树种和凋落物对杉木林土壤微生物性质的影响

Effects of Broad-leaved Trees and Litter on Productivity and Soil Microbes of Chinese Fir Plantation

调查了两个阔叶树种(固氮树种桤木Alnus cremastogyne Burkill和非固氮树种五角枫Acer mono Maxim)及凋落物施放对杉–阔混交林生物量和土壤微生物性质的影响.结果表明,杉–阔混交林中杉木生物量没有显著差异(P>0.05),杉木–桤木混交林总生物量比杉木–五角枫多200%(P<0.05),增加的生物量源于阔叶树种的差异.凋落物对两个类型混交林的生物量都没有产生显著影响(P>0.05).桤木混交处理0～10cm层土壤的土壤有机碳增加了16.8%,而土壤基础呼吸和呼吸熵下降了13.1%和16%.覆盖凋落物使0～10cm层的微生物量碳增加了10.8%,此外,树种和凋落物对土壤基础呼吸和呼吸熵有显著的交互作用(P<0.05).土壤有机碳和树木的生物量呈显著的正相关(R=0.775,P=0.005,N=12).不考虑处理间的差异,土壤微生物量碳与土壤有机碳(R=0.438,P=0.032,N=24)、可溶性有机碳(R=0.0.541,P=0.006,N=24)具有显著的相关性.混交林树种的选择和凋落物对杉–阔混交林林地土壤微生物学性质都具有重要的作用.

The effects of broad-leaved tree introduction and litter formation on the productivity and soil microbial properties were investigated in the Chinese fir [Cunminghamia lanceolata （Lamb） Hook] plantation. The results showed that the productivity was increased by 200% after the introduction of N-fixing Alnus cremastogyne （AC） compared with that of non- N-fixing Acer mono （AM） , and the increment was obtained from A. cremastogyne. The productivity of fir was not affected by tree species （P〉0.05）. A. cremastogyne increased the total organic C by 16.8%, and decreased soil basal respiration and qCO2 by 13.1% and 16% in 0~10 cm soil, respectively. The microbial biomass C in soil at 0-10 cm depth was increased by 10.8% by litter （P〉0.05）. Furthermore, the tree species and litter had significant interactive effects on soil basal respiration and qCO2 （P〉0.05）. The total organic C in 0-10 cm soil was positively related with the productivity of tree （R^2=0.775, P=0.005, N=12）, and the microbial biomass C was significantly related with total organic C （R^2=0.438, P=0.032, N=24）. The results suggested that the tree species and litter were both important to soil microbial properties in mixed plantation. Fig 3, Tab 2, Ref 23