ABSTRACT

Soil fluxes of nitrous oxide (N₂O) play an important role in the global greenhouse gas budget. However, the response of soil N₂O emissions to climate change in temperate forest plantations is not yet well understood. In this study, we assessed the responses of soil N₂O fluxes to experimental warming with or without water addition, using a replicated in situ heating (~2°C above ambient) and water addition (170 mm) experiment in a temperate Sitka spruce plantation forest over the period 2014–2016. We found that seasonal fluxes of N₂O during the year were highly variable, ranging from net uptake to net emissions. Seasonal variations in soil N₂O fluxes were not correlated with either soil temperature or soil moisture. In addition, none of the individual warming/watering treatments, or their interactions, had significant effects on soil N₂O fluxes and N-related soil properties. Overall, our results suggest that despite future increases in temperature, soil N₂O emission may remain largely unchanged in many temperate forest ecosystems that are often N-limited.

摘要

一氧化二氮（N ₂ O）的土壤通量在全球温室气体预算中扮演重要角色。然而，温带森林人工林中土壤N ₂ O排放对气候变化的响应尚不十分清楚。在这项研究中，我们在温带锡特卡云杉中使用重复的原位加热（高于环境温度约2°C）和加水（170 mm）实验，评估了土壤N ₂ O通量对有或无加水的实验变暖的响应。2014-2016年期间的人工林。我们发现一年中N ₂ O的季节性通量变化很大，从净吸收到净排放不等。土壤N _2的季节性变化O通量与土壤温度或土壤湿度均无关。此外，单独的增温/浇水处理或它们之间的相互作用都没有对土壤N ₂ O通量和与N相关的土壤特性产生显着影响。总体而言，我们的结果表明，尽管未来温度会升高，但在许多通常受到氮限制的温带森林生态系统中，土壤N ₂ O的排放量可能基本保持不变。