Institute of Biological Sciences, University of Aberdeen, Cruickshank Building, St. Machar Drive, AB24 3UU Aberdeen, UK.
Institute of Biological Sciences, University of Aberdeen, Cruickshank Building, St. Machar Drive, AB24 3UU Aberdeen, UK.
Sci Total Environ. 2019 Oct 1;685:1139-1151. doi: 10.1016/j.scitotenv.2019.06.110. Epub 2019 Jun 8.
Water saving techniques, such as alternate wetting and drying (AWD), are becoming a necessity in modern rice farming because of climate change mitigation and growing water use scarcity. Reducing water can vastly reduce methane (CH) emissions; however, this net climate benefit may be offset by enhanced carbon dioxide (CO) emissions from soil. The main aims of this study were: to determine the effects of AWD on yield and ecosystem C dynamics, and to establish the underlying mechanistic basis for observed trends in net ecosystem C gain or loss in an Italian rice paddy. We investigated the effects of conventional water management (i.e. conventionally flooded paddy; CF) and AWD on biomass accumulation (aboveground, belowground, grain), key ecosystem C fluxes (net ecosystem exchange (NEE), net primary productivity (NPP), gross primary productivity (GPP), ecosystem respiration (ER), autotrophic respiration (RA), heterotrophic respiration (RH)), and soil organic matter (SOM) decay for four common commercial European rice cultivars. The most significant finding was that neither treatment nor cultivar affected NEE, GPP, ER or SOM decomposition. RA was the dominant contributor to ER for both CF and AWD treatments. Cultivar and treatment affected the total biomass of the rice plants; specifically, with greater root production in CF compared to AWD. Importantly, there was no effect of treatment on the overall yield for any cultivar. Possibly, the wetting-drying cycles may have been insufficient to allow substantial soil C metabolism or there was a lack of labile substrate in the soil. These results imply that AWD systems may not be at risk of enhancing soil C loss, making it a viable solution for climate change mitigation and water conservation. Although more studies are needed, the initial outlook for AWD in Europe is positive; with no net loss of soil C from SOM decomposition, whilst also maintaining yield.
节水技术，如交替湿润和干燥（AWD），由于气候变化缓解和日益严重的水资源短缺，正在成为现代水稻种植的必要条件。减少用水可以大大减少甲烷（CH）排放；然而，这种净气候效益可能会被土壤中增强的二氧化碳（CO）排放所抵消。本研究的主要目的是：确定 AWD 对产量和生态系统 C 动态的影响，并确定意大利稻田中观察到的净生态系统 C 增益或损失趋势的潜在机制基础。我们研究了常规水管理（即常规淹水稻田；CF）和 AWD 对生物量积累（地上、地下、谷物）、关键生态系统 C 通量（净生态系统交换（NEE）、净初级生产力（NPP）、总初级生产力（GPP）、生态系统呼吸（ER）、自养呼吸（RA）、异养呼吸（RH））和土壤有机物质（SOM）分解的影响对于四种常见的欧洲商业水稻品种。最显著的发现是，处理和品种都没有影响 NEE、GPP、ER 或 SOM 分解。RA 是 CF 和 AWD 处理中 ER 的主要贡献者。品种和处理影响水稻植株的总生物量；具体来说，CF 中根的产生比 AWD 更多。重要的是，对于任何品种，处理都没有对整体产量产生影响。可能是湿-干循环不足以允许大量土壤 C 代谢，或者土壤中缺乏易分解的基质。这些结果表明，AWD 系统可能不会增加土壤 C 损失的风险，因此是应对气候变化和节约用水的可行解决方案。尽管还需要更多的研究，但 AWD 在欧洲的初步前景是积极的；由于 SOM 分解没有净土壤 C 损失，同时也保持了产量。
