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.
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.
作者
杨灵芳
孔东彦
刁静文
郭鹏
YANG Ling-fang;KONG Dong-yan;DIAO Jing-wen;GUO Peng(College of Food and Biology,Hebei University of Science and Technology,Shijiazhuang 050018,China)
出处
《环境科学》
EI
CAS
CSCD
北大核心
2023年第11期6226-6234,共9页
Environmental Science
基金
河北省自然科学基金项目(C2020208001)
河北省人才培养工程项目(A201901041)。
