阔叶幼林取代杉木林后的土壤肥力研究

研究了3种阔叶混交幼林的土壤肥力，并将其肥力特征与杉木幼林进行对比研究。3种林分的立地条件相似常绿阔叶混交林1由12种观赏树种组成，常绿阔叶混交林2由7种速生乡土阔叶树种组成，常绿阔叶混交林3由12种阔叶树种组成。结果表明，各林地的土壤呈强酸性。常绿阔叶混交林1的土壤有机质、全氮和有效磷含量居各林地之首，其余的养分含量也大于或近似于杉木林地；常绿阔叶混交林2的全磷、全钾、有效氮、有效钾含量在4种林分中最高，有机质、全氮和有效磷含量也较高，说明这两种阔叶混交林有效地改善了土壤养分状况。常绿阔叶混交林3的土壤有机质、全氮和有效氮含量大于杉木林地，但是全磷、全钾、有效磷、有效钾含量小于后者。常绿阔叶混交林地1和常绿阔叶混交林地2的细菌、真菌和放线菌数量大于杉木林地，脲酶、磷酸酶、过氧化氢酶活性也较高，表明这2种阔叶混交林显著地改善了林地肥力。

Soil Fertility of Cunninghamia lanceolata lantation Replaced by Young Broadleaf Mixed Plantations

Soil fertilities of three young broadleaf mixed plantations were compared with those of a Cunninghamia lanceolata plantation. The soils of the broadleaf mixed plantations were rather strong in acidity. Among four plantations, the contents of soil organic matter, total N and available P were the highest in the first evergreen broadleaf mixed plantation, and its other nutrient contents were higher than the C. lanceolata plantation or similar to the latter; Total P, total K, alkalized N and available K were the highest in the second evergreen broadleaf mixed plantation, and its soil organic matter, total N and available P contents were greater than C. lanceolata plantation; Soil organic matter, total N and alkalized N of the third evergreen broadleaf mixed forest were greater than those of the C. lanceolata plantation, whereas its other nutrient contents were lower than the latter. The amounts of soil bacterium, fungi and actinomyces of the first and second evergreen broadleaf mixed plantations were greater than those of C. lanceolata plantation, and their urease, phosphoric acid enzyme and catalase activities were high, indicating that the two plantations significantly improved soil fertility.