Ranong Rachasing would normally be in her fields at this time of year, toiling in ankle-deep water to make her rice paddies bloom through knowledge honed by years of cultivating Thailand's most celebrated export.

Now the wizened 57-year-old's fields lie fallow, baking under a blazing summer sun while Ranong gazes skywards for clouds that never seem to appear.

"This year is worse than any other. There has been no rain, so there is no water. It is the most severe drought I've ever seen," she told AFP while standing in a cracked field in Bang Pla Ma district, Suphanburi province, a two-hour drive north of Bangkok.

Thailand's vital rice belt is being battered by one of the worst droughts in living memory, forcing impoverished farmers deeper into debt and heaping fresh pain on an already weak economy -- seen as the junta's Achilles heel.

When they seized power in May 2014, Thailand's generals promised to restore order and prosperity after months of street protests paralysed the elected government of Yingluck Shinawatra and brought the economy to a near standstill.

By severely curtailing civil liberties, former army chief turned Prime Minister Prayut Chan-O-Cha has largely managed to renew calm.

But the generals have proven less adept at kickstarting what was once one of Southeast Asia's most vibrant economies.

- Lacklustre growth -

Post-coup gains of a rebound in tourism and increased fiscal spending have been offset by disappointing exports, declining manufacturing and weak local demand.

In May the country's economic planning agency further revised down its GDP growth forecast for the year to between 3.0-4.0 percent, one of the lowest rates in Asia and well below Prayut's hopes for at least 4.5 percent.

Now the kingdom faces the prospect of a dismal main harvest of rice -- traditionally one of the country's top exports.

Water levels in some of the main reservoirs are at their lowest levels in 20 years prompting the junta to call on farmers in the Chao Praya river basin to delay sowing crops.

Prayut also ordered officials to clear irrigation channels, dig more ground wells and employ cloud seeding technology to create artificial rainfall.

But the wet season has yet to arrive in earnest and water remains precariously elusive for many.

To the untrained eye Thailand's drought is deceptive. Across much of Suphanburi province many fields appear green and crop-filled.

"The colour is wrong, too yellow" explains Samien Hongto, the spry 72-year-old chairman of the Central Farmers Network as he surveys rice fields close to his village.

"If we don't get rain in the next few days, these crops will die."

Down the road a field has done just that and a herd of buffaloes has been allowed in to graze on what remains. Away from the main irrigation channels the planted fields become a rarity.

Vichai Priprasert, president of the Thai Rice Exporters Association, estimates just 30-40 percent of the fields have been planted, with no guarantee those will make it to harvest.

"I've never seen it this bad. And I've been working in this industry for 40 years or so," he told AFP.

- Junta 'vulnerable' -

A poor rice harvest is more than just an economic headache for the junta -- it is a political dilemma.

Last year's coup was the latest episode in Thailand's long running political conflict that broadly pits a pro-military Bangkok-based middle class and royalist elite against poorer voters loyal to Yingluck and her also ousted former premier brother Thaksin.

Puangthong Pawakapan, a Thai politics expert at Chulalongkorn University, says many of the country's "anti-Shinawatra" middle classes were happy to support draconian rule in return for economic prosperity.

"But now it is quite clear that the junta is so incompetent in handling the country's economic problems," she said.

Most of Thailand's rice farmers hail from the country's populous north, where love for the ousted Shinawatras remains strong partially because they heavily subsidised the rice industry.

But analysts say failed crop harvests will also erode crucial support among some of the military's natural allies because it looks set to further dent already disappointing economic growth.

"The dictatorship is extremely vulnerable to the economy downturns because such issues could lose the junta support from Bangkok-centred middle and upper classes, the only groups in Thailand supporting the junta," Paul Chambers, director of research at the Institute of South East Asian Affairs in the northern city of Chiang Mai told AFP.

For Somjit Paengpan, a 48-year-old farmer yet to lay down any seeds, the rough and tumble of the capital's politics is the least of her concerns.

She took a loan out last year to pay for a tractor that now lies unused.

"Without rice I won't have any income," she lamented. "What am I to do?"