School of Ecology and Nature Conservation, Beijing Forestry University, Beijing, 100083, China; Qilaotu Mountain National Observation and Research Station of Chinese Forest Ecosystem, Chifeng, 024400, China.
J Environ Manage. 2022 Aug 15;316:115283. doi: 10.1016/j.jenvman.2022.115283. Epub 2022 May 21.
The carbon and nitrogen reserves of forest soil play a key role in combating global climate change. Afforestation is considered an effective measure for increasing carbon and nitrogen reserves in terrestrial forest ecosystems. However, the mechanisms governing how different developmental stages of plantations affect soil carbon and nitrogen stability and storage remain unclear. In this study, we selected three developmental stages of the Larix principis-rupprechtii plantations: medium mature forest (30 yr), near mature forest (40 yr) and mature forest (50 yr). We studied the distribution and stability of soil aggregates at distinct developmental stages, the distribution of carbon and nitrogen pools related to aggregates, and their relationship to environmental factors. We found that with increasing forest age, the soil sand particles became finer. In each developmental stage, the proportion of aggregates >0.25 mm reached more than 85%. The concentrations of carbon and nitrogen in the soil aggregates were lower in the near mature forest (40 a) than in the medium mature forest (30 a), but reached a maximum in the mature forest (50 a). There were significant positive correlations between soil carbon and nitrogen concentrations and soil relative water content (RWC), forest age, and stand density. Soil texture strongly affected the distribution of aggregates. TOC/TN was mainly influenced by aggregate distribution, which was most vulnerable to environmental factors. Environmental factors have a significant negative impact on soil texture, and the path coefficient was -0.812. Environmental factors indirectly affected the concentrations of soil carbon and nitrogen by influencing the distribution and stability of soil aggregates. Therefore, different developmental stages of plantations strongly affected forest carbon and nitrogen pools by changing the soil structure and environmental factors. This study provides a basis for understanding the mechanisms of forest soil carbon and nitrogen storage.
森林土壤的碳氮储量在应对全球气候变化方面起着关键作用。造林被认为是增加陆地森林生态系统碳氮储量的有效措施。然而，不同造林发育阶段如何影响土壤碳氮稳定性和储存的机制仍不清楚。本研究选择了落叶松人工林的三个发育阶段：中龄林（30 年）、近熟林（40 年）和成熟林（50 年）。研究了不同发育阶段土壤团聚体的分布和稳定性、与团聚体相关的碳氮库的分布及其与环境因子的关系。结果表明，随着林龄的增加，土壤砂粒变细。在每个发育阶段，>0.25mm 团聚体的比例均达到 85%以上。近熟林（40 年）土壤碳氮浓度低于中龄林（30 年），但在成熟林（50 年）达到最大值。土壤碳氮浓度与土壤相对含水量（RWC）、林龄和林分密度呈显著正相关。土壤质地强烈影响团聚体的分布。TOC/TN 主要受团聚体分布的影响，而团聚体对环境因子最为敏感。环境因子对土壤质地有显著的负面影响，路径系数为-0.812。环境因子通过影响土壤团聚体的分布和稳定性，间接影响土壤碳氮的浓度。因此，不同发育阶段的人工林通过改变土壤结构和环境因子强烈影响森林碳氮储量。本研究为了解森林土壤碳氮储存机制提供了依据。
