TODOS SANTOS, Mexico - Containers on supermarket shelves in the United States may depict verdant fields, tangles of vines and ruby red tomatoes. But at this time of year, the tomatoes, peppers and basil certified as organic by the Agriculture Department often hail from the Mexican desert, and are nurtured with intensive irrigation.

Growers here on the Baja Peninsula, the epicenter of Mexico's thriving new organic export sector, describe their toil amid the cactuses as "planting the beach."

Del Cabo Cooperative, a supplier here for American supermarkets, is sending more than six and a half metric tons of organic tomatoes and basil every day to the United States by truck and plane to sate the American demand for organic produce year-round.

But even as more Americans buy foods with the organic label, the products are increasingly removed from the traditional organic ideal: produce that is not only free of chemicals and pesticides but also grown locally on small farms in a way that protects the environment.

The explosive growth in the commercial cultivation of organic tomatoes here, for example, is putting stress on the water table. In some areas, wells have run dry, meaning that small subsistence farmers cannot grow crops. And the organic tomatoes end up in an energy-intensive global distribution chain that takes them as far as New York and Dubai, United Arab Emirates, producing significant emissions that contribute to global warming.

From now until spring, farms from Mexico to Chile to Argentina that grow organic food for the United States market are enjoying their busiest season.

"People are now buying from a global commodity market, and they have to be skeptical even when the label says 'organic' - that doesn't tell people all they need to know," said Frederick L. Kirschenmann, a distinguished fellow at the Leopold Center for Sustainable Agriculture at Iowa State University. He said some large farms that have qualified as organic employed environmentally damaging practices, like planting only one crop, which is bad for soil health.

Many growers and environmental groups in Mexico defend the export-driven organic farming, even as they acknowledge that more than a third of the aquifers in southern Baja are categorized as overexploited by the Mexican water authority. With sophisticated irrigation systems and shade houses, they say, farmers are becoming more skilled at conserving water. They are focusing farms in "microclimates" near underexploited aquifers, such as in the shadow of a mountain.

They also point out that the organic business has transformed what was once a poor area of subsistence farms and where even the low-paying jobs in the tourist hotels and restaurants in nearby Cabo San Lucas have become scarcer during the recession.

To carry the Agriculture Department's organic label, farms in the United States and abroad must comply with a long list of standards that prohibit the use of synthetic fertilizers, hormones and pesticides, for example. But the checklist makes few specific demands for what would broadly be called environmental sustainability, even though the 1990 law that created the standards was intended to promote ecological balance and biodiversity as well as soil and water health.

Experts agree that organic farms tend to be less damaging to the environment than conventional farms. In the past, however, "organic agriculture used to be sustainable agriculture, but now that is not always the case," said Michael Bomford, a scientist at Kentucky State University who specializes in sustainable agriculture. He added that intense organic agriculture had also put stress on aquifers in California.

Some organic standard setters are beginning to refine their criteria so that organic products better match their natural ideals. Krav, a major Swedish organic certification program, allows produce grown in greenhouses to carry its "organic" label only if the buildings use at least 80 percent renewable fuel, for example. And last year the United States Agriculture Department's National Organic Standards Board revised its rules to require that for an "organic milk" label, cows had to be at least partly fed by grazing in open pastures rather than standing full time in feedlots.

But each decision to narrow the definition of "organic" involves an inevitable tug-ofwar among farmers, food producers, supermarkets and environmentalists. While the United States' regulations for organic certification require that growers use practices that protect water resources, it is hard to define a specific sustainable level of water use for a single farm "because aquifer depletion is the result of many farmers' overutilizing the resource," said Miles McEvoy, head of the National Organic Program at the Agriculture Department.

While the original organic ideal was to eat only local, seasonal produce, shoppers who buy their organics at supermarkets expect to find tomatoes in December and are very sensitive to price. Both factors stoke the demand for imports.

At a five-year-old organic farm, Rosario Castillo says he can cultivate only eight of 40 hectares he has earmarked for organic production, although he dug a well seven months ago to gain better access to the aquifer. The authorities ration pumping and have not granted him permission to clear native cactuses. "We have very little water here, and you have to go through a lot of bureaucracy to get it," Mr. Castillo said.

Many Mexican growers blame tourist development - hotels and golf courses - for the water scarcity. But farming can also be a significant drain. According to one study in an area of northern Baja called Ojos Negros, a boom in the planting of green onions a decade ago lowered the water table by about 40 centimeters a year.

"They were pumping a lot of groundwater," said Victor Miguel Ponce, a professor of hydrology at San Diego State University, "and that was making some people rich on both sides of the border at the expense of the environment."

David Agren contributed reporting.

The New York Times

(China Daily 01/08/2012 page10)