两种立地土壤水分物理性质对火烧的即时响应

Immediate response in edaphic hydro-physical properties under two site conditions after an experimental firein

为了了解火烧对土壤水分物理性质的影响,通过杨树林和裸地两种立地的林火点烧试验,对火烧前后样地土壤的水分物理性质进行了测定和比较研究。结果表明：在两种不同的立地中,随着土壤深度的增加,土壤体积密度增加,总孔隙度、持水量和饱和贮水能力减小。火烧后,0～5 cm土层的指标变率均大于≥5～10 cm土层的指标变率,因此土壤层间指标差值增大。杨树林的土壤体积密度低于裸地土壤体积密度,而其持水能力和总孔隙度均高于裸地。总体来看,火烧后的两种不同立地土壤的紧实度增加,通气透水性减弱,土壤孔隙的调节功能也随之减弱。杨树林土壤体积密度和持水能力受到火烧的即时干扰程度高于裸地,且其干扰程度随着火强度的增大而增强。

In order to understand the influences of fire on edaphic hydro-physical propertie,we determined and compared the edaphic hydro-physical properties under the poplars forest and bare land between pre-fire and post-fire. Results showed that under the different two site conditions,the soil bulk density increased,while the total porosity,water holding capacity and saturated water storage capacity decreased with the deepness of soil deepening. After the experimental fire,the variation range of indexes in 0-5 cm soil layer were greater than that in the ≥5-10 cm soil layer,so the difference rangeability of indexes between the soil layers increased. The soil bulk density of poplar forests was lower than that of the bare land,while the water holding capacity and total porosity were higher than those of the bare land. As a whole,soil density of poplar forest and bare land increased after fire but air permeability,water permeability and the regulating function of soil porosity decreased. Instant interference on soil bulk density of poplar forest and water holding capacity caused by fire were higher than that of the bare land,and the interference degree increased with the enhancement of the fire intensity. This research provides reference for improving edaphic hydro-physical properties by fire.