西双版纳热带森林恢复对土壤反硝化N2O排放的影响OA北大核心CSTPCD

This study aimed to explore the effect of tropical forest restoration on the spatiotemporal dynam-ics of N2O emissions from soil denitrification.The continuous indoor-culture method(pure-oxygen inhibi-tion denitrification)and high-throughput metagenomic sequencing technology were used to determine the N2O emissions and microbial diversity in tropical forests(i.e.,Mallotus paniculatus,Mellettia leptobota,and Syzygium oblatum communities)at different restoration stages in Xishuangbanna.We also determined the linkage of denitrifying N2O emission with soil microbial diversity and chemical properties.The results showed that 1)tropical forest restoration significantly affected the N2O emissions from soil denitrification(P＜0.05).The average emission rates were ranked as S.oblatum(303.16±37.57)＞M.leptobota(251.38±28.37)＞M.paniculatus(193.45±26.76 μg·kg-1·h-1).2)N2O emission rates of denitrifica-tion had a significant spatio-temporal variation.They were significantly higher in the wet season(June and September)than in the dry season(March and December);the range of the fluctuations in N2 O emission rates from wet to dry season ranked as M.paniculatus(2.94 times)＞S.oblatum(2.50 times)＞M.leptob-ota(2.22 times);the vertical variation decreased along the soil profile.3)The explanatory order of soil wa-ter content,microbial biomass carbon and Shannon diversity for the changes of denitrifying N2O emissions at the three restoration stages was ranked as S.oblatum(68.77％,70.45％,and 97.87％)＞M.leptobota(62.54％,57.16％,and 96.8％)＞M.paniculatus(54.56％,46.46％,and 93.17％).4)The result of prin-cipal component analysis showed that total organic carbon,readily oxidizable carbon,Shannon index,water content,and microbial carbon were the main factors regulating the N2O emissions from denitrification.The contribution of total,nitrate,ammonium,and hydrolyzed nitrogen,Chao index,and Simpson index ranked the second.Tropical forest restoration can regulate the spatiotemporal variations in N2O emission during soil denitrification,probably through mediating denitrifying bacterial diversity,water content,and carbon pool components.