有机肥施用对设施菜地土壤氮氧化物排放影响的底物效应与微生物学机制

In China, greenhouse soil is the considerable emission source of NO and NO2, and partial replacement of inorganic fertilizer by organic fertilizer (OF) is an important strategy and inexorable trend for ensuring the sustainable development of greenhouse vegetable production. Currently, limited studies have been focused on evaluating the effects of OF application on soil NOx emissions in greenhouse soil, especially the involved mechanisms still remain unclear. On this background, this study will assess the influence of application of different OFs on soil NOx emissions in greenhouse soil, thus evaluating the environmental effects. In addition, microcosm incubation experiment will also be included for exploring the involved mechanism, as for (i) investigating the substrates effects with regard to the influence of different organic substrates and microbes on soil nitrogen cycle and NOx emissions; and (ii) studying the microbial mechanisms involved in the NOx emissions affected by OF application, including both the direct effects brought by endogenous microbes in OF, and additive functional microbes, and indirect effects caused by shift of indigenous microbial community and function. The results of this study will offer data support for assessment of the effects of OF application on NOx emissions in greenhouse soil, and help to elucidation of the involved action mechanisms, as well as providing theoretical basis for reasonable application of OF.

设施菜地是我国氮氧化物的重要排放源；同时，有机（类）肥料部分替代化肥已成为保障设施菜地种植业健康发展的重要途径和必然趋势。目前有关有机肥施用对设施菜地土壤氮氧化物排放影响的观测评估还较为匮乏，特别是相关的作用机制尚不明确。在此背景下，本项目拟通过田间试验观测评估不同种类有机肥施用对设施菜地氮氧化物排放的影响，评价其环境效应；同时结合室内培养试验试图阐明其中的作用机理，一方面探究不同有机肥物料的理化特征和微生物影响土壤氮素循环与氮氧化物排放的底物效应，另一方面揭示有机肥中内源微生物和外源功能菌直接影响或通过调控土壤本底微生物区系而影响氮氧化物排放的微生物学机制。预期本项目研究结果不仅为合理评估设施菜地施用有机（类）肥料对氮氧化物排放等环境效应提供数据支撑，同时有助于明确相关的作用机理，并为指导有机肥料的合理施用提供理论依据。

设施菜地是我国氮氧化物的重要排放源。有机（类）肥料部分替代化肥已成为保障设施菜地种植业健康发展的重要途径和必然趋势。本研究通过开展田间原位观测试验，采用静态暗箱-气相色谱/氮氧化物分析法同步观测N2O和NO排放通量，评估了有机类肥料（普通有机肥、添加木霉菌生物有机肥和灭菌有机肥）替代化肥施用对设施菜地土壤季节和年际N2O和NO排放强度及排放系数的影响。通过荧光定量PCR，定量分析了N2O和NO排放相关功能基因丰度对有机类肥料施用的响应，并通过高通量测序方法，分析有机类肥料施用对其相关功能基因群落组成的影响，明确有机类肥料施用对土壤氮氧化物排放及相关功能微生物影响的底物效应，揭示设施菜地土壤氮氧化物排放及其关联微生物学机制。研究结果表明，与单独施用化肥相比，有机类肥料的施用显著减少了土壤N2O和NO排放量，减排效率分别为18.2−32.3%和62.4−73.3%。有机类肥料替代化肥的施用抑制了设施菜地土壤硝化作用并促进了反硝化过程中N2O的还原，显著降低了土壤N2O和NO排放。此外有机类肥料施用有利于土壤质量和土壤生物多样性的保持，但可能会降低作物产量。本研究中木霉菌富集生物有机肥的施用，可以提高蔬菜产量，并降低单位产量N2O和NO排放。因此，生物有机肥的使用可能是减少设施菜地种植系统中氮素损失并保证作物产量的一种有前景的施肥策略。