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冀北辽河源自然保护区土壤微生物碳代谢特征对凋落物分解主场效应的响应

立天宇,康峰峰,韩海荣**,高晶,宋小帅,于舒   

  1. (北京林业大学林学院, 北京 100083)
  • 出版日期:2015-07-18 发布日期:2015-07-18

Responses of soil microbial carbolic metabolism characteristics to home-field advantage of leaf litter decomposition in Liaoheyuan Nature Reserve of northern Hebei Province, China.

LI Tian-yu, KANG Feng-feng, HAN Hai-rong, GAO Jing, SONG Xiao-shuai, YU Shu   

  1. (College of Forestry, Beijing Forestry University, Beijing 100083, China)
  • Online:2015-07-18 Published:2015-07-18

摘要: 通过凋落物袋法研究了冀北辽河源地区表层0~5、5~10和10~20 cm土壤微生物生物量碳、微生物呼吸速率和微生物代谢熵对白桦及蒙古栎叶凋落物分解主场效应的响应过程.结果表明: 主场白桦及蒙古栎凋落物处理土壤微生物生物量碳显著高于客场;而土壤微生物呼吸则差异不显著.土壤微生物生物量碳、微生物呼吸对不同植物凋落物分解主场效应的响应程度也不一致.客场蒙古栎叶凋落物处理各土层土壤微生物生物量碳相比主场降低了39.6%、34.9%、33.5%;白桦凋落物则降低了31.6%、27.1%、17.0%.客场蒙古栎凋落物微生物呼吸分别为主场的96.3%、92.4%、83.7%,白桦凋落物为99.4%、97.3%、101.3%.微生物代谢熵则呈现出与微生物生物量碳相反的变化趋势.植物凋落物在主场分解速率较快,可供微生物利用的养分较多,促进了土壤微生物的活动,且土壤中丰富的有机质削弱了植物摄取与微生物需求之间的矛盾,进而导致土壤微生物生物量碳及微生物代谢熵对叶凋落物分解主场效应产生了明显的响应.而土壤微生物呼吸由于受到林地内土壤温度、含水率以及二者共同作用的影响,对主场效应表现出了微弱的响应.此外,由于低质量凋落物会表现出更强的主场效应,从而使土壤微生物生物量碳、微生物呼吸及微生物代谢熵对白桦叶凋落物分解主场效应的响应程度低于蒙古栎凋落物.

Abstract: Using litter bag method, we studied the responses of soil microbial biomass carbon (MBC), microbial respiration (MR) and microbial metabolic quotient (qCO2) in 0-5 cm, 5-10 cm and 10-20 cm soil layers to homefield advantage of Betula platyphlla and Quercus mongolica leaf litter decomposition in Liaoheyuan Nature Reserve, northern Hebei Province. The results showed that the contents of MBC in Betula platyphlla and Quercus mongolica leaf litter treatments in home environment (Bh and Qh treatments) were significant higher than that in B. platyphlla and Q. mongolica leaf litter treatments in nonhome environment (Ba and Qa treatments). There was no significant difference in MR between home and nonhome environments. Response degree of MBC and MR to homefield advantage of different litter decomposition was inconsistent. The MBC of the different soil layers in Qa treatment fell by 39.6%, 34.9% and 33.5% compared to Qh treatment, respectively, and that in B. platyphlla treatment was decreased by 31.6%, 27.1% and 17.0%, respectively. MR of the different soil layers in Qa treatment accounted for 96.3%, 92.4% and 83.7% of Qh treatment, respectively, while MR in B. platyphlla treatment was 99.4%, 97.3% and 101.3%, respectively. In contrast to MBC, qCO2 in soil showed a reverse pattern. Our study suggested that rich nutrients in soil enhanced microbial activity and weakened the conflict of nutrient uptake between plants and microorganisms, which led to the result that MBC and qCO2 had an obvious response to homefield advantage of litter decomposition, when litter decomposed in its home environment. There was a weak response between MR and homefield advantage of litter decomposition, because of influence of soil temperature, water content and their interaction. Furthermore, MBC, MR and qCO2 had a higher response degree to homefield advantage of Q. mongolica litter than B. platyphlla litter, since lower quality litter exhibited higher homefield advantage of litter decomposition.