摘要
稻田被认为是温室气体CH_4和N_2O的主要排放源之一。湖北省江汉平原地区水稻常年种植面积约8×105 hm2,占湖北省水稻种植面积的40%左右。研究江汉平原地区稻田温室气体排放特征,对于评估区域稻田温室气体排放以及稻田温室气体减排具有重要意义。目前,DNDC模型已被广泛应用于模拟和估算田间尺度的温室气体排放,DNDC模型与地理信息系统(Arc GIS)结合,可进行区域尺度的温室气体排放模拟与估算。本研究以湖北省典型稻作区江汉平原为研究区域,运用DNDC模型模拟和估算江汉平原稻田区域尺度的温室气体排放。设置大田定点观测试验,监测中稻-小麦(RW)、中稻-油菜(RR)、中稻-冬闲(RF)3种种植模式下稻田温室气体CH_4和N_2O的周年排放特征。通过田间观测值与DNDC模拟值的比较进行模型验证,并利用获取DNDC模型所需的气象、土壤、作物及田间管理等区域数据,模拟江汉平原稻田不同种植模式下温室气体CH_4和N_2O的排放量。田间试验表明,江汉平原稻田RW、RR和RF模型的CH_4排放通量为-2.80~39.78 mg·m-2·h-1、-1.74~42.51 mg·m-2·h-1和-1.57~55.64 mg·m-2·h-1,N_2O周年排放通量范围分别为0~1.90 mg·m-2·h-1、0~1.76mg·m-2·h-1和0~1.49 mg·m-2·h-1;CH_4排放量RW和RR模式显著高于RF模式,N_2O排放量为RF显著低于RW和RR模式。模型验证结果表明,不同种植模式温室气体排放实测值与模拟值比较的决定系数(R2)为0.85~0.98,相对误差绝对值(RAE)为8.29%~16.42%。根据DNDC模型模拟和估算的结果,江汉平原区域稻田CH_4周年的排放量为0.292 9 Tg C,N_2O周年的排放量为0.009 2 Tg N,不同种植模式稻田CH_4排放量表现为RW>RR>RF,N_2O排放量表现为RW>RF>RR,增温潜势(GWP)表现为RW>RR>RF。不同地区稻田CH_4排放量表现为监利县>荆门市>公安县>天门市>仙桃市>洪湖市>松滋市>汉川市>潜江市>石首市>荆州市>江陵县>赤壁市>嘉鱼县,N_2O排放量表现为监利县>荆门市>公安县>洪湖市>仙桃市>天门市>汉川市>潜江市>松滋市>荆州市>江陵县>赤壁市>石首市>嘉鱼县。本研究结果表明DNDC模型能较好地应用于模拟江汉平原稻田温室气体排放,RR和RF模式相比RW模式可有效减少温室气体CH_4和N_2O的排放。
Increased greenhouse gases emission contributes to global warming.Paddy field is considered to be one of the main sources of greenhouse gas CH4 and N2O emissions.The rice planting area in the Jianghan Plain is about 8×105 hm2,accounting for about 40%of the total rice planting area in Hubei Province.Studies on characteristics of greenhouse gases emission in the Jianghan Plain are important for evaluation and reduction of regional greenhouse gases emission.So far,several models,such as DNDC model,have been used for simulating the greenhouse gases emission,which in conjunction with ArcGIS may be used for simulating the regional greenhouse gas emission.In this study,we used DNDC model to simulate the greenhouse gases emission in the Jianghan Plain.The field experiment was carried out for investigating the characteristics of CH4 and N2O emissions under rice-wheat(RW),rice-rape(RR)and rice-fallow(RF)cropping systems.Meteorologic,soil,crop and field management data were obtained for DNDC-stimulating CH4 and N2O emissions under different cropping systems in the Jianghan Plain.The results of field experiment showed that the CH4 fluxes were from?2.80 mg·m?2·h?1 to 55.64 mg·m?2·h?1,and the N2O fluxes were from 0 to 1.90 mg·m?2·h?1 in the Jianghan Plain.CH4 emission was mainly concentrated in rice season,and the peaks occurred at rice heading and tillering stages.N2O emission in rice season was higher than in non-rice season.And the peaks occurred after wheat or rape sowing in non-rice season and during field drying period in rice season.CH4 emission under RW and RR systems were significantly higher than that under RF system,while N2O emission was significantly higher under RF system than under RW and RR systems.The DNDC model stimulating results were verified by comparing the observed values with the stimulated values.The R2 and RAE between the observed and the stimulated values under different cropping systems were form 0.85 to 0.98 and from 8.29%to 16.42%,respectively.The high R2 and the low RAE suggested that the stimulated values of CH4 and N2O emissions with DNDC model were in good agreement with the observed values.According to the simulation results,the annual emissions of CH4 and N2O were 0.292 9 Tg C and 0.009 2 Tg N in the Jianghan Plain from 2010 to 2016,respectively.For different crop systems,CH4 and N2O emissions were presented as RW>RR>RF and RW>RF>RR,respectively,and the global warming potential(GWP)was RW>RR>RF.The CH4 and N2O emissions were also different for different regions.The annual average CH4 emission from 2010 to 2016 was in the order of Jianli>Jingmen>Gong’an>Tianmen>Xiantao>Honghu>Songzi>Hanchuan>Qianjiang>Shishou>Jingzhou>Jiangling>Chibi>Jiayu.And the annual average N2O emission from 2010 to 2016 was in the order of Jianli>Jingmen>Gong’an>Honghu>Xiantao>Tianmen>Hanchuan>Qianjiang>Songzi>Jingzhou>Jiangling>Chibi>Shishou>Jiayu.The results of our study indicated that the DNDC model could preferably stimulate the greenhouse gases emissions in the Jianghan Plain.And RR and RF could reduce CH4 and N2O emissions compared with RW.
作者
邹凤亮
曹凑贵
马建勇
李成芳
蔡明历
汪金平
孙自川
江洋
ZOU Fengliang;CAO Cougui;MA Jianyong;LI Chengfang;CAI Mingli;WANG Jinping;SUN Zichuan;JIANG Yang(College of Plant Science and Technology,Huazhong Agricultural University,Wuhan 430070,China)
出处
《中国生态农业学报》
CSCD
北大核心
2018年第9期1291-1301,共11页
Chinese Journal of Eco-Agriculture
基金
国家重点研发计划专项(2017YFD0301400)资助~~
