连作杨树人工林不同生长阶段林地内土壤微生态环境特征

Characteristics of Soil Micro-ecological Environment at Different Growth Stages of Poplar Plantation under Continuous Cropping

为了解连作杨树人工林不同生长阶段林地内的土壤微生态环境特征,分别选取山东省莒县招贤镇和峤山镇境内的连作杨树人工林地为研究对象,研究结果表明:土壤的物理性状随着林龄的增加先变差后又逐渐改善,而pH值随着林龄的增加是逐渐降低的。土壤养分和土壤脲酶活性随着林龄的增加呈现先增加后减小的趋势,过氧化物酶和多酚氧化酶活性随着林龄的增加而降低,过氧化氢酶活性随林龄的增加没有规律。除1龄林地外,细菌、放线菌数量及微生物总量随着林龄的增加先增加后减少,真菌数量随林龄的增加规律性不强。在土壤剖面上,土壤的物理性状随着土层的加深逐渐变差,肥力元素除了速效P和微量元素F e之外,在大部分林地内均表现出随着土层的加深而降低的趋势。土壤酶中的脲酶活性随着土层的加深而降低,表现出较强的规律性,而过氧化氢酶、过氧化物酶和多酚氧化酶在垂直方向上均没有规律性。特别是过氧化氢酶在招贤镇和峤山镇的试验地内结果正好相反。

Dynamics of soil micro-ecological environment at different growth stages of poplar plantation were studied in Zhaoxian town and Qiaoshan town of Ju county, Shandong province. The results showed ： with the plantation ages increased, soil physics property became worse, and then it became better than before. However, pH value decreased with plantation ages increased. Contents of soil nutrients and the activity of soil urease increased firstly, and then decreased. Peroxidase activity and polyphenol oxidase activity decreased with plantation ages increased ; however, catalase activity was not a significant law. With the poplar plantation ages increased, the number of bacteria and actinomyces and total number of soil microbes increased; however, the number of fungi was not a significant law. Compared with different soil layers, soil physical properties of the bottom layer were worse than the top layer. With the depth of soil layer increased, the contents of soil nutrients were decreased other than soil available P and soil micro element Fe. The activity of soil urease was decreased with the depth of soil layer increased; however, catalase activity, peroxidase activity and polyphenol oxidase activity were not significant law. Especially, compared with the two experimental sites, catalase activity showed reverse trends.