drug trafficking, the army recently busted a marijuana lab that used lamps day and night to speed the growth of the plants, a change from traditional outdoor cultivation of the crop and a sign drug cartels are using more savvy production methods.
"This is new. They now have technology so the plant will grow faster; we think the techniques are coming from (the United States)," said an officer commanding a battalion ripping up 5-foot (1.5-meter) high marijuana plants growing along a river bank near the dusty town of Amata, Sinaloa.
While estimates vary, law enforcement officials on both sides of the border say Mexican drug gangs earn the bulk of their cash from cheap-to-produce marijuana, using revenues to sustain wars against rivals and the government that have killed more than 33,000 people across Mexico in the past four years.
Full coverage of drug war http://link.reuters.com/wam89p
Factbox on political risks in Mexico [ID:nRISKMX]
Even as hundreds of troops fan out across Sinaloa ripping up marijuana fields by hand, cartels are one step ahead of the government's efforts, helping to stifle President Felipe Calderon's army-led battle against the drug traffickers.
"It's a cycle," said another soldier in Amata as he stood by 20,000 pungent marijuana plants doused with diesel and set on fire in a billowing cloud of white smoke. "We come and destroy the fields and move onto another area and they come back and start preparing the land to plant again."
The new greenhouses are harder for the army to detect with fly-overs since they resemble tomato plots common in Sinaloa.
"PRIMO BUD VS MEXICAN CRUD"
If drug gangs in Mexico are successful enhancing the quality of their product, they can sell the improved marijuana for up to five times the normal price. The going rate for top quality U.S. marijuana is around $2,500 per pound, while Mexican types sell for under $500, U.S. law enforcement officials say.
New cultivation tactics are a sign Mexico is being forced to compete with growers north of the border, especially in California where business is booming, spurred on by marijuana for medical use in 15 states and the District of Colombia.
"I've been in drug law enforcement since 1970 and I never in my wildest dreams thought I would say California is producing more marijuana than Mexico," said Bill Ruzzamenti, a police officer specializing in the marijuana trade in California's Central Valley. "But there are people willing to spend the money on what they perceive to be primo bud as opposed to the Mexican crud," he added.
Seizures of marijuana plants in California soared nearly 300 percent over the past four years. Output increased south of the border as well between 2006 and 2008, but not by so much.
Clandestine marijuana fields are cropping up with more frequency in the United States, even in national parks.
Ruzzamenti speculated that Mexican growers in the United States are taking knowledge learned from experienced marijuana botanists cultivating strong new strains with names like "train wreck" and "California dream" back home to Mexico.
Indoor operations are increasing in the United States, in part because THC content, the drug's active ingredient, shoots up when marijuana is tended in greenhouses. THC in marijuana seized in the United States increased nearly 250 percent in the past two decades, according to the U.S. State Department.
Some U.S. varieties reach upwards of 30 percent THC, while Mexican pot averages between 3 and 4 percent, said Tommy Lanier, who directs the National Marijuana Initiative, funded by the White House Office of National Drug Control Policy.
Lanier questions the medical value of such strong marijuana and said legitimate crops can be diverted to the black market.
"They say its used for pain management, but drinking a bottle of Jack Daniels would have the same effect," he said. (Editing by Robin Emmott)
Our Standards: The Thomson Reuters Trust Principles.