A prolonged drought in Taiwan now threatens not only the island's farmers, but its hi-tech industry as well.

Making semiconductors - one of Taiwan's most important growth industries - requires a lot of water, to wash the chips after etching.

Companies in Silicon Valley which depend on... UMC for production would be crippled

HSBC analyst

With water in short supply, the authorities are now exploring every method to make it rain.

The airforce in Taiwan has been ordered to sprinkle clouds with chemicals that can trigger a downpour.

Some local officials have opted for less conventional approaches, including animal sacrifices.

Making it rain

"The government is preparing to make rain with assistance from the airforce" to prevent factory shut-downs, Prime Minister Yu Shyi-kun has promised.

The planes are scheduled to take off on Thursday - as long as there is enough cloud.

"If it doesn't rain, we will ask the government to co-ordinate the water resources of the entire island", said John Hsuan, vice-chairman of United Microelectronics Corp (UMC).

UMC is one of the world's biggest foundry chip makers, turning out components for US firms such as Intel and Microsoft.

Firms in Hsinchu County's science park, the island's main hi-tech zone, had sales worth $18.9bn last year.

Water trucks run dry

Earlier this month, farmers were ordered to take 14,000 hectares of rice paddies out of production to conserve water for hi-tech firms.

The crop ban - in force since 1 March - may be extended to another 26,000 hectares, Mr Yu said at the weekend.

Some hi-tech firms in Hsinchu science park have warned they may not be able to continue trucking in water to keep production going for much longer.

"There aren't enough trucks to bring in all the water that companies in Hsinchu need and it's very expensive", an executive at AU Optronics told the Taipei Times.

AU Optronics is Taiwan's biggest maker of flat liquid crystal display screens for laptop computers.

"If there isn't any rain in the next month, some of the companies may need to cut their capacity", agreed Lloyd Tsai, an investment fund manager at Invesco Taiwan.

Animal sacrifice

Hsinchu's mayor and science park officials took part in a televised rain-making ceremony last month, at which pigs, ducks and chickens were sacrificed, the Bloomberg news agency reported.

Yu Shyi-kun hopes to halt the drought

At another rain ceremony in the north of the island officials pledged to remain vegetarian for 10 days, according to local press reports.

Rainfall in Hsinchu County has been just one third of the usual level since November.

Water supplies to the Hsinchu Science-Based Industrial Park have been cut by 10% a day.

The impact of Taiwan's worst drought for 20 years could be felt by chip-designers in California.

"Many chip-design companies in Silicon Valley which depend on Taiwan Semiconductor Manufacturing Corp (TSMC) and UMC for production would be crippled" by shut-downs, said HSBC Asset Management Taiwan analyst Albert King.

The airforce will seed the clouds with dry ice while ground stations burn silver iodide, the chemical used to stimulate rainfall.