Compensation for farmers whose land is expropriated has increased by more than 30 percent since 2008 as a result of land acquisition reforms, a top official said Tuesday. Xu Shaoshi, minister of Land and Resources, said farmers\' compensation and subsidies resulting from land expropriation and demolitions hit 3.5 trillion yuan (about 561 billion U.S. dollars) between 2008 and 2011. More than 25 million farmers were covered by the social security network during the same period after their land was expropriated, said Xu, citing a State Council report on land administration that was submitted to the ongoing session of the top legislature for deliberation. Xu said the reforms have adhered to the principles of \"narrowing the scope of land expropriation, standardizing expropriation procedures, raising compensation standards and ensuring the farmers\' relocation.\" \"Pressure stemming from the illegal occupation of arable land remains high in China,\" Xu said. \"There is a sharp contradiction between the supply and demand of land for construction, with both urban and rural construction occupying farmland,\" he said. Land supplies for real estate construction has remained high in recent years, according to the report.Land expropriation and demolitions have given rise to prominent problems, including public petitions, massive protests and riots, according to Xu. \"The non-standard transfer of construction land under collective ownership has sparked a great deal of conflict and disputes,\" he said. The government will accelerate land acquisition reforms, standardize the transfer of construction land under collective ownership and promote the construction of a unified urban and rural land market, Xu said. He said the government will consider setting up a unified real estate registration system by identifying and registering construction land under collective ownership, farmers\' housing and contracted sites. About 86 percent of land under collective ownership was identified and registered as of October, the report said. To ensure grain security, China has set a \"red line\" to guarantee that its arable land never shrinks to less than 1.8 billion mu (120 million hectares). But the country is facing growing challenges due to rapid urbanization and massive infrastructure construction. The country is already edging dangerously close to the tipping point, with just 1.82 billion mu available as of 2011, figures from the report showed.