Effects of acetylene at low concentrations on nitrification, mineralization and microbial biomass nitrogen concentrations in forest soils  

作　　者：ZHANG TengYu XU XingKai LUO XianBao HAN Lin WANG YingHong PAN GenXing 

机构地区：[1]State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China [2]Institute of Resource, Ecosystem and Environment of Agriculture, Nanjing Agricultural University, Nanjing 210095, China [3]Graduate University of Chinese Academy of Sciences, Beijing 100049, China

出　　处：《Chinese Science Bulletin》2009年第2期296-303,共8页

基　　金：Supported jointly by National Natural Science Foundation of China (Grant Nos. 20777071 and 20477044);Hundred Talents Project of the Chinese Academy of Sciences

摘　　要：Temperate forest surface soils at the varying distances from main trunks (e.g., Pinus koraiensis and Quercus mongolica) were used to study the effects of acetylene (C2H2) at low concentrations on nitrification, mineralization and microbial biomass N concentrations of the soils, and to assess the contribution of heterotrophic nitrification to nitrous oxide (N2O) emissions from soils. The use of acetylene at partial pressures within a range from 10 to 100 Pa C2H2 in headspace gas gave a significant decrease in N2O emission at soil moisture of c. 45% water-filled porosity space, and the decrease was almost the same in each soil after exposure of C2H2 at low concentrations. Heterotrophic nitrification could account for 21%―48% of total N2O emission from each soil; the contribution would increase with increasing distances from the Pinus koraiensis trunks rather than from the Quercus mongolica trunks. Under the experimental conditions, the use of C2H2 at low concentrations showed no significant influ- ence on soil microbial biomass N, net N mineralization and microbial respiration. However, 100 Pa C2H2 in headspace gas could reduce carbon dioxide (CO2) emissions from soils. According to the rapid consumption of 10 Pa C2H2 by forest soils and convenience for laboratory incubations, 50 Pa C2H2 in headspace gas can be used to study the origin of N2O emissions from forest soils under aerobic con- ditions and the key associated driving mechanisms. The N2O and CO2 emissions from the soils at the same distances from the Quercus mongolica trunks were larger than those from the Pinus koraiensis trunks, and both emissions decreased as the distances from trunks increased. The stepwise regression analysis showed that 95% of the variability in soil CO2 emissions could be accounted for by the concentrations of soil total C and water soluble organic C and soil pH, and that 72% of the variability in soil N2O emissions could be accounted for by the concentrations of soil total N, exchangeable NH+4-N and microbial biomass N and 25% ofTemperate forest surface soils at the varying distances from main trunks （e.g., Pinus koraiensis and Quercus mongolica） were used to study the effects of acetylene （C2H2） at low concentrations on nitrification, mineralization and microbial biomass N concentrations of the soils, and to assess the contribution of heterotrophic nitrification to nitrous oxide （N=O） emissions from soils. The use of acetylene at partial pressures within a range from 10 to 100 Pa C2H2 in headspace gas gave a significant decrease in N20 emission at soil moisture of c. 45% water-filled porosity space, and the decrease was almost the same in each soil after exposure of C2H2 at low concentrations. Heterotrophic nitrification could account for 21%--48% of total N20 emission from each soil; the contribution would increase with increasing distances from the Pinus koraiensis trunks rather than from the Quercus mongolica trunks. Under the experimental conditions, the use of C2H2 at low concentrations showed no significant influ- ence on soil microbial biomass N, net N mineralization and microbial respiration. However, 100 Pa C2H2 in headspace gas could reduce carbon dioxide （CO2） emissions from soils. According to the rapid consumption of 10 Pa C2H2 by forest soils and convenience for laboratory incubations, 50 Pa C2H2 in headspace gas can be used to study the origin of N20 emissions from forest soils under aerobic conditions and the key associated driving mechanisms. The N2O and CO2 emissions from the soils at the same distances from the Quercus mongolica trunks were larger than those from the Pinus koraiensis trunks, and both emissions decreased as the distances from trunks increased. The stepwise regression analysis showed that 95% of the variability in soil CO2 emissions could be accounted for by the concentrations of soil total C and water soluble organic C and soil pH, and that 72% of the variability in soil N2O emissions could be accounted for by the concentrations of soil total N, exchangeable NH^＋ 4-N and microbial bio

关 键 词：氮化合 森林土壤 微生物 周转基 

分 类 号：S714[农业科学—林学]