不同稻作系统土壤的CH4产生潜力与产生途径  

Methane Production Potential and Methanogenic Pathways in Paddy Soils Under Different Rice-based Cropping Systems

作　　者：沈皖豫 黄琼 马静[1] 张广斌[1] 徐华[1] SHEN Wan-yu;HUANG Qiong;MA Jing;ZHANG Guang-bin;XU Hua(State Key Laboratory of Soil and Sustainable Agriculture,Institute of Soil Science,Chinese Academy of Sciences,Nanjing 210008 China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院南京土壤研究所土壤与农业可持续发展国家重点实验室,南京210008 [2]中国科学院大学,北京100049

出　　处：《环境科学》2022年第7期3835-3843,共9页Environmental Science

基　　金：国家自然科学基金项目(41877325);中国科学院青年创新促进会项目(2018349);国家重点研发计划项目(2017YFD0300105)。

摘　　要：不同稻作系统土壤的CH_(4)产生潜力,特别是CH_(4)产生途径(主要为乙酸发酵和CO_(2)/H_(2)还原)间的差异尚不明确.通过添加与不添加氟甲烷(CH_(3)F)抑制剂(添加比例分别为2%和0%)的土壤厌氧培养试验,并采用稳定性碳同位素等方法,对我国3类典型稻田生态系统(稻-麦轮作,RW;稻-休闲,RF;双季稻,DR)土壤CH_(4)产生累积浓度、CH_(4)产生潜力、溶解性有机碳(DOC)含量、乙酸含量和乙酸产CH_(4)的相对贡献率(f_(ac)值)进行了对比研究.结果表明,RF的CH_(4)产生潜力为7.18μg·(g·d)^(-1),显著低于RW[10.33μg·(g·d)^(-1)]和DR[13.42μg·(g·d)^(-1)](P<0.05);相关分析表明,CH_(4)产生潜力与土壤阳离子交换量及pH呈显著负相关(P<0.01);添加CH_(3)F显著抑制CH_(4)产生(P<0.05).DR的ω(DOC)和ω(乙酸)分别为255 mg·kg^(-1)和7.34 mg·kg^(-1),较RW和RF分别高17%~51%和22%~23%(P<0.05).δ_(13)CH_(4)和δ_(13)CO_(2)值受稻作系统的影响显著,其中,RF的δ_(13)CH_(4)值最大(-43.89‰),较RW和DR分别偏正11.06‰和8.33‰(P<0.05);而其δ_(13)CO_(2)值最小(-26.30‰),较RW和DR分别偏负7.63‰和5.14‰(P<0.05).RW和RF的α(CO_(2)/CH_(4))值分别为1.057和1.058,显著低于DR的1.062(P<0.05).RF的f_(ac)值为84%~98%,较RW和DR分别高34%~38%和20%~23%(P<0.05).Differences inmethane(CH4)production potential in paddy soils under different rice-based cropping systems and especially in the methanogenic pathways(mainly acetate fermentation and CO_(2)/H_(2) reduction)remain unclear.Anaerobic incubations of soil with or without fluoromethane(CH_(3)F)inhibitor(2%and 0%)were conducted.With the soils from three typical paddy ecosystems(rice-wheat rotation,RW;rice-fallow,RF;double-rice,DR)in China,the cumulative concentration of CH_(4) production,CH_(4) production potential,dissolved organic carbon(DOC)content,and acetic acid content were determined.Meanwhile,the relative contribution of acetate-dependent methanogenesis(f_(ac))was quantified using the stable carbon isotope method.The results showed that the CH_(4) production potential was 7.18μg·(g·d)^(-1) in RF,which was significantly lower than that in RW[10.33μg·(g·d)^(-1)]and DR[13.42μg·(g·d)^(-1)](P<0.05).Correlation analysis showed that CH4 production potential was significantly negatively correlated with soil cation exchange capacity and pH(P<0.01);the addition of CH3F significantly inhibited CH4 production(P<0.05).The content of DOC and acetic acid in DR were 255 mg·kg^(-1) and 7.34 mg·kg^(-1),respectively,which were 17%-51%and 22%-23%higher than those in RW and RF,respectively.Theδ13CH4 andδ13CO_(2) values were affected greatly by different rice-based cropping systems,and the highestδ13CH4 value was-43.89‰in RF,which was more positive than that of RW and DR by 11.06‰and 8.33‰,respectively(P<0.05).By contrast,the lowest value ofδ13CO_(2) was observed in RF,which was more negative than that of RW(7.63‰)and DR(5.14‰)(P<0.05).Theα(CO_(2)/CH4)values of RW and RF were 1.057 and 1.058,respectively,which were significantly lower than 1.062 in DR(P<0.05).The fac values of RF ranged from 84%to 98%,being 34%-38%and 20%-23%higher than those of RW and DR,respectively(P<0.05).

关 键 词：乙酸产CH_(4)途径 土壤性质 稻田生态系统 氟甲烷 稳定性碳同位素组成 

分 类 号：X16[环境科学与工程—环境科学]