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林火是北方针叶林生态系统最重要的自然驱动力,影响元素的生物地球化学循环。火后演替初期(<15年)是决定火后植被结构与功能恢复的关键时期,火后土壤养分的变化是影响火后植被结构与功能恢复的重要因子。本文选择大兴安岭呼中自然保护区火烧迹地作为研究对象,并选择附近未火烧区作为对照区,分析了火后1、5和11年土壤矿物层总磷含量及有效磷供给速率的变化。结果表明:相较于对照区,火后1年,土壤总磷(TP)含量与有效磷供给速率均显著增加,其中TP显著增加了55%,有效磷含量增加了270%;且土壤TP含量、有效磷供给速率均与林火烈度呈显著正相关。火后5和11年时,土壤TP含量仍显著高于对照区,但土壤TP含量与林火烈度间不存在显著相关关系。而在火后11年时,土壤有效磷供给速率则已恢复至火前水平。土壤TP、有效磷供给速率则均与土壤水分含量之间存在显著正相关关系。本研究显示,火后演替初期土壤磷含量表现为火后立即增加,然后随火后时间增加而逐渐减少;林火烈度在短期内对土壤磷含量具有重要影响,随演替时间增加,土壤性质则成为影响土壤磷含量的重要因子。
Forest fires are the most important natural driving force in the coniferous forest ecosystems and affect the biogeochemical cycles of the elements. The early stage of post-fire succession (<15 years) is the critical period for deciding the structure and function of post-fire vegetation. The change of soil nutrient after fire is an important factor that affects the structure and function recovery of post-fire vegetation. In this paper, we selected the burned area of Huzhong Nature Reserve in Daxing’anling as the research object, and selected the nearby un-burned area as the control area, and analyzed the changes of total phosphorus content and available phosphorus supply rate in soil mineral layers after 1, 5 and 11 years. The results showed that total phosphorus (TP) content and available phosphorus supply rate increased significantly after 1 year of fire, in which the TP increased 55% and the available phosphorus increased 270% compared with the control. The soil TP content , Available phosphorus supply rate and forest fire intensity were significantly positive correlation. At 5 and 11 years after fire, soil TP content was still significantly higher than the control area, but there was no significant correlation between soil TP content and forest fire intensity. However, at the 11th year after the fire, the rate of available phosphorus in soil was restored to the pre-fire level. There was a significant positive correlation between soil TP and available phosphorus supply rate and soil moisture content. In this study, the soil P content in the initial post-fire succession increased immediately after the fire and then decreased with the increase of the post-fire time. The forest fire intensity had a significant impact on the soil P content in the short term. With the increase of the succession time, Nature has become an important factor affecting the soil phosphorus content.