长江下游稻田不同种植制度的碳足迹分析  

Study on Carbon Footprint Under Different Cropping Patterns of Paddy Fields in the Lower Reaches of the Yangtze Rive

作　　者：严燕 季国军[2,3] 胡乃娟 陈留根[3] 郑建初[3] 胡锋[2] YAN Yan;JI Guo-jun;HU Nai-juan;CHEN Liu-gen;ZHENG Jian-chu;HU Feng(College of Humanities and Social Development,Nanjing Agricultural University,Nanjing 210095,China;College of Resources and Environmental Sciences,Nanjing Agricultural University,Nanjing 210095,China;Key Laboratory of Agricultural Environment of the Lower Reaches of the Yangtze River of Ministry of Agriculture and Rural Affairs of China/Jiangsu Academy of Agricultural Sciences,Nanjing 210014,China)

机构地区：[1]南京农业大学人文与社会发展学院,江苏南京210095 [2]南京农业大学资源与环境科学学院,江苏南京210095 [3]农业农村部长江下游平原农业环境重点实验室/江苏省农业科学院,江苏南京210014

出　　处：《长江流域资源与环境》2024年第7期1462-1473,共12页Resources and Environment in the Yangtze Basin

基　　金：教育部人文社会科学研究青年基金项目(20YJC810016);国家重点研发计划课题(2016YFD0300206)。

摘　　要：在保障粮食安全的同时降低碳排放是当前农业种植结构优化过程中迫切需要解决的问题。为探究长江下游稻田不同种植制度对温室气体排放的影响及其碳足迹,设置4种稻田种植制度处理:一年一熟的冬闲-水稻以及一年两熟的紫云英-水稻、冬油菜-水稻、冬小麦-水稻,连续两年采用静态暗箱-气相色谱法监测土壤甲烷(CH_(4))和氧化亚氮(N_(2)O)排放,运用生命周期评价法估算农田生产过程和农业生产投入引起的直接和间接温室气体排放,并进行碳足迹分析。结果表明:(1)一年两熟种植制度较一年一熟的冬闲-水稻增加周年CH_(4)排放17.5%~64.5%、N_(2)O排放60.7%~139.8%以及土壤有机碳固定量17.3%~37.2%;(2)在考虑土壤固碳的情况下,不同种植制度的土壤有机碳固定能抵消26.6%~35.6%的温室气体排放,冬小麦-水稻、冬油菜-水稻、紫云英-水稻单位面积净碳足迹两年平均分别为13.79、11.83和9.07 t CO_(2)-eq·hm^(-2),较冬闲-水稻(7.63 t CO_(2)-eq·hm^(-2))分别增加80.6%、55.0%和18.8%;(3)稻田生态系统碳足迹主要来自土壤CH_(4)排放(61.8%~67.4%),其次是氮肥施用(18.3%~23.9%),而后为N_(2)O排放(3.3%~5.2%)和柴油的使用(2.2%~2.8%);(4)一年两熟有利于增加周年产量和产值,非水稻季种植粮油作物能显著提高种植净收益,不同种植制度单位产量和单位产值碳足迹的差异不大。因此,冬闲-水稻是长江下游稻田最为低碳的种植制度,综合碳排放、粮食安全和经济产出,冬小麦-水稻、冬油菜-水稻明显优于冬闲-水稻;发展甲烷减排和氮肥减施技术是降低稻田生态系统碳足迹的重要途径。Reducing carbon emissions while ensuring grain security is currently an urgent problem that needs to be solved for optimizing agricultural planting structure.This study analyzed the influence of different cropping patterns on greenhouse gas emissions and carbon footprint of paddy fields in the lower reaches of the Yangtze River.Four treatments were considered including one single-cropping pattern(i.e.,winter fallow-rice)and three double-cropping patterns(i.e.,Chinese milk vetch-rice,winter rapeseed-rice and winter wheat-rice).Methane(CH_(4))and nitrous oxide(N_(2)O)emissions were simultaneously measured by static chamber and gas chromatography methods for two consecutive years.The life cycle assessment method was used to estimate the direct and indirect greenhouse gas emissions caused by field production process and agricultural inputs.The carbon footprint was then accordingly calculated.The results showed that:(1)Double-cropping patterns significantly increased the annual CH_(4) and N_(2)O emissions by 17.5%~64.5%and 60.7%~139.8%,and the annual soil organic carbon sequestrations by 17.3%~37.2%,respectively.(2)The soil organic carbon sequestrations under different cropping patters could offset 26.6%~35.6%of greenhouse gas emissions.When soil organic carbon sequestrations were taken into account,the average annual net carbon footprint per unit area for winter wheat-rice,winter rapeseed-rice,and Chinese milk vetch-rice was 13.79,11.83,and 9.07 t CO_(2)-eq·hm^(-2),respectively,which was 80.6%,55.0%,and 18.8%greater than that for winter fallow-rice(7.63 t CO_(2)-eq·hm^(-2)).(3)Soil CH_(4) emissions were the most important contributor to the carbon footprint of paddy fields(61.8%~67.4%),followed by nitrogen fertilizer application(18.3%~23.9%),N_(2)O emissions(3.3%~5.2%)and diesel combustion(2.2%~2.8%).(4)Double-cropping patterns could increase the annual grain yields and economic outputs compared with those of single-cropping pattern,while planting grain and oil crops in non-rice season significantly improved the an

关 键 词：碳足迹 粮食安全 种植制度 温室气体 土壤固碳 长江下游 

分 类 号：S181[农业科学—农业基础科学] S511