摘要
长江中游稻作模式由传统中稻-冬季作物模式向再生稻发展的趋势明显,但关于稻作模式对稻田CH_(4)和N_(2)O排放的研究尚缺乏报道。以江汉平原3种模式为对象:稻-麦(RW)、稻-油(RR)和再生稻(Rr),采用静态箱-气相色谱法,研究稻田CH_(4)和N_(2)O排放的变化规律,同时监测土壤硝态氮(NO^(3-)-N)、铵态氮(NH_(4)^(+)-N)、pH和土温的动态变化,以期揭示不同稻作模式对温室气体排放的影响及影响因素。结果表明,在非水稻季,RW、RR和Rr处理的CH_(4)的累计排放量分别为6.34、9.35和8.63 kg·hm^(-2),N_(2)O平均排放通量分别为8.08、17.78和24.92μg·m^(-2)·h^(-1),表现为Rr>RR>RW;在水稻季,相比较RR处理,RW和Rr处理CH_(4)的累计排放量分别增加了158.27%和148.38%,且差异显著,其N_(2)O的累计排放量分别增加了34.89%和87.36%。Rr处理头季CH_(4)的排放量占整个水稻季87.64%,其N_(2)O平均排放通量头季要比再生季高35.99%。RW和Rr处理产量差异不显著,但要显著高于RR处理,其增幅分别为14.49%和24.40%。RR的全球增温潜势(GWP)和温室气体排放强度(GHGI)最低,其GWP比RW、Rr分别低45.05%和72.85%;GHGI分别降低了35.14%和63.64%。中稻季CH_(4)的排放速率与NH_(4)^(+)-N含量呈显著正相关(P<0.05),Rr处理下CH_(4)的排放量与NO^(3-)-N含量呈显著负相关关系(P<0.05),与土壤pH呈负相关,且差异极显著(P<0.01);中稻季N_(2)O的排放与NO^(3-)-N和土温负相关,差异不显著(P>0.05),Rr处理N_(2)O排放与NH_(4)^(+)-N呈显著正相关(P<0.05)。因此,在江汉平原稻-油模式不仅利用了冬闲田,提高作物种植产量,还有利于降低温室气体的排放,缓解全球增温潜势。
The rice cropping pattern in the middle reaches of the Yangtze River showed an obvious trend from the traditional medium rice-winter crop pattern to the regrowing-rice pattern.However,there were few reports on the effects of rice cropping pattern on CH_(4) and N_(2)O emissions from paddy fields.Three models of Jianghan Plain were taken as objects:Rice-wheat(RW),rice-rape(RR)and regrowing rice(Rr),to study the changes of rice cropping patterns effects on CH_(4) and N_(2)O emissions in paddy fields using static boxgas chromatography.Meanwhile,the dynamic changes of soil NO^(3-)-N,NH_(4)^(+)-N,pH and soil temperature were monitored,in order to reveal the effects and influencing factors of different rice cropping patterns on greenhouse gas emissions.The results showed that in the non-rice season,the cumulative CH_(4)emissions of RW,RR and Rr were 6.34 kg·hm^(-2),9.35 kg·hm^(-2)and 8.63 kg·hm^(-2),respectively.The average N_(2)O emission fluxes were 8.08μg·m^(-2)·h^(-1),17.78μg·m^(-2)·h^(-1) and 24.92μg·m^(-2)·h^(-1),respectively,in the order of Rr>RR>RW.In the rice season,compared with RR,the cumulative CH_(4)emissions of RW and Rr increased by 158.27%and 148.38%,respectively,and the cumulative N_(2)O emissions of RW and Rr increased by 34.89%and 87.36%,respectively.The CH_(4)emission of Rr in the first season accounted for 87.64%of the whole rice season,and the average N_(2)O emission flux in the first season was 35.99%higher than that in the regeneration season.The yields between RW and Rr shown no obvious difference,but were significantly higher than that of RR,which increased by 14.49%and 24.40%.RR had the lowest global warming potential(GWP)and greenhouse gas emission intensity(GHGI).GWP of RR was 45.05%and 72.85%lower than those of RW and Rr,respectively,while GHGI decreased by 35.14%and 63.64%,respectively.There was a significant positive correlation between CH_(4)emission and NH_(4)^(+)-N content in middle rice season(P<0.05),and a significant negative correlation between CH_(4)emission and NO^(3-)-N content in Rr(P<0.05),a significant negative correlation between CH_(4)emission rate and soil pH(P<0.01).The N_(2)O emission was negatively correlated with NO^(3-)-N and soil temperature in middle rice season,and the difference was not significant(P>0.05),while the N_(2)O emission was significantly and positively correlated with NH_(4)^(+)-N in Rr(P<0.05).Therefore,the RR model in Jianghan Plain not only makes use of idle winter farmland to increase crop yield,but also helps reduce greenhouse gas emissions and mitigate the global warming potential.
作者
李成伟
刘章勇
龚松玲
杨伟
李绍秋
朱波
LI Chengwei;LIU Zhangyong;GONG Songling;YANG Wei;LI Shaoqiu;ZHU Bo(Hubei Collaborative Innovation Center of Grain Crop Industrialization of Yangtze University,Jingzhou 434200,P.R.China;Engineering Research Center of Wetland Ecology and Agricultural Utilization,Ministry of Education/Yangtze Universit,Jingzhou 434200,P.R.China)
出处
《生态环境学报》
CSCD
北大核心
2022年第5期961-968,共8页
Ecology and Environmental Sciences
基金
国家自然科学基金项目(31870424)
国家重点研发计划(2017YFD0301400)
湿地生态与农业利用教育部工程研究中心开放基金项目(KFT201904)。