"I knew about the warning, but I just didn't realise it would become this bad," she said, looking sadly at her withering rice.

"This is the worst drought in my whole life," Luen, 54, told Reuters in her rice field in Phimai district, about 400 km (250 miles) northeast of Bangkok.

The whole of her water-dependent crop would die unless there was rain within 15 days, Luen said. That would cost her the 3,000 baht ($78) it took to plant it and the 10,000 baht ($260) she would get from selling a normal crop.

"I am praying for rain. I used to pray to ask for something else, but not for rain. This is the first time," said Luen, whose family still owes more than 200,000 baht it has ploughed into the farm over the years.

"I'd feel so horrible if I end up having to buy rice to eat," said Luen, who started growing rice when she was seven.

The drought is affecting 9.6 million farmers in a country where more than 60 percent of the population depends on agriculture.

It has spread to 66 of Thailand's 76 provinces and forced local authorities to stop supplying water for irrigation, on which much dry-season farming depends.

The Agriculture Ministry puts losses in damaged crops and lost exports at 23.72 billion baht. It says Thailand, the world's biggest rice exporter, will ship only 8.5 million tonnes of it overseas this year, 15 percent less than in 2004.

VILLAGERS HEAD TO CITY

"My sister has left for Bangkok to find a job. Without water, we could do nothing," said Kham Karnphannin, a 46-year-old rice farmer in nearby Samrit village.

Kham said he had lost about 1,000 baht ($26) a month in sales of vegetables he normally grows in the dry season.

"Our main river, Moon river, has turned salty due to drought. We can't use it for irrigation and we can't even drink it," said Kham, standing by a river he can now walk across.

More than 20,000 villagers have moved to Bangkok in hopes of finding work since November, Labour Ministry figures show.

The drought is expected to shave 0.37 of a percent, or about 27 billion baht, off Thailand's Gross Domestic Product (GDP), the KGI brokerage said.

"Drought is a concern as it can create an indirect impact by significantly affecting 60 percent of the Thai population who are still in the agricultural sector," it said in a report.

The government has said it was preparing cloud-seeding operations in 22 provinces this week with 17 planes, but was not optimistic because the air was too dry.

If there was no rain in May, when the wet season should start, things could go from bad to worse, analysts and officials said.

"By that time, water supplies would run short, even for consumption and industrial production," the Phatra Securities brokerage said in a report.

But, with water levels shrinking in many dams and reservoirs across vast areas, there is a silver lining for some.