Soil samples were taken from depth of 0-12cm in the virgin broad- leaved/Korean pine mixed forest in Changbai Mountain in April, 2000. 20 μL·L-1 and 200 μL·L-1 CH4 and N2O concentration were supplied for a...Soil samples were taken from depth of 0-12cm in the virgin broad- leaved/Korean pine mixed forest in Changbai Mountain in April, 2000. 20 μL·L-1 and 200 μL·L-1 CH4 and N2O concentration were supplied for analysis. Laboratory study on CH4 oxidation and N2O emission in forest soil showed that fresh soil sample could oxidize atmospheric methane and product N2O. Air-dried soil sample could not oxidize atmospheric methane, but could produCt N2O. However, it could oxidize the supplied methane quickly when its concentration was higher than 20 μL·L-1. The oxidation rate of methane was increased with its initial concentration. An addition of water to dry soil caused large pulse of N2O emissions within 2 hours. There were curvilinear correlations between N2O emission and temperature (r2=0.706, p <0.05), and between N2O emission andtwater content (r2=0.2968. p <0.05). These suggested temperature and water content were important factors controlling N2O emission. The correlation between CH4 oxidization and temperature was also found while CH4 was supplied 200 μL·L-1 (r2 =0.3573, p<0.05). Temperature was an important f8Ctor controlling CH4 oxidation. However, when 20 μL·L-1 CH4 was supplied, there was no correlation among CH4 oxidization, N2O emission, temperature and water content.展开更多
Aims Forest disturbance from extreme weather events due to climate change could increase the contribution of fresh green leaves to the litter layer of soil and subsequently alter the composition and activity of the so...Aims Forest disturbance from extreme weather events due to climate change could increase the contribution of fresh green leaves to the litter layer of soil and subsequently alter the composition and activity of the soil microbial properties and soil carbon cycling.The objective of this study was to compare the effect of naturally fallen litter and fresh leaves on the soil microbial community composition and their activities.Methods Fresh leaves and normal fallen litter were collected from four tree species(Pinus elliottii,Schima superba,Acacia mangium,A.auriculaeformis)in subtropical China and mixed with soil.Soil microbial community composition was determined using PLFAs,and its activity was quantified by soil respiration.During a 12-month period,the decomposition rate of litter was measured bimonthly using a litterbag method.Soil microbial samples were collected after 6 and 12 months.Soil respiration was measured monthly.Important Findings We found that fresh leaves decomposed faster than their conspecific fallen litter.Although total microbial biomass and bacterial biomass were similar among treatments,soil fungal biomass was higher in fresh leaf than fallen litter treatments,resulting in greater values of the Fungal phospholipid fatty acids(PLFAs)/Bacterial PLFAs ratio.Fungal PLFA values were greater for Schima superba than the other species.The effect of litter type on soil respiration was species-dependent.Specifically,fallen litter released 35%more CO_(2) than fresh leaves of the conifer P.elliottii.The opposite pattern was observed in the broadleaf species whose fresh leaf treatments emitted 17%–32%more CO_(2) than fallen litter.Given future predictions that global climate change will cause more disturbances to forests,these results indicate that conifer and broadleaf forests in subtropical China may respond differently to increased fresh litter inputs,with net soil microbial respiration decreasing in conifer forests and increasing in broadleaf forests.展开更多
文摘Soil samples were taken from depth of 0-12cm in the virgin broad- leaved/Korean pine mixed forest in Changbai Mountain in April, 2000. 20 μL·L-1 and 200 μL·L-1 CH4 and N2O concentration were supplied for analysis. Laboratory study on CH4 oxidation and N2O emission in forest soil showed that fresh soil sample could oxidize atmospheric methane and product N2O. Air-dried soil sample could not oxidize atmospheric methane, but could produCt N2O. However, it could oxidize the supplied methane quickly when its concentration was higher than 20 μL·L-1. The oxidation rate of methane was increased with its initial concentration. An addition of water to dry soil caused large pulse of N2O emissions within 2 hours. There were curvilinear correlations between N2O emission and temperature (r2=0.706, p <0.05), and between N2O emission andtwater content (r2=0.2968. p <0.05). These suggested temperature and water content were important factors controlling N2O emission. The correlation between CH4 oxidization and temperature was also found while CH4 was supplied 200 μL·L-1 (r2 =0.3573, p<0.05). Temperature was an important f8Ctor controlling CH4 oxidation. However, when 20 μL·L-1 CH4 was supplied, there was no correlation among CH4 oxidization, N2O emission, temperature and water content.
基金National Natural Science Foundation of China(30870442)National Basic Research Program of China(2009CB421101 and 2011CB403200)+3 种基金NSFC-Guangdong Joint Project(U1131001)Guangdong Natural Science Foundation(S2011040005712)the Knowledge Innovation Program of the Chinese Academy of Sciences(KSCX2-EW-J-28)the‘Strategic Priority Research Program-Climate Change:Carbon Budget and Related Issues’of the Chinese Academy of Sciences(XDA05070307).
文摘Aims Forest disturbance from extreme weather events due to climate change could increase the contribution of fresh green leaves to the litter layer of soil and subsequently alter the composition and activity of the soil microbial properties and soil carbon cycling.The objective of this study was to compare the effect of naturally fallen litter and fresh leaves on the soil microbial community composition and their activities.Methods Fresh leaves and normal fallen litter were collected from four tree species(Pinus elliottii,Schima superba,Acacia mangium,A.auriculaeformis)in subtropical China and mixed with soil.Soil microbial community composition was determined using PLFAs,and its activity was quantified by soil respiration.During a 12-month period,the decomposition rate of litter was measured bimonthly using a litterbag method.Soil microbial samples were collected after 6 and 12 months.Soil respiration was measured monthly.Important Findings We found that fresh leaves decomposed faster than their conspecific fallen litter.Although total microbial biomass and bacterial biomass were similar among treatments,soil fungal biomass was higher in fresh leaf than fallen litter treatments,resulting in greater values of the Fungal phospholipid fatty acids(PLFAs)/Bacterial PLFAs ratio.Fungal PLFA values were greater for Schima superba than the other species.The effect of litter type on soil respiration was species-dependent.Specifically,fallen litter released 35%more CO_(2) than fresh leaves of the conifer P.elliottii.The opposite pattern was observed in the broadleaf species whose fresh leaf treatments emitted 17%–32%more CO_(2) than fallen litter.Given future predictions that global climate change will cause more disturbances to forests,these results indicate that conifer and broadleaf forests in subtropical China may respond differently to increased fresh litter inputs,with net soil microbial respiration decreasing in conifer forests and increasing in broadleaf forests.
