摘要
Aims It has been well recognized that understory vegetation plays an important role in driving forest ecosystem processes and functioning.In subtropical plantation forests,understory removal and fertiliza-tion have been widely applied;however,our understanding on how understory removal affects soil respiration and how the process is regulated by fertilization is limited.Here,we conducted an under-story removal experiment combined with fertilization to evaluate the effects of the two forest management practices and their inter-actions on soil respiration in subtropical forest in southern China.Methods The study was conducted in a split-plot design with fertilization as the whole-plot factor,understory removal as the subplot factor and block as the random factor in subtropical Eucalyptus plantations.In total,there were four treatments:control with unfertilized and intact understory(CK),understory removal but without fertilization(UR),with fertilization but without understory removal(FT)and with fertilization+understory removal(FT+UR).Eucalyptus above-and belowground biomass increment,fine root biomass,soil tempera-ture,soil moisture and soil respiration were measured in the present study.understory respiration(Ru)was quantified in different ways:Ru=RCK−Ru or Ru=RFT−R(FT+u);fertilization increased soil respiration(RFI)was also quantified in different ways:RFI=RFT−RCK or RFI=R(FT+u)−Ru.Important Findingsover a 2-year experiment,our data indicate that understory removal significantly decreased soil respiration,while fertilization increased soil respiration.understory removal decreased soil respiration by 28.8%under fertilization,but only 15.2%without fertilization.Fertilization significantly increased soil respiration by 23.6%with the presence of understory vegetation,and only increased by 3.7%when understory was removed,indicating that fertilization increased soil respiration mainly by increasing the contribution of the understory.our study advances our understanding of the interactive effects of understory m
基金
National Science Foundation of China(31210103920,30925010,31100384)
Strategic Priority Research of the Chinese Academy of Sciences(XDA05070301).
