中文摘要：

耕地撂荒是当前全球山区主要的土地利用变化现象，它深刻地改变了山区农村土地利用结构、农业景观和农户生计，并带来了巨大的生态环境和社会经济效应。2000年以来，随着中国劳动力成本的快速上升和农村劳动力的大量析出，中国山区农业因地形限制，机械化发展受阻，耕地面临着较大的撂荒风险。越来越多的案例研究和报道表明中国山区耕地撂荒现象越演越烈。中国山区面积广、坡耕地比重大，耕地撂荒不仅关系到山区农地的合理利用政策和山区可持续发展政策的制定，并可能引起粮食安全问题，但目前仍缺少全国层面的定量化评估研究。因此，本研究通过开展大范围的抽样调查对中国山区县撂荒规模进行了推算，以期为相关政策制定以及耕地边际化进一步研究提供参考。研究结果表明，在235个调查村庄中，78．3％的村庄出现耕地撂荒现象；基于县样本统计的2014-2015年全国山区县耕地撂荒率为14．32％；山区耕地撂荒率在省级尺度上呈现出南高北低的空间格局。其中，长江流域一带的山区耕地撂荒率最高，东北的长白山区最低。

英文摘要：

Cropland abandonment is the main land-use change in mountainous areas globally. It has profoundly altered rural land-use structure, agricultural landscapes, and farmer livelihoods in mountainous areas and has huge environmental and socioeconomic impacts. Since 2000, with the rapid rise in labor costs and the exodus of the rural labor force, croplands in China＇ s mountainous areas have been facing a greater risk of abandonment due to rough terrain and slow development of agricultural mechanization. Case studies and reports have increasingly demonstrated that cropland abandonment in these areas is severe. Considering that sloping croplands account for about 25% of total croplands in China, cropland abandonment is not only related to informed policy-making regarding land use and sustainable rural development in mountainous areas, but possibly has a significant negative impact on food security. Quantitative analyses of cropland abandonment at a national level in China have not been performed. Hence, in this study, a large-scale survey was carried out to estimate the extent of cropland abandonment in mountainous counties to offer a scientific basis for relevant policy-making and further study of cropland marginalization. The results show that 78.3% of 235 surveyed villages have experienced cropland abandonment to some extent. During 2014-2015, the abandonment rate of croplands in mountainous counties was 14.32%, showing a distribution pattern of ＂south-high and north-low＂ at the provincial level. The abandonment rate for the Yangtze River Basin was the highest, while that for the northeastern mountainous area was the lowest.