Effect of vegetation type, wetting intensity, and nitrogen supply on external carbon stimulated heterotrophic respiration and microbial biomass carbon in forest soils

作     者：WU HaoHao XU XingKai DUAN CunTao LI TuanSheng CHENG WeiGuo Wu H H;Xu X K;Duan C T;Li T S;Cheng W G

作者机构：State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry Institute of Atmospheric PhysicsChinese Academy of Sciences College of Earth Science University of Chinese Academy of Sciences College of Earth Science and Resources Chang'an University Faculty of Agriculture Yamagata University 

出 版 物：《Science China Earth Sciences》 (中国科学（地球科学英文版）)

年 卷 期：2015年第58卷第6期

页      面：1446-1456页

核心收录：

学科分类：09[农学] 0903[农学-农业资源与环境] 090301[农学-土壤学] 

基　　金：financially supported jointly by the National Basic Research Program of China(Grant No.2010CB950602) the National Natural Science Foundation of China(Grant Nos.41175133,21228701,41275166,and 41321064) 

主　　题：dissolved organic carbon forest soil glucose heterotrophic respiration microbial biomass carbon nitrogen supply stimulating effect 

摘      要：By using packed soil-core incubation experiments, we have studied stimulating effects of addition of external carbon （C） （glu- cose, 6.4 g C m 2） on heterotrophic respiration and microbial biomass C of a mature broadleaf and Korean pine mixed forest （BKPF） and an adjacent white birch forest （WBF） soil under different wetting intensities （55% and 80% WFPS, water-filled pore space） and nitrogen （N） supply （NH4C1 and KNO3, 4.5 g N m-e） conditions. The results showed that for the control, the cumulative carbon dioxide （CO2） flux from WBF soil during the 15-day incubation ranged from 5.44 to 5.82 g CO2-C m-2, which was significantly larger than that from BKPF soil （2.86 to 3.36 g CO2-C m 2）. With increasing wetting intensity, the cumulative CO2 flux from the control was decreased for the WBF soil, whereas an increase in the CO2 flux was observed in the BKPF soil （P 〈 0.05）. The addition of NH4C1 or KNO3 alone significantly reduced the cumulative CO2 fluxes by 9.2%-21.6 % from the two soils, especially from WBF soil at low wetting intensity. The addition of glucose alone significantly increased soil heterotrophic respiration, microbial biomass C （MBC）, and microbial metabolic quotient. The glucose-induced cumulative CO2 fluxes and soil MBC during the incubation ranged from 8.7 to 11.7 g CO2-C m-2 and from 7.4 to 23.9 g C m-2, which are larger than the dose of added C. Hence, the addition of external carbon can increase the decomposition of soil native organic C. The glucose-induced average and maximum rates of CO2 fluxes during the incubation were significantly in- fluenced by wetting intensity （WI） and vegetation type （VT）, and by WIxVT, NH4ClxVT and WIxVTxNH4C1 （P〈0.05）. The addition of NH4C1, instead of KNO3, significantly decreased the glucose-induced MBC of WBF soil （P〈0.05）, whereas adding NH4C1 and KNO3 both significantly increased the glucose-induced MBC of BKPF soil at high moisture （P〈0.05）. According to the differences in soil labile C pools, MBC and CO2 fluxes