2004—2014年南方稻区双季稻生产碳足迹动态及其构成

南方稻作区是我国重要的粮食生产区,在国家粮食安全保障中起着至关重要的作用,探明南方不同省份双季稻生产的碳足迹差异,对促进低碳稻作农业发展具有重要意义.本研究采用2004—2014年农作物种植面积、农资投入等统计数据,运用碳足迹理论和生命周期法系统评价我国南方双季稻生产碳足迹时空分布状况及其构成.结果表明: 南方稻区各个省份早晚稻生产碳足迹大部分表现为增加趋势,早稻生产碳足迹较晚稻大.2004—2014年,安徽省双季稻平均碳足迹最高(1000 kg CO₂-eq·hm^-2),而福建、湖北和湖南省相对较小(750 kg CO₂-eq·hm^-2).碳足迹构成中以肥料的生产、运输及使用占比最大,占水稻生产总碳足迹的60%;柴油投入碳足迹贡献量次之,为26%左右.逐步回归分析表明,双季稻生产碳足迹大小与柴油、复混肥和钾肥的投入呈正相关.净利润收益纳入分析表明,湖北省为低排放-高收益省份,有利于农业低碳可持续性发展.随着农村劳动力非农化和作物生产机械化的快速递增,未来水稻生产中柴油等机械化碳投入将快速增长.因此,提升化肥利用效率、灌溉效率和机械化作业效率将是发展南方稻作区低碳农业的关键途径.

Dynamic of carbon footprint and its composition for double rice production in Southern China during 2004-2014

The area of rice production in Southern China is one of the most important farming regions in China, due to its great contribution to national food security. To assess the differences in carbon footprints (CF) of double rice production will benefit the achievement of low carbon agriculture. Base on the statistical data of crop yield and farmland investment of double rice production from 2004 to 2014, the spatiotemporal dynamics of CF and its composition of double rice in Southern China was estimated using the theory of CF and life cycle assessment method. The results showed that the CF of early and late rice in each province tended to increase, with the CF of early rice being higher than that of late rice. CF of early and late rice in Anhui were the highest (1000 kg CO₂-eq·hm^-2), and those in Fujian, Hubei and Hunan were the lowest (750 kg CO₂-eq·hm^-2). The highest component of CF in double rice was the production, transportation and utilization of fertilizers (60%), followed with the consumption of diesel. Progressive regression analysis showed that CF of double rice from 2004 to 2014 was mainly affected by diesel, compound fertilizer and K₂O fertilizer. The analysis of net profit income showed that Hubei was a province with low-emission and high-yield, which was conducive to the sustainable development of low carbon agriculture. Given to the large transfer of rural labor from agricultural to non-agricultural sections and the development of mechanization, diesel and other mechanical inputs would increase rapidly in the future. Therefore, improving fertilizer utilization, mechanical and irrigation efficiencies in crop production would be the main approach to promote low-carbon agriculture in rice production of southern China.