His desk is piled up with mail but a brief look at the return addresses is always enough to disappoint Li Yingxin - the letter he is expecting from the Ministry of Education has never arrived.

The grass-root official in Gansu Province wrote to the top education authorities four months ago, appealing for better pay for the 600-odd farmer teachers in his county, 70 per cent of whom make only 40 yuan (US$5) a month.

They are temporary teachers in rural areas as they have not received the required training to get on the state pay roll as full-time, qualified teachers.

But since they are better educated than the average villagers, they fill openings left unwanted by college graduates.

"This is a disadvantaged group living at the bottom rung. They are working all-out but earn hardly enough to live on," Li wrote in the letter. "In every single village of our county, a farmer teacher's family is always the poorest."

Many of them should have been promoted to become permanent teachers many years ago, but for one reason or another, they have remained marginalized, some until after their retirement age.

Wang Zhengming, 62, is one of them. The veteran rural teacher should have been upgraded two decades ago. In 1984, the year he was supposed to become a permanent teacher, he was relieved of his duties at the village school where he had been teaching for more than 20 years as fully qualified teachers were taken on to fill all the positions.

"But all the new teachers resigned the very next year, so I was told to go back teaching there," Wang told Xinhua News Agency in an interview.

But he had missed the opportunity for promotion and has remained on 40 yuan a month ever since.

"I've been shocked, time and again, by their poverty and perseverance, and am deeply concerned about the hardship western China is enduring to offer nine-year compulsory education to all school-age children," said Li, a university teacher who is taking a one-year post in the outback Weiyuan County of Gansu Province.

Local education department figures say the 32,000 farmer teachers in this northwestern province are teaching at least 1 million school-age children, one third of the province's total. But even the highest earner makes only 200 yuan (US$25) a month.

The county coffers can do little to finance education. The annual revenue of Weiyuan County is 20 million yuan (US$2.5 million), enough only to cover one month's salary for its 3,000 permanent teachers and 1,000 public servants. "Even these permanent employees have to be paid, for 11 months of the year, with appropriations from the central coffers," said Li.

But despite no response as yet to his letter from the Ministry of Education, he is still optimistic of change in the future.

"And so are all the farmer teachers who know my campaign," he added.

The primary school Li Xiaofeng has been teaching at for the past 13 years is probably the smallest in China its 24 students, from first to fifth-graders, share one classroom and one teacher.

He also acts as principal and caretaker at the Shiziyuan village-run primary school, locked in the hinterland of Qinling Mountain in Northwest China's Shaanxi Province

Altogether 134 students have graduated from here, four of whom have entered college - fulfilling a dream of Li.

Li, a straight-A senior high school graduate, did not take the college entrance exam in 1992: he took up teaching in order to repay 10,000 yuan (US$1,230) of debts his father left behind after years of illness.

Hard work has aged him ahead of his time. At 32, Li looks more like a man in his 40s. Despite his local fame as an exemplary teacher, his temporary job promises no social security or any compensation other than 103 yuan (US$12.7) a month.

But even that meagre wage has been in arrears since the beginning of 2004, because the country has since moved to replace farmer teachers with new graduates and the local government has cut budgets accordingly.

Li admitted he had considered giving up the job. "My fiancee left me in 1997, saying I could never bring home the bread. It's the most face-losing experience for a man."

That summer Li found a job in Xi'an, capital of Shaanxi Province, that paid 10 times more. But village officials came to him a few days after the new school year started. "They said they tried to find someone to fill my vacancy but no one was willing to come," Li said.

After a sleepless night, Li made the decision of his life, and returned. "The children needed me. Without an education, they'll be shepherds all their lives."

He is just one of the 500,600 farmer teachers in western China, a largely underdeveloped region where education is crucial in lifting the locals out of poverty.

For Yu Jianchao, the start of every semester brings with it a sense of fear. The education official in Weiyuan County, Gansu Province, is worried that some of the 54 underpaid farmer teachers in the impoverished Beizhai Township might quit.

"If they do, I'd have no convincing reason to hold them back - they are paid only 40 yuan a month, while the 101 permanent teachers earn 30 times as much. But the kids won't be able to attend school if they quit," he said.

Wang Weihong, 39, said he is planning to build his fortune next year by picking cotton in Xinjiang or applying for a better-paid position at a private school. "My colleague, Chen Lianru, makes 2,400 yuan (US$ 300) a month at a private school in the city of Jiuquan. He's repaid all his debts and had a new house built."

It leaves Yu sometimes feeling he is fighting a losing battle.

"All that I can do is to cut office spending and buy each of them 25 kilograms of flour at the Chinese New Year, telling them the children need them."

The brain drain among underpaid farmer teachers has even compelled some village-run schools to hire junior high school dropouts to step in to help, downgrading the quality of school education.

China is currently revising its Compulsory Education Law to promote nine-year compulsory education among all school-age children and offer them equal access to schooling.

The Ministry of Education has said in a national report that it will try to ensure compulsory education to all in western China by 2005 and across the country by 2010.

It aims to reduce the illiteracy rate among the young and middle-aged population to below 2 percent and that of adults to less than 5 percent.

"The government should exempt all expenses for the nine-year compulsory education period if it really aims to make it accessible to all," said Yang Chengming, a professor of law at the Beijing Institute of Technology.

Educationist Yang Dongping said the central and provincial governments now foot 2 percent and 11 percent respectively of the bills for compulsory education. "The remaining 87 percent are paid by local governments at county level, the most disadvantaged party in terms of financial capacity."

In fact, compulsory education should be funded by the central government alone, said Yang, an education specialist with Beijing Institute of Technology. "It will cost about 30 billion yuan (US$3.7 billion) a year, not a big deal for a country with 2 trillion yuan (US$247 billion) of annual fiscal revenue."

Wu Hua, of Zhejiang University in east China, said teachers' salaries, which make up about 80 percent of the total compulsory education spending, should be paid by the central government while the provincial governments may pay the remaining 20 percent.