Abstract: Influenced by increasing thirst for energy to fuel fast growing economy and pressure of reducing greenhouse gas emissions, biofuel production expanded rapidly these years. The total bio-ethanol production increased from 5.68×10⁸ L in 1975 to 170×10⁸ L in 2000 and to 511×10⁸ L in 2007. The biodiesel increased from 9.1×10⁸ L in 2000 to 132×10⁸ L in 2007. The rapid increase of biofuel aroused hot debates on its effect on food security. This paper analyzed the debates of biofuel production, area of land used for biofuel production, its impact on land use changes and the international mechanism of farmers’ land use decisions. Results show that as one of the main input of biofuel production, land use change is the medium of its influence on food security, environment and other social dimensions. Secondly, the arable land used for biofuel production has been increased rapidly these years. In 2004, there was 1400×10⁴hm² of arable land used for biofuel production, accounted for 1% of the total arable land (140583×10⁴hm²). In 2007, figure increased to 4221.7×10⁴hm². It is projected that fuel crops’ sown area may account for 15%-20% of the total sown area in some countries in the near future. Fuel crops will become one of the main crops. Thirdly, extension of the sown area of fuel crops caused remarkable land use changes. Large area of forest, grassland and unused land was converted to agricultural land. In the internal planting structure, food crops were converted into fuel crops. Fourthly, household is the basic decision maker of land use changes. Attracted by higher income, famers are more inclined to plant crops that have more net income. From the input-output comparison of main food and fuel crops in Guangxi, net income of fuel crops is much higher than food crops. In 2009, the net income of cassava was 11123.04 yuan/hm² and sugarcane 12138.36 yuan/hm², more than rice (6984.04 yuan/hm²), maize (5104.61 yuan/hm²) and peanut (2851.36 yuan/hm²). This is the basic reason for the increase sown area of fuel crops. Finally, the paper proposed that further studies were needed to be done on the quantitative analysis of the competition of biofuel crops and food crops, the internal mechanism of farmers’ land use decisions, the impact of biofuel production on future land use changes in the process of urbanization.

Key words: land use changes, biofuel, food security, input-output analysis