| 摘要: |
| 开展稻田温室气体排放量化评估，明确稻田温室气体（greenhouse gases，GHGs）排放的构成、分布及其变化趋势，是推进农业绿色可持续发展的重要前提。基于生命周期评价法（life cycle assessment，LCA），筛选集成稻田CO2、CH4、N2O排放评估模型，提出市域尺度稻田GHGs排放核算框架，并量化分析2001—2017年台州市不同类型水稻GHGs排放的构成、分布及其变化趋势。结果表明：（1）水稻单位面积碳足迹呈现上升趋势，单位产量碳足迹呈下降趋势；单季稻单位面积碳足迹最高（8467 kg∙hm−2，以CO2计，余同），连作晚稻单位产量碳足迹最高（1.28 kg∙kg−1）。（2）2001—2017年台州市水稻田GHGs排放总量呈下降趋势，从1110.52 Gg（以CO2计，余同）降至557.23 Gg；2017年水稻GHGs排放主要集中于温岭市（131.39 Gg）、临海市（121.64 Gg），玉环市排放量最低（9.37 Gg），早稻和连作晚稻GHGs排放主要集中在温岭市，单季稻GHGs排放集中于临海市。（3）在农资投入碳足迹构成中化肥占比最大（50.46%），单位面积碳足迹结构中CH4占比最大（75.26%）。通过展开在市域尺度上水稻GHGs排放的核算过程，旨在为农田系统的碳排放提供更加精细化的计算方式，并为寻找更有效的碳减排路径及农田系统的可持续发展提供科学支撑。 |
| 关键词: 人地关系 低碳农业 温室气体排放 稻田系统 乡村人地系统 |
| DOI：10.7515/JEE222073 |
| CSTR： |
| 分类号: |
| 基金项目:德国联邦教育与研究部城市地区可持续发展计划项目“城乡共构”（01LE1804A1）；德国联邦教育与研究部“城市同伴”项目（01DO17037） |
|
| Evaluation method and empirical study of greenhouse gas emissions from a city-scale rice field system based on LCA: taking Taizhou City as an example |
|
ZHANG Lihua, YANG Zheng, NAN Qiong, CHENG Yu, LI Hongqing
|
1. College of Geography and Environment, Shandong Normal University, Jinan 250358, China
2. Key Laboratory of Pollution Ecology and Environmental Engineering of Chinese Academy of Sciences, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China
3. Chair of Circular Economy and Recycling Technology, Technical University of Berlin, Berlin 10623, Germany
4. College of Environmental & Resource Sciences, Zhejiang University, Hangzhou 310058, China
|
| Abstract: |
| Background, aim, and scope Carrying out a chemical assessment of greenhouse gas (GHGs) emissions from rice fields and clarifying the composition and distribution of GHGs from rice fields and their changing trends are important prerequisites for promoting the green and sustainable development of agriculture. Through the assessment of GHGs emissions from paddy fields at the municipal-scale, we can have a more intuitive understanding of the carbon emissions from paddy fields in the mesoscale region, thus providing scientific theoretical support for the sustainable development of rice production. Materials and methods The data were obtained mainly from statistical yearbooks and relevant literature, this study proposes a municipal-scale rice field GHGs emission accounting framework based on the screening of integrated rice field CO2, CH4 and N2O emission assessment models using the life cycle evaluation method, and quantitatively analyzes the composition and distribution of different types of rice GHGs emissions and their changing trends in Taizhou from 2001—2017. Results (1) The total GHGs emissions from rice fields in Taizhou City from 2001—2017 showed a decreasing trend, from 1110.52 Gg to 557.23 Gg; the carbon footprint (CF) per unit area showed an increasing trend and the CF per unit yield showed a decreasing trend; the CF per unit area was highest for single-cropping rice (8467 kg·hm−2) and the highest CF per unit yield for continuous late rice (1.28 kg·kg−1). (2) In 2017, GHGs emissions from rice were mainly concentrated in Wenling City (131.39 Gg) and Linhai City (121.64 Gg), with the lowest emissions in Yuhuan City (9.37 Gg), and GHGs emissions from early rice and continuous late rice were mainly concentrated in Wenling City. Single-cropping rice is concentrated in Linhai City. (3) Fertilizer accounts for the largest rate (50.46%) in the CF composition of agricultural inputs, and CH4 accounts for the largest rate (75.26%) in the CF structure per unit area. Discussion (1) GHGs emissions from paddy fields are closely related to the local GHGs emission factor, the quantity of agricultural materials inputs and rice yield. The higher amount of agricultural inputs made the paddy field GHGs emissions high. And lower rice yield caused higher CF per unit of yield. (2) In terms of standardization of rice data, all types of rice GHGs emission coefficients and conversion coefficients were accounted for using IPCC standards and relevant statistical yearbooks, and by comparing with the data of related studies in the whole country and various provinces and regions, our findings are consistent with them. Conclusions (1) GHGs emissions from rice fields have obvious characteristics of temporal changes. the total GHGs emissions from rice fields in Taizhou City from 2001 to 2017 showed a decreasing trend, from 1110.52 Gg to 557.23 Gg. The CF per unit area of all three types of rice had an increasing trend, and the CF per unit yield had a slight decreasing trend. (2) There are significant spatial differences in GHGs emissions from rice fields. 2017 GHGs emissions from rice are mainly concentrated in Wenling City and Linhai City, while Yuhuan City has the lowest emissions. (3) CH4 is the main contributor in the composition of GHGs emissions from rice fields, and the contribution of chemical fertilizers is also larger. Recommendations and perspectives Improving the utilization rate of production materials, mulching paddy fields, compound farming, returning organic fertilizer to the field after fermentation, appropriate level of nitrogen application, water-saving irrigation, and optimizing planting structure are effective ways to reduce carbon input and GHGs emissions from rice fields in Taizhou. |
| Key words: human-land relationship low-carbon agriculture GHGs emissions paddy system rural human-land system |
