北京西山地区林火对土壤性质的影响

Influences of forest fire on soil properties in Xishan area of Beijing

为进行火烧迹地的管理,采用调查取样和室内分析方法,对北京西山地区不同林火强度下油松林土壤物理和化学性质的变化进行了研究。结果表明：与未火烧相比,中度火烧会显著提高土壤密度,显著降低土壤总孔隙度、土壤黏粒含量和田间持水量,而毛管孔隙和非毛管孔隙的变化却不明显;轻度火烧对土壤物理性质的影响不显著。轻度火烧会显著地提高0-5 cm范围的土壤有机质含量,而中度火烧会显著降低土壤有机质和全氮含量。轻度火烧使土壤pH值增加,其中0-2 cm的差异达到显著水平;另外,0-5 cm土层Ca^2＋和Mg^2＋的含量比中度火烧和未火烧土壤有明显的提高。因此,轻度火烧有利于改善土壤的性质。

In order to manage burned area, soil physic-chemical properties under Pinus tabulaeformis forest in different fire intensity in Beijing Xishan area were studied based on the field investigation and lab analysis. Results showed that the soil under moderate fire intensity was significantly higher the soil density, lower the total porosity, clay content and field capacity than unburned soil, the capillary and non capillary pores were nearly unchanged. The influence of low fire intensity on the physical properties was not significant. In 0 - 5 cm horizon, low fire intensity led to significantly increase the content of organic matter, however, moderate fire intensity led to significantly decrease the content of organic matter and total nitrogen. Low fire intensity led to increase soil pH, and the difference of soil pH in 0 - 2 cm horizon was significant. The contents of Ca^2＋ and Mg^2＋ in 0 - 5 cm horizon under low fire intensity were significant higher than that under moderate fire intensity and unburned. This paper showed also that the fire of low intensity could lead to improve the soil properties.