Tea plantations are an important N2O source. Fertilizer-induced N2O emission factors of tea plantations are much higher than other upland agricultural ecosystems. According to the basic information on characteristics and knowledge of N2O emissions from tea plantations around the world, we comprehensively reviewed N2O emission characteristics, production process, influencing factors, and reduction measures from tea plantations. The global means of ambient N2O emission and N2O emission stimulated by nitrogen fertilizer application from tea plantations were (2.68±2.92) kg N·hm-2 and (11.29±9.45) kg N·hm-2, respectively. The fertilizer-induced N2O emission factor in tea plantations (2.2%±2.1%) was much higher than the IPCC-estimated N2O emission factor for agricultural land (1%). N2O emission from tea plantation soil (a typical acid soil) were mainly produced during nitrification and denitrification, with denitrification being dominant. N2O emission from tea plantations were significantly related to the amount of fertilizer application. Other factors, such as fertilizer type, could also affect soil N2O emissions in tea plantations. The main reduction methods of N2O emission from tea plantations included optimizing the amount and type of fertilizer, amending biochar, and rationally using nitrification inhibitors. In future, we should strengthen in-situ observations of soil N2O emission from tea plantations at both temporal and spatial scales, combine lab incubation and field studies to elucidate the mechanisms underling tea plantation soil N2O emissions, and use a data-model fusion approach to reduce uncertainties in the estimation of global N2O emission. These would provide theoretical support and practical guidance for reasonable N2O emission reduction in tea plantations.
茶园土壤是温室气体氧化亚氮(N2O)排放的重要来源,且茶园土壤中施肥诱导的N2O排放系数远大于旱地农田。针对全球茶园的特点和N2O排放研究现状,本文综合分析了茶园N2O排放特征、产生过程、影响因素及减排措施。全球茶园土壤N2O背景排放量平均为(2.68±2.92) kg N·hm-2,氮肥施用后N2O平均排放量为(11.29±9.45) kg N·hm-2。化肥诱导的N2O排放系数为2.2%±2.1%,远高于IPCC估算的农田N2O排放系数(1%)。茶园土壤是典型的酸性土壤,N2O产生主要包括硝化和反硝化过程,其中反硝化作用占主导。茶园土壤N2O排放主要与施肥量有关,此外,施肥种类也影响茶园土壤N2O排放。茶园土壤N2O减排途径主要包括优化施肥量和施肥种类、添加生物炭以及合理利用硝化抑制剂等。今后应加强时间和空间尺度上茶园土壤N2O排放的原位观测,结合实验室培养和野外试验阐明茶园土壤N2O产生和排放机制,利用数据-模型融合方式减少全球茶园N2O排放估算的不确定性,为合理的茶园N2O减排措施提供理论支撑和实践指导。.
Keywords: N2O emission; emission factor; fertilizer application rate; reduction measure; tea plantation.