KARANG JATI, Indonesia (Reuters) - On a dry and dusty sports field in central Java, Indonesian men dressed as traditional warriors take turns to battle with wooden staves, while village women crowd around, chanting: "All farmers let us pray that rain comes and washes our sorrow away."

As in many parts of Java, Indonesia's main rice-growing island, seasonal rains are late coming to Karang Jati. A drought caused by the El Nino weather pattern, which scientists say could be the worst on record, means fields are fallow weeks after they would normally be sown. So the villagers have turned to a rain-making ritual to hasten the planting season.

Crop failures caused by an El Nino drought presage more pain for South-east Asia's largest economy, which is already growing at its slowest pace in six years, by squeezing incomes, fanning inflation and pushing more people into poverty.

All this piles pressure on Mr Joko Widodo, Indonesia's first president from humble origins, who made poverty reduction a priority but has seen it swell across this archipelago of 250 million people since he took office a year ago.

The number of people officially classed as poor actually rose in the first six months of his presidency to 28.6 million in March from 27.7 million in September 2014.

Twenty of Indonesia's 34 provinces are currently stricken by severe drought, according to the meteorology agency.

The World Bank says that if there is a severe El Nino this year, rice production will fall by 2.1 million tonnes, or 2.9 percent, and rice prices will rise by 10.2 per cent.

That price rise will hit the poor hardest because they spend more of their income on food than the well off. "Reduced agricultural incomes and higher prices could be devastating for poor households," the Bank said in a report, adding that rice imports may be needed if El Nino intensifies.

Mr Joko has provided more funds for cash transfers and social schemes, but so far has refused to sanction rice imports, keen that Indonesia should be self-sufficient in food.

"We are not talking about imports," Finance Minister Bambang Brodjonegoro told Reuters in a recent interview. "We are trying to make sure the domestic stocks are available and accessible."

Other countries at risk of an El Nino drought, such as the Philippines, have taken advantage of low global rice prices to boost stocks with foreign imports.

Such measures at least cap inflation if crops fail, though they mostly benefit people in towns who consume rice, rather than the farmers who produce it - all they can do is pray for the weather to change.

"Our padi fields depend on rainwater, so if there is no rain we suffer," said Mr Darijan, a 60-year-old farmer in central Java who has started selling his soil to brick-makers to make ends meet.

Agriculture accounts for nearly 14 per cent of Indonesia's gross domestic product, the highest among South-east Asia's five main economies.

One-third of the labour force works in farming, and more than half of poor households live off the land.

"What is very important ... to the poverty numbers is rice production and rice prices," Mr Steven Tabor, the Asian Development Bank's head in Indonesia, told a recent conference. "And the beginnings of El Nino seem to suggest that we may be in for rising poverty towards the end of the year."

As the drought drags on, Karang Jati's farmers such as 70-year-old Rohadi Rustam are anxious.

"If there's no rain, we have no money," he said, sitting by his sun-cracked fields. "That's how we farmers live."