大兴安岭火烧迹地植被恢复中土壤微生物量及酶活性

Soil Microbial Biomass and Enzyme Activity in the Process of Vegetation Restoration in Burned Area of Great Xing'an Mountains

为了探讨火烧迹地植被恢复过程中土壤微生物量及酶活性变化特征,采用时空互代法,以大兴安岭重度火烧迹地不同恢复年限落叶松人工林为研究对象,对土壤微生物量碳、氮含量及脲酶、碱性磷酸酶、蔗糖酶和过氧化氢酶活性进行了研究.结果表明：（1）土壤养分含量均随土层深度的增加而降低,并在植被恢复过程中呈波动性变化,恢复24 a土壤全氮、全磷、有效磷和有机质含量均最高.（2）土壤微生物量碳和氮含量的变化范围分别为267.17～1 764.34mg/kg和23.45～182.14 mg/kg,随土层深度的增加而降低.随恢复年限的增加,土壤微生物量碳、氮含量呈上升趋势.（3）植被恢复过程中土壤脲酶、碱性磷酸酶、蔗糖酶和过氧化氢酶活性随土层深度的增加而降低,其中,恢复24 a落叶松人工林4种土壤酶活性均显著高于重度火烧迹地.（4）相关分析表明,土壤微生物量与土壤全磷、有效磷和有机质含量均极显著正相关,土壤酶活性与土壤全氮、全磷、水解氮和有机质含量极显著正相关,土壤生物学指标能较好地反映土壤肥力状况.火烧迹地经过24 a的恢复,土壤微生物量及酶活性得到了较好的改善.

In order to explore soil microbial biomass and enzyme activity in the process of vegetation restoration in burned area, the method of spatial sequence instead of time successional sequence was used and Larix gmelinii plantations at different restoration stages in severely burned area of great Xing＇ an mountains were selected as research object. Soil microbial biomass carbon and nitrogen content and the activities of urease, alkaline phosphatase, sucrase and catalase were studied. The results showed that： （1）Soil nutrient contents decreased with the increasing soil depth and fluctuated in the progress of vegetation restoration. The contents of soil total nitrogen, total phosphorus, available phosphorus and organic matter were the highest for 24 year-old plantation. （2） Soil microbial biomass carbon content ranged from 267. 17 mg/kg to 1 764. 34 mg/kg, while microbial biomass nitrogen content ranged from 23.45 mg/kg to 182.14 mg/kg. The contents of soil microbial biomass carbon and nitrogen decreased with the increasing soil depth and showed an increasing trend in the progress of vegetation restoration. （3）The activities of urease, alkaline phosphatase, sucrase and catalase decreased with the increasing soil depth in the progress of vegetation restoration, which were significantly higher in 24-year-old plantation than in severely burned area. （4）By using correlation analysis, we found that soil microbial biomass carbon and nitrogen were significantly positively related with soil total phosphorus, available phosphorus and organic matter content. Soil enzyme activity showed significant positive correlation with soil total nitrogen, total phosphorus, available nitrogen and organic matter. Therefore, soil biological properties can be used to evaluate soil fertility. Soil microbial biomass and enzyme activity of burned area were improved 24 years after vegetation restoration.