林火干扰后大兴安岭森林土壤磷的变化特征

Change characteristics of forest soil phosphorus after fire in Great Xing’an Mountains

以大兴安岭呼中自然保护区2000和2010年火场为研究区,附近未过火区为对照,综合分析火后5和16年凋落物、矿物层和有机层土壤P含量的变化。结果表明:相较于对照,火后5年,矿物层土壤P含量显著增加39%,有机层土壤P含量显著增加28%,而凋落物P含量显著减少34%;火后16年,矿物层土壤和凋落物的P含量仍与对照差异显著,而有机层土壤P含量恢复至火前水平。火后5和16年,林火烈度与土壤总P含量不相关;而土壤性质与凋落物、土壤P含量密切相关。对照区,凋落物P含量与矿物层土壤湿度和pH显著相关;火后5年,凋落物P含量与有机层土壤pH显著相关;火后16年,有机层土壤和凋落物的P含量与矿物层土壤湿度显著相关。研究表明,林火对大兴安岭森林土壤磷的影响较为持久,且这种影响与土壤环境密切相关。

In this study, we investigated the changes in total phosphorus (P) of litter and the mineral and the organic soil after fires in one control and two burned sites burning in the year 2000 and 2010 at the Huzhong Natural Reserve in the Great Xing an Mountains of Northeastern China. Compared to the control, wildfire significantly increased the mineral and the organic soil total P by 39% and 28%, respectively, but significantly decreased litter total P by 34% in the 5-year-post-fire site. Sixteen years after the fire, mineral soil and litter total P were still significantly different from the control but the organic soil total P recovered to pre-fire levels. The correlation analysis showed that there were no significant correlations between fire severity and total phosphorus of litter and the mineral and the organic soil in the two burned sites. There were close associations between soil phosphorus and soil properties. In the control, litter total P was significant correlated with mineral soil water content and pH, whereas in the 5-year-post-fire site, litter total P was greatly correlated with organic soil pH. In contrast, in the 16-year-post-fire site, litter and organic soil total P were mainly related to mineral soil water content. These results suggest that effects of wildfire on soil phosphorus are long-term and such effects are closely associated with post-fire soil environments.