不同林龄马尾松人工林土壤微生物量碳氮含量变化规律研究

土壤微生物量是森林生态系统中重要的组成部分,在森林生态系统的碳氮循环中起着重要作用。采用氯仿熏蒸浸提法测定了红壤丘陵区不同林龄马尾松人工林土壤微生物碳和氮,并分析了其与土壤理化性质之间的相关性。结果表明:淤马尾松人工林土壤微生物量碳(MBC)和氮(MBN)含量均呈现成熟林显著高于中龄林和幼龄林(P<0.05);于土壤微生物量碳和氮之比(MBC/MBN)在不同林龄之间也存在显著差异,且成熟林最大,为28.41依1.03;盂微生物量碳氮之间以及土壤微生物量碳氮与土壤有机碳、全氮、土壤pH值、土壤含水率、土壤C/N呈极显著正相关(P<0.01),而与土壤容重之间呈显著负相关(P<0.05)。上述结果表明,研究区马尾松人工林土壤微生物量碳氮与土壤理化性质密切相关,成熟林土壤养分状况最优。

Change Regularity of Soil Microbial Biomass C and N in Man-made Forest of Pinus massoniana at Different Ages

Soil microbial biomass is an important component of forest ecosystem and plays an crucial role in the cycle of carbon and nitrogen in the forest ecosystem. By the method of chloroform fumigation extraction,the microbial biomass carbon（MBC）and the microbial biomass nitrogen（MBN）of Pinus massoniana Lamb. at different ages were tested in red soil hilly region,and the relationship between soil microbial biomass and the soil physical and chemical properties were also analyzed in this study. The result showed that①the microbial biomass carbon and nitrogen of Pinus massoniana Lamb. were significantly higher in the mature plantation forests than those in the young and in the middle-aged forests（P〈0.05）;②the MBC/MNB of Pinus massoniana Lamb. at different ages were significantly different with the highest in the mature forest was 28.41±1.03;③The MBC and MNB were significantly positively correlated with each other（P〈0.01）,the MBC and MNB were significantly positively correlated with soil organic carbon（SOC）,total nitrogen（TN）,soil pH,soil water content,soil C/N（P〈0.01）,and significantly negatively correlated with soil bulk density（P〈0.05）. The above results suggested that the MBC and MNB had a closely relation with soil physical and chemical properties,and the soil nutrients in the mature plantation forests were the best.