磷添加对中亚热带2种森林类型土壤微生物群落组成的影响

摘要

We investigated the responses of soil microbial biomass, community composition and soil physicochemical properties to phosphorus(P) addition at level of 0(CT),0.1(LP),and 0.6(HP) g· kg -1 in natural Castanopsis carlesii forest and Cunninghamia lanceolata plantation in Geshikao Na-ture Reserve in Fujian Province of China.(1)After four months of P addition,the result demonstrated that P addition not only significantly increased total phosphorus and available phosphorus content,but also significantly increased soil pH and dissolved organic carbon content.(2)The specific influences of P addition on soil microbial community composition base on types of forest soils and the level of P. The abundance of soil total phospholipid fatty acid(PLFA),bacterial PLFA,fungal PLFA,gram-posi-tive bacterial PLFA,gram-negative bacterial PLFA and actinomycetes PLFA in two forest soil increased in the HP treatment.Low P addition only significant increased soil microbial PLFA and the ratio of gram-positive bacteria to gram-negative bacteria(GP/GN) in C.lanceolata plantation.The ratio of fungi to bacteria(F/B) was not significant changed with P addition in two forest soil.This finding in-dicates that P availability is maybe not the limiting factor for microbial growth in C.carlesii forest soil. However,the soil microorganisms may be limited by phosphorus nutrient due to nutrient loss after con-version from C.carlesii forest to C.lanceolata plantation.Therefore, proper phosphorus application is beneficial to sustainable management of C.lanceolata plantation.%以福建省三明市格氏栲自然保护区米槠(Castanopsis carlesii)天然林土壤和杉木(Cun-ninghamia lanceolata)人工林土壤为研究对象,通过不同梯度(对照CT-0 g·kg-1、低磷LP-0.1 g·kg-1、高磷HP-0.6 g·kg -1)磷添加室内培养实验,采用磷脂脂肪酸(PLFA)分析法,研究磷添加对中亚热带米槠天然林和杉木人工林土壤微生物生物量和群落组成的影响,结果表明:1)施磷除显著提高总磷和有效磷含量外,亦显著增加土壤pH和可溶性有机碳的含量;2)土壤微生物生物量和群落组成对磷添加的响应因施磷量和森林类型不同而不同,其中高磷处理显著增加杉木人工林和米槠天然林土壤微生物PLFA,杉木人工林增幅大于米槠天然林.低磷处理仅显著增加杉木人工林土壤微生物PLFA,对米槠天然林土壤微生物生物量影响不显著;磷添加显著增加杉木人工林土壤革兰氏阳性菌与革兰氏阴性菌的比值(GP/GN),对2种森林土壤真菌与细菌比(F/B)影响不显著.该研究表明米槠天然林转变成杉木人工林后,养分流失,加剧了磷限制.因此适当施磷有利于杉木人工林可持续经营.