Diel and Seasonal Variations of Methane Flux from Bang Khen Paddy Field in Thailand
Diel and Seasonal Variations of Methane Flux from Bang Khen Paddy Field in Thailand
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泰国Bang Khen稻田甲烷通量的昼夜和季节变化
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发表时间：
1999
期刊：
影响因子：
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通讯作者：
W. Cholitkul
中科院分区：
文献类型：
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作者：
K. Katoh;P. Chairoj;K. Yagi;H. Tsuruta;K. MlNAMI;W. Cholitkul
在泰国邦肯水稻试验站测定了稻田CH4通量的日变化和季节变化。抽穗期的Diel测定结果表明，水稻抽穗期的日平均通量为24.2 mg m·hr·1，与上午晚一些时的通量相当。1992年主稻、1993年次稻和1994年次稻CH4通量的季节变化平均值为21。7、4.3和6。7 mg m·h·1 *。第二稻的季节测量结果显示CH4排放量相对较低，这是由于旱季灌溉水量的限制导致水体深度很浅。结果表明，供水是影响全球稻田CH4排放速率的重要因素。附加关键词:全球变暖,甲烷通量、灌溉、水稻土 ----------------------------~------------------------------------------------·~~~ * 旱季雨季水稻种植和水稻种植hereadter被称为“主要大米”和“第二大米”,分别。69•)现在地址：国立农业生物资源研究所（筑波关农台，305-8602日本）现在地址：日本国际农业科学研究中心（QIRCAS）（筑波大和市，305-8686日本）现在地址：国立农业环境科学研究所（NIAES）（筑波关农台，305-8604日本）70 JIRCAS]。1999年7号引种至水稻植株成熟期。稻田淹水是CH4通量的主要变化源，是大气CH/的主要来源。为了准确估计泰国CH4通量的日变化，在1993年11月2-3日启动合作研究项目期间，NIAES-DOA在首阶段测量了CH4通量。测量是在1991年。Yagi等人)报道了泰国中部平原稻田在7:00、9:00、11:00、13:00、15:00、17:00进行的水稻CH4通量测定；19:00、21:00和23:00 h.素潘武里、Khlong Luang和Chai Nat。Khlong Luang和Chai Nat农田CH4排放量低的原因是土壤中硫酸盐浓度高，或者土壤的还原能力相对于氧化能力较低，土壤Eh较高。他们通过将上午和下午的平均通量乘以两倍来估计季节排放率。在大多数其他研究中，CH4排放率是使用白天测量的数据计算的，没有考虑通量的明显日变化。然而，考虑到CH4通量的日平均值，应采用CH4通量的日平均值来估算CH4的季节排放率。随后，1993年开始了JIRCAS-DOA的合作研究。本文试图评价水分状况和土壤温度对泰国邦肯稻田甲烷排放率的影响。材料与方法1)试验地点于1992年（主要水稻）和1993-1994年（次要水稻）在泰国中部平原的Bang Khen水稻试验站进行了田间测量。该遗址位于湄南河下游，土壤由最近的微咸冲积物形成。土壤性质见表1。这些性质的分析方法已在前一篇文章中描述过。在水稻移栽前对稻田进行灌溉，使地表水保持在0 ~ 20深度。3)CH4通量的季节变化。在前一季作物收获后，水稻植株的根和大约一半的地上生物量被纳入稻田。基肥用量为37.537.5 ~ 37.5 kg N- p20 5-K20 hm -1，追施尿素37.5 kg N- ha·。水稻（Oryza sativa）， J aponicaIndica杂交品种，按常规方法栽培。淹水、插秧、排水、收获、淹水期、所用水稻品种及水稻产量载于表2。在1992年种植主要水稻、1993年和1994年种植第二水稻期间，分别进行了4次、4次和9次测量。表1。水稻土系列邦肯（Bn）分类的若干性质
Diel and seasonal variations of CH4 flux from a paddy field were measured at Bang Khen Rice Experimental Station in Thailand. Diel measurement at the heading stage of rice plants showed that the daily average flux, amounting to 24.2 mg m· hr·1, was equivalent to the flux measured in the late morning. The average values of seasonal variations of CH4 fluxes in 1992 major rice, 1993 second rice and 1994 second rice were 21. 7, 4.3, and 6. 7 mg m· h·1, respectively*. The seasonal measurements in the second rice showed a relatively low CH4 emission, due to the very shallow water depth because of the limitation of the amount of irrigation water in the dry season. The results suggest that water supply is an important factor the evaluation of the global emission rates of CH4 from rice paddy fields. Additional key words: global warming, methane flux, irrigation, paddy soil ----------------------------~------------------------------------------------·~~~ *Wet season rice cropping and dry season rice cropping are hereadter referred to as "major rice"and "second rice", respectively. 