茶园土壤N2O排放特征及其关键调控因子

Nitrous oxide (N2O) is an important greenhouse gas, and agricultural soils are the main anthropogenic source of N2O to the atmosphere. Characteristics of tea field soil with largely amounts of manure were applied and special chemical and biological properties. The cultivation of tea with its high manure requirements creates and special chemical and biological properties potentially favorable conditions for high N2O emission. The aim of this study was to evaluate the tea field soils N2O emission characteristics and influence mechanism of N2O emissions. Therefore, the field and laboratory incubation experiments were carried out from the tea field soil, and with field measurements using static chamber/gas chromatography system. The overall objectives of this study are as: ⅰ) to examine the effect of different reclamation years on soil dissolved organic carbon, pH and N2O emission, and the impacts on N2O emission, ⅱ) to better understand the reaction mechanism of fertilizer application to simulate N2O emission in tea field soil, ⅲ) to show the relationship of N2O emission and soil microbial activity, ⅳ) to investigate the tea field soil N2O produce mechanism and its key driving factors. In addition, with this campaign study, we can enhance the research contents on soil-atmosphere exchange of greenhouse gases, intensify improve the database for N2O emissions from agricultural activities, and to provide theoretical basis and scientific guidance for agricultural greenhouse gas emission reduction strategies.

氧化亚氮（N2O）是一种重要的温室气体，农业土壤是其主要排放源。茶园土壤不仅存在有机肥输入过高的特点，还具有特殊的土壤生物化学环境，使其具备N2O较高排放的潜力。为了掌握茶园土壤N2O排放过程，本项目采取田间定位观测和室内培养的方法，采用静态箱-气相色谱采样分析技术，系统研究红壤区茶园土壤N2O排放特征及影响机制。分析不同种植年限对土壤可溶性有机碳（DOC）、pH值与N2O排放及其相互关系的影响；阐明N2O排放对肥料施用的响应机制；揭示N2O排放与土壤微生物活性的关系；探讨茶园土壤N2O产生机制及关键驱动因素。通过本项目研究，可以丰富土壤温室气体研究内容，进一步完善农业N2O排放清单，为我国农业温室气体减排措施提供理论依据和科学指导。

氧化亚氮（N2O）是一种重要的温室气体，农业土壤是其主要排放源。茶园土壤不仅存在有机肥输入过高的特点，还具有特殊的土壤生物化学环境，使其具备N2O较高排放的潜力。为了掌握茶园土壤N2O排放过程，本项目以湖北咸宁地区的茶园为研究对象，采取田间定位观测和室内培养的方法，系统研究了红壤区茶园土壤N2O排放特征及其影响因子。研究表明，植茶年限较短的茶园，其pH值高于植茶年限较长的茶园，土壤N2O累积排放量较高，林地土壤N2O累积排放量最低；茶园土壤N2O排放呈明显的季节变化，春夏季土壤N2O排放显著高于秋冬季；茶园土壤N2O排放的主要因子为土壤水分含量和硝态氮含量；植物残体碳氮的输入可显著促进茶园土壤N2O的排放，不同植物残体处理之间N2O排放量存在显著差异，与所施用的植物残体C:N比呈极显著的对数负相关关系，低C:N比处理具有较高的微生物生物量碳和可溶性有机碳含量，从而更有利于N2O较高排放；生物质炭降低了茶园土壤中的铵态氮含量，却提高了土壤pH值，从而显著降低了N2O排放通量。相对于作物秸秆而言，生物质炭提高了茶园土壤pH值，却降低了土壤N2O排放，因此生物质炭施用在减缓茶园土壤酸化及降低N2O排放等方面更具有积极意义。