目前已有的研究结果显示出调控森林土壤主要温室气体(CO2,CH4, N2O)通量的因素很多,如外部环境因子(温度、降水、氮沉降等),土壤特性(物理、化学、生物等)等,但如何量化这些因素的调控作用并没有得到很好的解决,成为这些气体通量模型发展的瓶颈。
华南植物园生态及环境科学研究中心闫俊华研究员等利用森林土壤移位(从河南鸡公山移到广东鼎湖山)实验,通过比较相同土壤在不同外部环境因子条件下,或不同土壤在相同外部环境因子条件下主要温室气体通量的差异,发现外部环境因子是森林土壤CO2和N2O气体通量的决定因素,而土壤是森林土壤CH4气体通量的决定因素,并通过模型模拟和实际观测值的比较对上述结果进行了验证。研究给森林土壤主要温室气体模型建立所考虑的参数以重要启示,如土壤的物理、化学和生物的特征参数是建立森林土壤CH4气体通量模型所考虑的重点。(生物谷Bioon.com)
生物谷推荐的英文摘要
Global Change Biology doi: 10.1111/gcb.12327
Responses of CO2, N2O and CH4 fluxes between atmosphere and forest soil to changes in multiple environmental conditions
JUNHUA YAN, WEI ZHANG, KEYA WANG, FEN QIN, WANTONG WANG,HUITANG DAI and PEIXUE LI
To investigate the effects of multiple environmental conditions on greenhouse gas (CO2, N2O, CH4) fluxes, we transferred three soil monoliths from Masson pine forest (PF) or coniferous and broadleaved mixed forest (MF) at Jigongshan to corresponding forest type at Dinghushan. Greenhouse gas fluxes at the in situ (Jigongshan), transported and ambient (Dinghushan) soil monoliths were measured using static chambers. When the transported soil monoliths experienced the external environmental factors (temperature, precipitation and nitrogen deposition) at Dinghushan, its annual soil CO2 emissions were 54% in PF and 60% in MF higher than those from the respective in situ treatment. Annual soil N2O emissions were 45% in PF and 44% in MF higher than those from the respective in situ treatment. There were no significant differences in annual soil CO2 or N2O emissions between the transported and ambient treatments. However, annual CH4 uptake by the transported soil monoliths in PF or MF was not significantly different from that at the respective in situ treatment, and was significantly lower than that at the respective ambient treatment. Therefore, external environmental factors were the major drivers of soil CO2 and N2O emissions, while soil was the dominant controller of soil CH4 uptake. We further tested the results by developing simple empirical models using the observed fluxes of CO2 and N2O from the in situ treatment and found that the empirical models can explain about 90% for CO2 and 40% for N2O of the observed variations at the transported treatment. Results from this study suggest that the different responses of soil CO2, N2O, CH4 fluxes to changes in multiple environmental conditions need to be considered in global change study.