69 •)Present address : National Institute of Agrobiological Resources (Kannondai, Tsukuba, 305-8602 Japan) cJPresent address: Japan International Research Center for Agricultural Sciences QIRCAS) (Ohwashi, Tsukuba, 305-8686 Japan) eJPresent address : National Institute of Agro-Environmental Sciences (NIAES) (Kannondai, Tsukuba, 305-8604 Japan) 70 JIRCAS ]. No. 7, 1999 Introduction cm until the maturation stage of rice plants. Flooded rice fields have been identified as a 2) Diel variation of CH4 flux major source of atmospheric CH/. To estimate The diel variations of the CH4 flux were accurately the CH4 flux in Thailand, NIAES-DOA measured at the heading stage during the period collaborative research program was initiated in November 2-3 1993. Measurements were 1991. Yagi et al. ) reported CH4 flux from rice performed at 7:00, 9:00, 11:00, 13:00, 15:00, 17:00, paddy fields in the central plain of Thailand ; 19:00, 21:00 and 23:00 h. Suphan Buri, Khlong Luang and Chai Nat. The low emission of CH4 from the Khlong Luang and Chai Nat fields was attributed to the high concentration of sulfate in soil or high soil Eh due to the lower reducing capacity in relation to the oxidizing capacity of soil. They estimated the seasonal emission rates by multiplying the averaged flux in duplicate both in the morning and in the afternoon. In most of the other studies the CH4 emission rates were calculated using the data measured during daytime, without considering the pronounced diel variation of the flux. However, daily average values of CH4 flux should be used to estimate the seasonal emission rates of CH4, in considering the diel pattern of the flux. Subsequently, JIRCAS-DOA collaborative research was initiated in 1993. In this paper attempts were made to evaluate the effect of the water regime and soil temperature on the methane emission rates from a paddy field in Bang Khen, Thailand. Materials and Methods 1) Experimental site Field measurements were performed at the Bang Khen Rice Experimental Station in the central plain of Thailand in 1992 (major rice) and 1993-1994 (second rice). This site is located in the lower reaches of the Chao Phraya River and the soil was formed from recent brackish alluvium. Soil properties were shown in Table 1. Methods of analysis of these properties were described in a previous paperl. Paddy field was irrigated prior to the transplanting of rice plants and surface water was maintained at depth ranging between O and 20 3) Seasonal variation of CH4 flux After the harvest of the previous crop, the roots and approximately half of the above groundbiomass of rice plants were incorporated into the paddy field. Chemical fertilizer at the rate of 37.537.5-37.5 kg N-P20 5-K20 ha-1 was applied as basal fertilizer and 37.5 kg N ha· of urea was top dressed. Rice plants (Oryza sativa), J aponicaIndica hybrid type, were cultivated according to the conventional method. Dates of flooding, transplanting, drainage, harvest, duration of the flooding period, rice varieties used and rice yield are given in Table 2. Four, four, and nine measurements were performed during the cultivation period of the major rice in 1992, the second rice in 1993 and 1994, respectively. Table 1. Some properties of the paddy soil Series Bang Khen (Bn) Taxonomy Typic Tropaquepts