摘要
土壤氮素总转化速率及其相对强弱决定了土壤保氮、供氮能力。分析森林土壤氮素总转化速率调控因素,对于了解森林生态系统的生产力、氮素循环及环境变化有重要的意义。本文利用随机森林模型分析了全球范围内36篇关于森林土壤氮转化的文献,结果发现,影响森林土壤氮素总矿化速率的关键因素为:全氮>砂粒含量>年均温>凋萎系数;影响森林土壤总硝化速率的关键因素为:全氮>全碳>砂粒含量>阳离子交换量;影响森林土壤硝酸盐异化还原为铵(DNRA)速率的关键因素为:黏粒含量>土壤有效含水量>凋萎系数>阳离子交换量。据此,建立了全球森林土壤氮素总转化速率随机森林模型,并给出了全球尺度森林土壤总矿化速率、总硝化速率和DNRA速率的空间分布。结果发现,氮素总矿化速率的变化范围为1.672～64.016 mg N·kg^(-1)·d^(-1);总硝化速率的变化范围为0.866～16.984 mg N·kg^(-1)·d^(-1);DNRA速率的变化范围为0.030～2.045 mg N·kg^(-1)·d^(-1)。土壤氮素总转化速率具有较大的空间异质性,具体表现在:全球大部分地区3种转化速率水平均很低;而最大转化速率的空间分布有重叠,出现在北美洲西北部地区、欧洲西北部地区以及欧亚大陆连接处地区。
The total transformation rate of soil N and its relative strength determine N conserva- tion and supply capacity of soils.Studies on the controlling factors of total N transformation rate of forest soils have great significance for understanding productivity,N cycling and environmental change of forest ecosystems.Here we conducted random forest model analysis upon 36literatures of forest soil gross N transformation.We found that critical factors influencing the gross N minerali- zation rate were in order of TN>SNDPPT>MAT>WWP,the critical factors influencing the gross nitration rate were in order of TN>TC>SNDPPT>CEC,and the critical factors influencing the dissimilatory nitrate reduction to ammonium (DNRA)rate were in order of CLY>AWC>WWP> CEC.Then,a random forest model of total N transformation rate in forest soils was constructed and the spatial distribution of gross soil N mineralization rate,gross nitrification rate and DNRA rate were delivered.The results showed that the gross N mineralization rate ranged 1.672-64.016 mg N·kg^-1 ·d^-1,the gross nitration rate was 0.866-16.984mg N·kg^-1·d^-1,and the DNRA rate was 0.030-2.045mg N ·kg^-1·d^-1.The gross transformation rate of soil N had substantial spatial heterogeneity.Specifically,these three transformation rates were very low in most parts of the world,and the spatial distribution of the maximum transformation rates overlapped in north- western North America,northwestern Europe,and the Eurasian Continental junction.
作者
赵婷
张军辉
王芳
耿世聪
ZHAO Ting;ZHANG Jun-hui;WANG Fang;GENG Shi-cong(Key Laboratory of Forest Ecology and Management,Institute of Applied Ecology,Chinese Academy of Sciences,Shenyang 110016,China;University of Chinese Academy of Sciences,Beijing 100049,China)
出处
《生态学杂志》
CAS
CSCD
北大核心
2018年第12期3746-3756,共11页
Chinese Journal of Ecology
基金
国家自然科学基金项目(41430639和41675150)资助.
关键词
氮素总矿化速率
总硝化速率
DNRA速率
随机森林
空间分布
gross N mineralization rate
gross nitrification rate
DNRA rate
random forest
spatial distribution
