不同林型天然红松混交林林隙大小和枯叶分解对土壤微生物碳的影响

目的]分析凉水国家级自然保护区不同林型天然红松混交林林隙大小、凋落物放置位置和采样时间对土壤微生物碳(SMBC)的影响,揭示影响本地区SMBC变化的因素,为天然红松混交林生态系统碳循环的研究提供基础数据。方法]在天然红松混交林3种林型的大、中、小林隙内不同位置的土壤表层放置装有红松、椴树、枫桦枯叶的分解袋,并以各自的郁闭林分为对照,在2012年植物生长季的6—9月,每月采集枯叶分解袋下0 10 cm土层土样,采用氯仿熏蒸-K2SO4浸提法测定SMBC。结果]在椴树红松混交林(TP)内,林隙大小对SMBC的影响依次为小林隙大林隙中林隙;在云冷杉红松混交林(PAP)内,依次为中林隙大林隙小林隙;在枫桦红松混交林(BP)内,依次为大林隙中林隙小林隙。3种林型下,采样时间(月份)对SMBC均有显著的影响(P0.05);林隙大小对其影响均不显著(P0.05);枯叶分解袋放置位置对大、中、小林隙内SMBC的影响均不显著(P0.05)。结论]不同林型下林隙大小对SMBC的影响排列顺序不同;枯叶分解袋放置位置对天然红松混交林3种林型大、中和小林隙内SMBC的影响均未达到显著水平。

Effects of Gap Size and Dead Leaf Decomposition on Soil Microbial Biomass Carbon in Different Stand Types of Natural Pinus koraiensis Mixed Forest

Objective]The effects of gap size, the place of dead leaves and sampling time on soil microbial biomass carbon (SMBC) under different forest types in Liangshui National Nature Reserve were analyzed aiming at revealing the factors influencing the variation in SMBC in the study area. The purpose of this study is to obtain the basic data and lay a theoretical foundation for the accurate evaluation on soil carbon storage in natural Pinus koraiensis mixed forest ecosystem. Method]Decomposition bags of dead leaves of Pinus koraiensis, Tilia amurensis, Betula costata were placed in the soil surface at different positions of large, medium and small gaps and the corresponding closed forest (control) in three forest types of natural Pinus koraiensis mixed forest. The soil samples in the depth of 010 cm under decomposition bags of dead leaves were collected monthly from June to September during the 2012 growing season. The SMBC was measured by the method of Chloroform fumigation-K₂SO₄ extraction. Result]The effects of gap size on SMBC in Tilia amurensis-Pinus koraiensis mixed forest was in the order of small gap > big gap > medium gap;medium gap > big gap > small gap in Picea spp.-Abies nephlolepis-Pinus koraiensis mixed forest; big gap > medium gap > small gap in Betula costata-Pinus koraiensis mixed forest. The effect of sampling time (month) on SMBC was significant (P<0.05) in all the three forest types, but the effect of gap size on SMBC was not significant (P>0.05). The effect of placement location of decomposition bags of dead leaves on SMBC was not significant (P>0.05) in large, medium, and small gap. Conclusion]The ranked order of the effect of gap size on SMBC was different under different forest types; the effect of placement location of decomposition bags of dead leaves on SMBC did not reach the significant level.