土壤背景N2O排放对土地利用、土壤性质与气候参数的响应——基于全球的荟萃分析

Responses of soil background N2O emissions to land use, soil properties, and climate parameters based on a global Meta analysis

  • 摘要: 土壤背景N2O排放是指未施用氮肥或未采用土壤管理措施的土壤所排放的N2O。随着人为活动的增加, 土壤背景N2O排放逐年增加, 对环境和气候的影响日益显著。然而, 目前关于土壤背景N2O排放的主要控制因素和潜在机制尚不清楚。本文根据全球282项研究的土壤背景N2O排放的实地观测数据以及气候因子和土壤因子数据, 绘制了纳入本研究中的地点分布图。本研究涉及的站点广泛分布于全球六大洲, 涵盖了3种主要的土地利用类型, 包括耕地、林地和草地。研究发现, 全球土壤背景N2O排放范围为0.01~19.80 kg(N)∙hm−2∙a−1, 其平均值为1.68 kg(N)∙hm−2∙a−1。其中, 草地土壤背景N2O排放分布范围最广, 为0.03~19.80 kg(N)∙hm−2∙a−1, 耕地和林地土壤背景N2O排放分别为0.01~7.10和0.12~4.70 kg(N)∙hm−2∙a−1。进一步通过荟萃分析和多元线性逐步回归分析, 系统评估并深入研究了影响土壤背景N2O排放的多种因子, 包括土壤pH值、土壤容重、土壤总氮、年平均温度、平均年降水量之间的相关性。主要得到以下结果: 1)与气候因子相比, 土壤属性对土壤背景N2O排放的影响程度更大; 2)在全球范围内不同土地利用方式下的土壤背景N2O排放存在差异; 3)土壤pH值对耕地、林地和草地的背景N2O排放均有显著影响。本研究为可持续农业的发展和管理战略提供了一定的启示, 同时为减少温室气体排放、保护臭氧层和缓解气候变化提供了重要支持。

     

    Abstract: Soil background N2O emissions are the N2O released from the soil without nitrogen fertilizer application or soil management during the planting cycle. With increased human activities, the amount of background N2O emissions from soil has gradually increased, and its impact on the environment and climate is increasingly significant. However, the key driving factors and underlying mechanisms related to background N2O emissions from the soil remain unclear. The distribution of the 282 studies included in this research was mapped based on field observation data of soil background N2O emissions, as well as climate and soil factor data across the world, which were distributed across six continents and covered three predominant land use types, i.e., cropland, forestland, and grassland, to address this knowledge gap. The results showed that the global background N2O emissions ranged from 0.01 to 19.80 kg(N)∙hm−2∙a−1, with an average of 1.68 kg(N)∙hm−2∙a−1. Among them, the range of soil background N2O emissions in the grassland ecosystem was the widest, from 0.03 to 19.80 kg(N)∙hm−2∙a−1. The soil background N2O emissions in cropland and forestland ecosystems ranged from 0.01 to 7.10 kg(N)∙hm−2∙a−1 and from 0.12 to 4.70 kg(N)∙hm−2∙a−1, respectively. Furthermore, we conducted a systematic evaluation and in-depth investigation of various factors affecting soil background N2O emissions, including soil pH, soil bulk density, soil total nitrogen, mean annual temperature, and mean annual precipitation, as well as the relationships between soil properties and climatic parameters with soil background N2O emissions across different land use types. The main results were as follows: 1) compared with climatic factors, soil properties had a greater impact on soil background N2O emissions; 2) soil background N2O emissions under different land use types were different on a global scale; and 3) soil pH had significant effects on soil background N2O emissions in cropland, forestland, and grassland ecosystems. This study provides valuable insights into the development and management strategies of sustainable agriculture and offers a scientific basis for mitigating N2O emissions from the soil. It also provides critical support for reducing greenhouse gas emissions, protecting the ozone layer, and mitigating the impacts of climate change on ecosystems.

     

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