鼎湖山针阔混交林土壤热状况研究

选取2003年1月1日-12月31日的土壤热状况实测数据，探讨了鼎湖山针阔混交林各层次土壤温度、土壤热通量及与净辐射的关系．结果表明：随土层深度的增加，土壤温度日变化振幅越来越小，40cm深度处土壤温度几乎没有明显的日变化；越接近地表，土壤温度月变化越剧烈；不同时间尺度上不同深度处土壤温度与净辐射之间存在极显著的线性相关关系（P〈0．0001）；5cm深度处土壤热通量振幅明显小于表层，且日变化节律也延滞0．5-1．0h；表层土壤热通量对冠层净辐射的反馈延滞约2．5h，而5cm深度处土壤热通量则延滞3．5h，同时净辐射与表层土壤热通量的相关性更为密切．

Study on the Soil Thermal Conditions of Coniferous and Broad-Leaved Mixed Forest in Dinghushan Reserve

Based on the soil thermal measurements from Jan.1stto Dec.31th,2003,the soil temperatures,soil thermal fluxes,the relationship between soil temperatures and net radiation,soil thermal fluxes and net radiation of coniferous and broad-leaved mixed forest in Dinghushan Reserve were discussed in this paper.The following results were gotten:(1) The diurnal changes of soil temperature decreased with the depth of soil layers,and no obvious diurnal changes of soil temperature was detected at the depth of 40 cm.(2) The monthly soil temperature varied acutely at the soil surface layers.(3) There existed significant linear relationship(P<0.000 1) between soil temperature and net radiation at different temporal scales.(4) The changes of thermal fluxes swings at 5 cm soil layer were much milder than that of the surface soil layer,and the diurnal changes of thermal fluxes at 5 cm soil layer lagged behind the surface soil about 0.5-1.0 h.(5) The feedback of the surface soil heat fluxes lagged 2.5 h behind the net radiation,while the soil heat fluxes at 5 cm depth lagged 3.5 h.The soil heat fluxes of the surface soil were more closely related to the net radiation.