| 氮沉降对陆地生态系统土壤有机碳含量影响的Meta分析 |
| 摘要点击 1464 全文点击 417 投稿时间：2022-11-11 修订日期：2023-01-14 |
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| 中文关键词 氮沉降 土壤有机碳(SOC) 年均温(MAT) 年均降水量(MAP) 土壤C:N 土壤pH 生态系统 |
| 英文关键词 nitrogen deposition soil organic carbon(SOC) mean annual temperature(MAT) mean annual precipitation(MAP) soil C:N soil pH ecosystem |
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| 中文摘要 |
| 研究已证实大气氮沉降的增加显著影响了土壤有机碳的含量，然而其变化幅度在不同的实验样地具有较大的差异.基于在我国开展的49个模拟氮沉降野外实验的408组数据，利用Meta分析、Meta回归和线性回归等方法系统研究了样地气候、土壤属性以及氮素施用参数对施氮后土壤有机碳含量的影响.结果表明，样地的年均温（MAT）和年均降水量（MAP）与施氮后土壤有机碳含量变化幅度显著正相关（P<0.05）.在MAT或MAP较低（MAT<3℃，MAP<500 mm）的样地中，施氮后土壤有机碳含量显著下降；而在MAT或MAP较高（MAT>3℃，MAP>500 mm）的样地中，施氮后土壤有机碳含量则显著升高.土壤属性方面，在C：N较高（>15）或酸性（pH<6.5）土壤中，施氮后土壤有机碳积累明显（P<0.05）；而在C：N较低（≤15）以及中性或碱性（pH≥6.5）土壤中，施氮后土壤有机碳变化不明显（P >0.05）.此外，施氮后草原生态系统土壤有机碳含量明显下降（-5.34%）；而湿地生态系统土壤有机碳含量变化不明显；森林生态系统土壤有机碳表现出明显积累（10.52%），特别是阔叶林生态系统（13.10%）.所有的因子中，土壤C：N是影响施氮后土壤有机碳变化幅度的主导因子.在施氮类型方面，施加硝酸铵或尿素后土壤有机碳含量显著升高，而施加硝态氮对其影响不显著.综上所述，在精确评估、预测和分析氮沉降对土壤有机碳含量的影响时，应综合考虑样地的气候、土壤属性以及氮素施用参数等因素对实验结果的影响. |
| 英文摘要 |
| Several studies have demonstrated that the increased deposition of nitrogen(N) has significantly affected the content of soil organic carbon(SOC); however, the change significantly varies in different regions. In this study, Meta-analysis, Meta-regression, and linear regression were performed to systematically evaluate the effects of climate, soil properties, and field design factors on the responses of SOC to N addition based on 408 data points from 49 field experiments in China. The results revealed that the response of SOC to N addition was significantly positively correlated with the mean annual temperature(MAT) and mean annual precipitation(MAP) of the sample sites(P<0.05). In the regions with lower MAT(<3℃) or MAP(<500 mm), SOC significantly decreased after N addition. In the areas with higher MAT(>3℃) or MAP(>500 mm); however, SOC significantly increased. For soil properties, SOC significantly accumulated after N addition in the plots with a higher soil C:N ratio(>15) or acidic soil(pH<6.5) but less changed in the plots with a lower C:N ratio(≤ 15) or higher pH(≥ 6.5). For ecotype, after N addition, SOC decreased significantly in the grassland ecosystem(-5.34%) but less changed in the wetland ecosystem. SOC accumulated the most after N addition in the forest ecosystem(10.52%), particularly in the broad-leaved forest ecosystem(13.10%). Further analysis showed that the soil C:N ratio was the most important factor. For type of N application, the addition of ammonium nitrate or urea increased the SOC content significantly, but the effect of nitrate was not significant. In summary, when accurately evaluating, predicting, and analyzing the effects of N addition on SOC content, the effects of climatic characteristics and soil properties of sample sites and field design factors should be comprehensively considered. |
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