水分管理对稻田土壤CH_4产生、氧化及排放的影响

Effects of water management on production, oxidation, and emission of CH_4 from rice paddy soil

水分是稻田CH4产生、氧化和排放最为重要的影响因素之一,但有关水分对稻田土壤CH4产生潜力、氧化潜力的大小及其季节变化影响的相关报道较少。分别通过室内厌氧培养试验、好氧培养试验和田间原位试验(位于江苏省句容市白兔镇),于2007年水稻生长期观测了2种水分管理方式(间隙灌溉和持续淹水)下种稻(水稻品种为华粳3号,Oryzasativa L.Huajing3)土壤的CH4产生潜力、氧化潜力及排放通量。结果表明:烤田前,两处理土壤CH4产生潜力和氧化潜力的大小及其季节变化趋势一致,使得两处理CH4排放通量的大小及其季节变化趋势一致;烤田后,持续淹水处理土壤CH4产生潜力明显大于间隙灌溉处理,而CH4氧化潜力明显低于间隙灌溉处理,导致CH4排放通量显著高于间隙灌溉处理(p<0.05)。烤田明显降低土壤CH4产生潜力,提高土壤CH4氧化潜力,故显著减少稻田CH4排放通量(p<0.05)。水分管理通过同时影响CH4产生潜力和氧化潜力来影响稻田CH4排放。

Water regime is one of the most important factors that affect production, oxidation, and emission of CH4, but few research reports are available in the literature about effects of water regime on values and seasonal variation of CH4 production potential and CH4 oxidation potential in rice paddy soil. Anaerobic and aerobic incubation trials as well as a field experiment, laid out at Baitu Town, Jurong City, Jiangsu Province, were carried out separately to study and measure CH4 production potential, CH4 oxidation po- tential, and CH4 emission of the soil with rice Oryza sativa L. （Huajing 3） planted and subject to two water treatments （intermittent irrigation, II; and continuous flooding, CF） during the rice-growing season in 2007. Before the mid-season aeration stage, the two treatments were similar in value and seasonal variation of CH4 production potential and CH4 oxidation potential, thus leading to little difference between the two treatments in value and seasonal variation of CH4 emission. After the mid-season aeration stage, CH4 production potential in Treatment CF was much higher than that in Treatment II, while CH4 oxidation potential in Treatment CF was lower than that in Treatment II. As a result, CH4 emission in Treatment CF was much higher than that in Treatment II （p 〈 0,05）. Mid-season aeration significantly reduced CH4 production potential, promoted CH4 oxidation potential, and eventually decreased CH4 emission from rice paddy soil （p 〈 0.05）. Water management affected CH4 emission from rice paddy soil by influencing CH4 production potential and CH4 oxidation potential.