Effects of water management and cultivar on carbon dynamics, plant productivity and biomass allocation in European rice systems
Effects of water management and cultivar on carbon dynamics, plant productivity and biomass allocation in European rice systems
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DOI：
10.1016/j.scitotenv.2019.06.110
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发表时间：
2019-10
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通讯作者：
V. Oliver;N. Cochrane;Julia Magnusson;Erika Brachi;S. Monaco;A. Volante;B. Courtois;G. Valè;A. Price;Y. Teh
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文献类型：
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作者：
V. Oliver;N. Cochrane;Julia Magnusson;Erika Brachi;S. Monaco;A. Volante;B. Courtois;G. Valè;A. Price;Y. Teh
由于气候变化减缓和水资源使用日益短缺，干湿交替（AWD）等节水技术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 4）的排放;然而，这种净气候效益可能会被土壤中二氧化碳（CO2）排放量的增加所抵消。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，并建立潜在的机制基础上观察到的趋势，在意大利稻田的净生态系统C增益或损失。我们调查了传统水管理的效果（即传统水浸稻田; CF）和AWD对生物量积累的影响（地上、地下、谷物），关键生态系统碳通量（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）），和土壤有机质（SOM）腐烂的四个常见的商业欧洲水稻品种。最重要的发现是，无论是治疗还是品种影响NEE，GPP，ER或SOM分解。RA是CF和AWD治疗ER的主要贡献者。品种和处理影响了水稻植株的总生物量;具体而言，与AWD相比，CF中的根产量更大。重要的是，处理对任何栽培品种的总产量没有影响。可能是干湿循环不足以使土壤碳代谢充分，或者土壤中缺乏不稳定的基质。这些结果表明，AWD系统可能不会增加土壤碳流失的风险，使其成为减缓气候变化和保护水资源的可行解决方案。虽然还需要更多的研究，但AWD在欧洲的初步前景是积极的; SOM分解不会造成土壤碳的净损失，同时也能保持产量。
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 (CH4) emissions; however, this net climate benefit may be offset by enhanced carbon dioxide (CO2) 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.