Alteration of nitrous oxide emissions from floodplain soils by aggregate size, litter accumulation and plant–soil interactions

Semi-terrestrial soils such as floodplain soils are considered potential hot spots of nitrous oxide (N2O) emissions. Microhabitats in the soil – such as within and outside of aggregates, in the detritusphere, and/or in the rhizosphere – are considered to promote and preserve specific redox conditions. Yet our understanding of the relative effects of such microhabitats and their interactions on N2O production and consumption in soils is still incomplete. Therefore, we assessed the effect of aggregate size, buried leaf litter, and plant–soil interactions on the occurrence of enhanced N2O emissions under simulated flooding/drying conditions in a mesocosm experiment. We used two model soils with equivalent structure and texture, comprising macroaggregates (4000–250 µm) or microaggregates (<250 µm) from a N-rich floodplain soil. These model soils were planted with basket willow (Salix viminalis L.), mixed with leaf litter or left unamended. After 48 h of flooding, a period of enhanced N2O...

泛陆生土壤（如河漫滩土壤）被视为一氧化二氮（N₂O）排放的潜在热点区域。土壤中的微生境——例如团聚体（aggregates）内部与外部、碎屑圈（detritusphere）以及根际（rhizosphere）——被认为可促进并维持特定的氧化还原条件。然而，当前学界对这类微生境的相对效应及其相互作用如何调控土壤中N₂O的产生与消耗的认知仍不完善。因此，本研究借助中宇宙（mesocosm）实验，在模拟干湿交替条件下，评估了团聚体粒径、埋藏落叶以及植物-土壤相互作用对N₂O排放增强现象的影响。本研究采用两种结构与质地一致的模式土壤，分别由取自富氮河漫滩土壤的大团聚体（macroaggregates，4000~250 μm）与微团聚体（microaggregates，<250 μm）构成。将上述模式土壤分别开展三种处理：种植篮柳（Salix viminalis L.）、混入落叶，或不做任何额外添加处理。在水淹48小时后，一段N₂O排放增强的时段……