Effect of organizational paddy water management by a water user group on methane and nitrous oxide emissions and rice yield in the Red River Delta, Vietnam
Effect of organizational paddy water management by a water user group on methane and nitrous oxide emissions and rice yield in the Red River Delta, Vietnam
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DOI：
10.1016/j.agwat.2019.02.015
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发表时间：
2019-05-20
影响因子：
6.7
通讯作者：
Onishi, Takeo
中科院分区：
文献类型：
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作者：
Quang, Le Xuan;Nakamura, Kimihito;Onishi, Takeo
为了减少稻田温室气体排放，解决水资源短缺问题，迫切需要构建可持续的生态友好型水稻水资源管理系统。干湿交替（AWD）水管理是有效的，节约用水。然而，在地区或农场层面实施AWD的实例有限。我们的目的是调查AWD在越南红河三角洲地区约44公顷稻田的实验区块单元（常规、弱旱和强旱）中的可行性，方法是检查间歇灌溉（即，AWD）对积水深度、CH_4和N_2O排放以及水稻产量的影响。预计将通过该地区水管理组织（水用户组）操作灌溉泵和分水工程的闸门实现间歇灌溉。然而，由于研究区降雨频繁，积水深度下降速度慢，积水深度没有按照最初的计划进行控制。然而，它被证实，在此期间，积水深度下降到土壤表面以下的时间大多数（但不总是）在干型块更长。CH4排放量随着干燥期的增加而减少，这种减少在夏秋季节很大。N2O排放量与水管理之间似乎没有关系。水稻产量下降，由于极端干旱在夏秋季节，但不受干旱的冬春季节。这项研究表明，通过实现最大干燥指数（即，在目标区域的稻田中，在夏秋季节，积水深度在土壤表面以下的时间的比率）为0.6。
To mitigate the emissions of greenhouse gases from paddy fields and solve water shortage problems, sustainable and eco-friendly water management systems for rice cultivation urgently need to be constructed. Alternate wetting and drying (AWD) water management is effective and saves water. However, practical examples of AWD at the district or on-farm level are limited. We aimed to investigate the feasibility of AWD in experimental block units (conventional, weak-dry, and strong-dry) in paddy fields of about 44 ha in the Red River Delta area of Vietnam by examining the effects of intermittent irrigation (i.e., AWD) on the ponding depth, CH4 and N2O emissions, and rice yield in blocked experimental plots. Intermittent irrigation was expected to be achieved through the operation of irrigation pumps and sluice gates of water division works by the water management organization (water user group) of the district. However, the ponding depth was not controlled as initially planned because of frequent rainfall and low rate of decrease of the ponding depth in the study area. It was, however, confirmed that the period during which the ponding depth decreased below the soil surface was mostly (but not always) longer in the dry-type blocks. CH4 emissions decreased with an increase in drying period and this reduction was large in the summer-autumn season. There appeared to be no relationship between N2O emissions and water management. Rice yield decreased due to extreme drying in the summer-autumn season but was not affected by drying in the winter-spring season. This study demonstrated that CH4 emissions can be reduced and rice yield can be maintained by achieving a maximum drying index (i.e., ratio of the period during which the ponding depth is below the soil surface) of 0.6 in the summer-autumn season in the paddy fields of the target area.