武夷山植被带土壤微生物量沿海拔梯度的变化

Variations of soil microbial biomass across four different plant communities along an elevation gradient in Wuyi Mountains,China

土壤微生物量是陆地生态系统碳循环的重要组成部分,在森林生态系统物质循环和能量转化中占有特别重要的地位。以武夷山常绿阔叶林(EBF)、针叶林(CF)、亚高山矮林(DF)和高山草甸(AM)为试验对象,研究了土壤微生物量沿海拔梯度的变化特征。结果表明:在0～10cm土壤层,随着海拔高度的增加,年平均土壤微生物量增大,AM的年平均土壤微生物量为4.07g·kg-1,分别为DF、CF和EBF的2.06、3.21倍和3.91倍;AM的年平均土壤微生物量显著大于DF、CF和AM(p<0.01),DF的年平均土壤微生物量显著大于EBF、CF(p<0.05),EBF和CF的年平均土壤微生物量无显著性差异(p>0.05),10～25cm土壤层的年平均土壤微生物量的变化规律与上层基本一致;在0～10cm土壤层,不同海拔年平均土壤微生物量分别与土壤有机碳、全氮、全硫含量以及土壤湿度呈显著正相关(p<0.05),在10～25cm土壤层,不同海拔年平均土壤微生物量分别与土壤有机碳、全氮含量呈显著正相关(p<0.05)。研究表明,武夷山亚热带森林年平均土壤微生物量随海拔高度升高而增加,土壤有机碳、全氮、全硫和土壤湿度可能是调控土壤微生物量沿海拔梯度变化的主要因子。

Soil microbial biomass carbon is an important component in carbon cycle of the terrestrial ecosystem. We chose Evergreen Broadleaf Forest （ EBF ）, Coniferous Forest （ CF ）, Dwarf Forest （ DF ） and Alpine Meadow （ AM ） as experimental sites along an elevation gradient in the national natural preserve of Wuyi Mountains, and to examine the variations of soil microbial biomass and its influencing factors from June, 2005 to April, 2006. The results showed that： （ 1 ） At 0 - 10cm depth of soil layer, the annual mean value of soil microbial biomass was increasing with increasing elevation. The soil microbial biomass of AM was 4.07 g, kg^-1, and which was 2.06, 3.21 and 3.91 times higher than that of DF, CF and EBF, respectively （p 〈0.01 ） , and the annual mean value of soil microbial biomass of DF was significantly higher than that of EBF, CF, respectively （p 〈 0.05 ）. However, the annual mean values of soil microbial biomass between DF and CF were not significantly different （p 〉0.05）. Variations of soil microbial biomass at 10 -25cm depth of soil layer was the same as that at 0-10cm depth of soil layer. （2）At 0-10cm soil layer, the annual mean values of soil microbial biomass were significantly correlated to soil organic carbon, total nitrogen, total sulphur and soil moisture, respectively. At 10 -25cm depth of soil layer, the annual mean values of soil microbial biomass were significantly correlated to soil organic carbon, total nitrogen, respectively. Our research showed that soil microbial biomass were increasing along the elevation gradient in subtropical forest in Wuyi Mountain, and soil organic carbon, total nitrogen, total sulfur or soil moisture might be the major factors controlling soil microbial biomass.