中国农村生物质能利用与土壤固碳：基于循环农业的案例研究

吴光磊 程达 李立君 李彩虹 蒋高明 郑延海

中国政府推广农村户用沼气工程几十年，然而这些项目在缺乏沼气可持续生产技术下进展缓慢。本文选择一个典型的中国农村山东平邑县蒋家庄，从2008到2015，实验了一种新的沼气应用模式，即农村沼气生产与生态循环农业耦合技术。该循环模式中，作物/谷物残体以及人和牛排泄物，进入沼气池发酵，沼气作为家庭燃料，沼渣沼液作为优质有机肥料种植作物。丰富的农作物秸秆被用作牲畜饲料，其中的营养转化为人类可食的食物。以人/牛排泄物为底物，生产生活能源用沼气；沼气堆肥用作堆肥后的有机肥，提高土壤质量和作物产量。结果表明：秸秆作为饲料后，秸秆还田比例从2008的1.3%增加到2015的86.2%，养牛数量从3头增长到198头。沼气在家庭总能源中的比重，从2008年的1.1%在增加到2015年的62.3%；连续多年使用有机肥，土壤有机碳从83.8 Mg C/ha提高到213.5 Mg C/ha。我们的研究证明，循环农业可有效提升生物质能（作物残体）利用率，降低化石能源使用量（>50%）。循环农业是一个可持续的农业体系，可显著改善农村地区的环境条件。

JOURNAL OF RENEWABLE AND SUSTAINABLE ENERGY 10, 013107 (2018)

Biomass energy utilization and soil carbon sequestration in rural China: A case study based on circular agriculture

Guanglei Wu,1 Da Cheng,1,2 Lijun Li,1,2 Caihong Li,1 Gaoming Jiang,1 and Yanhai Zheng1,a)

1State Key Laboratory of Vegetation and Environmental Change, Institute of Botany,

Chinese Academy of Sciences, 20 Nanxincun, Xiangshan, Beijing 100093, People’s Republic of China

2University of Chinese Academy of Sciences, No. 19 Yuquanlu, Beijing 100049,

People’s Republic of China

Biogas projects have been promoted by the Chinese government in rural areas for several decades. However, these projects have proceeded slowly under the lack of biogas production technology. A circular agricultural experiment in combination with a local biogas promotion project was carried out in Jiangjiazhuang, a typical agricultural village in China, from 2008 to 2015. Agricultural production proceeded in an agricultural loop: “Crops/Grains/crop residues- Human/cattle excreta -Biogas digester- Biogas/biogas residues- Domestic fuels-organic fertilizers -Crops.” The abundant crop residues were used as cattle forage to turn the biomass energy into human-edible food. Human/cattle excreta was used as the substrate to produce biogas for livelihood energy. Biogas digester residues were used as organic fertilizers after composting to improve soil quality and crop yield. The results showed that the proportion of crop residues used for cattle forage increased from 1.3% in 2008 to 86.2% in 2015, while cattle population increased from 3 to 198. The proportion of biogas in total household energy increased from 1.1% in 2008 to 62.3% in 2015. Soil organic carbon increased under organic fertilizer application from 83.8Mg C hm_2 to 213.5Mg C hm_2. Our findings demonstrate that the promotion of circular agriculture may effectively enhance the utilization rate of biomass energy (crop residues) and reduce the consumption potential of fossil energy over 50%. Circular agriculture is a sustainable agricultural system that could improve the environmental conditions in rural areas.

JOURNAL OF RENEWABLE AND SUSTAINABLE ENERGY 10, 013107 (2018)