BEIJING - Land disputes have emerged as rural China's most volatile social problem, as forced acquisitions have been generating growing social unrest, China's top think tank said in its annual report on Wednesday.

The Chinese Academy of Social Sciences (CASS) said in its 2011 Blue Book of China's Society that 73 percent of the petitions and complaints farmers filed are related to land.

The report also said the meager compensations and unsatisfactory resettlement conditions common in land transfers are farmers' two primary points of discontent.

Land skirmishes accounted for 65 percent of rural mass conflicts, which undermine the country's social stability and economic development, the report pointed out.

Since the central government has set a "red line" to reserve 120 million hectares of arable land - the minimum necessary to guarantee grain safety - some local authorities have been grabbing land covered with rural houses or plots designated for housing purposes, the report said.

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Tens of thousands of farmers, whose families have dwelled in scattered farmhouses for generations, are being relocated to multistory buildings to vacate land local governments sell to developers for profit.

Kong Xiangzhi, vice-dean of the School of Agricultural Economics and Rural Development at Renmin University of China, told China Daily that living in apartment buildings is not what farmers want and it substantially raises their costs of living.

"When farmers live in multistory buildings, they have to pay for everything from water to electricity," Kong said.

"They can no longer raise livestock or dig wells, and live as they had on farms in houses with courtyards."

The countryside's land battles can be deadly.

A 35-year-old woman committed suicide in Batou village, East China's Jiangsu province, in 2009 because her family could not afford an apartment with the compensation money they received after the whole village was relocated, the Beijing News reported.

In Longqiao village, Central China's Hunan province, 74 farmers decided to sue the local government this November after they were neither properly compensated nor well relocated when their village was torn down for the construction of expressway toll booths, the Legal Weekly reported.

Over the past 20 years, more than 6.67 million hectares of land has been seized from farmers, while disparity between the combined compensation and market price has stood at around 2 trillion yuan ($294 billion), the Beijing News quoted CASS' Rural Development Research Institute researcher Yu Jianrong as saying.

The annual report also said the proliferating land disputes have damaged relationships between local governments and villagers.