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马尾松和苦槠林根际土壤矿化和根系分解CO2释放的温度敏感性

刘煜1,胡小飞1**,陈伏生2,袁平成2   

  1. (1南昌大学生命科学与食品工程学院, 南昌 330031; 2江西农业大学林学院, 南昌 330045)
  • 出版日期:2013-06-18 发布日期:2013-06-18

Temperature sensitivity of CO2 fluxes from rhizosphere soil mineralization and root decomposition in Pinus massoniana and Castanopsis sclerophylla forests.

LIU Yu1, HU Xiao-fei1, CHEN Fu-sheng2, YUAN Ping-cheng2   

  1. (1College of Life Sciences and Food Engineering, Nanchang University, Nanchang 330031, China; 2College of Forestry, Jiangxi Agricultural University, Nanchang 330045, China)
  • Online:2013-06-18 Published:2013-06-18

摘要:

以中亚热带马尾松林和苦槠林为对象,原位收集根际和非根际土壤、树木不同生态功能的根系,开展15 ℃、25 ℃、35 ℃和45 ℃恒温培养模拟试验,采用密闭气室碱液吸收法测定53 d内CO2释放的动态变化.结果表明: 两种森林类型不同温度下土壤矿化CO2释放速率的根际效应介于1.12~3.09,且培养前期高于培养后期;15 ℃下马尾松林和苦槠林差异不显著,25 ℃和35 ℃下前者低于后者,45 ℃下则相反.不同培养温度下两树种吸收根分解的CO2释放速率均高于过渡根和贮存根,且马尾松均低于苦槠.两种森林类型CO2释放的Q10值均为土壤(1.21~1.83)显著高于根系(0.96~1.36).两种森林类型土壤矿化CO2释放的Q10值差异不显著,而马尾松根系分解CO2释放的Q10值高于苦槠.推断全球变暖导致的土壤矿化CO2释放的增量将远远高于根系分解,且马尾松林高于苦槠林;地带性顶极群落应对气候变化的抵抗力强于先锋树种群落.
 

Abstract: Rhizospheric and non-rhizospheric soils and the absorption, transition, and storage roots were sampled from the midsubtropical Pinus massoniana and Castanopsis sclerophylla forests to study the CO2 fluxes from soil mineralization and root decomposition in the forests. The samples were incubated in closed jars at 15 ℃, 25 ℃, 35 ℃, and 45 ℃, respectively, and alkali absorption method was applied to measure the CO2 fluxes during 53 days incubation. For the two forests, the rhizospheric effect (ratio of rhizospheric to non-rhizospheric soil) on the CO2 flux from soil mineralization across all incubation temperature ranged from 1.12 to 3.09, with a decreasing trend along incubation days. There was no significant difference in the CO2 flux from soil mineralization between the two forests at 15 ℃, but the CO2 flux was significantly higher in P. massoniana forest than in C. sclerophylla forest at 25 ℃ and 35 ℃, and in an opposite pattern at 45 ℃. At all incubation temperature, the CO2 release from the absorption root decomposition was higher than that from the transition and storage roots decomposition, and was smaller in P. massoniana than in C. sclerophylla forest for all the root functional types. The Q10 values of the CO2 fluxes from the two forests were higher for soils (1.21-1.83) than for roots (0.96-1.36). No significant differences were observed in the Q10 values of the CO2 flux from soil mineralization between the two forests, but the Q10 value of the CO2 flux from root decomposition was significantly higher in P. massoniana than in C. sclerophylla forest. It was suggested that the increment of CO2 flux from soil mineralization under global warming was far higher than that from root decomposition, and for P. massoniana than for C. sclerophylla forest. In subtropics of China, the adaptability of zonal climax community to global warming would be stronger than that of pioneer community.