Oo Aung Zaw, Win Khin Thuzar, Bellingrath-Kimura Sonoko Dorothea
Tokyo University of Agriculture and Technology, Graduate School of Agriculture, Department of International Environmental and Agricultural Science, Saiwaicho 3-5-8, Fuchu, Tokyo 183-8509 Japan.
Springerplus. 2015 Mar 26;4:145. doi: 10.1186/s40064-015-0901-2. eCollection 2015.
An assessment of within field spatial variations in grain yield and methane (CH4) emission was conducted in lowland rice fields of Myanmar. Two successive rice fields (1(st) field and 2(nd) field) were divided into fertilized and non-fertilized parts and CH4 measurements were conducted at the inlet, middle and outlet positions of each field. The results showed that CH4 emissions at non-fertilized parts were higher than those at fertilized part in both rice fields. The average CH4 emissions ranged from 8.7 to 26.6 mg m(-2) h(-1) in all positions in both rice fields. The spatial variation in CH4 emission among the positions was high in both rice fields with the highest emissions in the outlet of the 1(st) field and the inlet of the 2(nd) field. The CH4 emissions at these two positions showed 2 - 2.5 times higher than those at other positions in both rice fields. Stepwise regression analysis indicates that soil total carbon content is the primary factor for CH4 emission. The average CH4 emissions during rice growing season were 13.5 mg m(-2) h(-1) for the 1(st) field and 15.7 mg m(-2) h(-1) for the 2(nd) field. Spearman rank order correlation analysis showed that CH4 emission was significantly and positively correlated with soil temperature, surface water depth and negatively correlated with soil redox potential. The result indicated that high within field spatial variation in CH4 emissions required different site specific management practices to mitigate CH4 emissions in lowland paddy rice soil.
对缅甸低地稻田的粮食产量和甲烷（CH₄）排放的田间空间变化进行了评估。两块连续的稻田（第一块田和第二块田）被分为施肥区和未施肥区，并在每块田的进水口、中间和出水口位置进行了CH₄测量。结果表明，两块稻田中未施肥区的CH₄排放量均高于施肥区。两块稻田所有位置的CH₄平均排放量在8.7至26.6毫克·米⁻²·小时⁻¹之间。两块稻田中各位置间CH₄排放的空间变化都很大，第一块田的出水口和第二块田的进水口CH₄排放量最高。这两个位置的CH₄排放量比两块稻田中其他位置高出2至2.5倍。逐步回归分析表明，土壤总碳含量是CH₄排放的主要因素。第一块田水稻生长季的CH₄平均排放量为13.5毫克·米⁻²·小时⁻¹，第二块田为15.7毫克·米⁻²·小时⁻¹。Spearman秩相关分析表明，CH₄排放与土壤温度、地表水深度呈显著正相关，与土壤氧化还原电位呈负相关。结果表明，CH₄排放的田间高空间变化需要不同的因地制宜管理措施来减少低地稻田土壤中的CH₄排放。
