蚯蚓对土壤微生物残留物的影响研究评述与展望

蚯蚓如何影响土壤有机碳的固持是土壤生态学的关键科学问题之一。蚯蚓能同时促进土壤有机碳分解和稳定,这种两面作用带来的不确定性被研究者称为"蚯蚓困境"。研究证据和新兴的"土壤微生物碳泵"概念模型表明土壤微生物残留物是土壤有机质的主要贡献者。为系统了解蚯蚓对土壤微生物残留物的影响与可能的机制,研究分析和总结了已有的国内外蚯蚓与微生物残留物（氨基糖）的相关研究成果,表明：（1）过往的研究忽略了蚯蚓对微生物残留物的影响,导致这一方向的研究严重滞后;（2）蚯蚓对土壤微生物残留物影响的方向和大小仍有很大的不确定性,可供量化分析其驱动机制的研究还很缺乏。研究尝试将蚯蚓整合到"土壤微生物碳泵"概念框架中,分析蚯蚓影响土壤微生物残留物3个方面的可能机制,即：（1）改变土壤微生物量、群落结构,（2）改变微生物生理特性,（3）改变土壤团聚体结构等,影响土壤有机碳的积累。同时,本文提出了未来相关研究的6个重点方向,包括：（1）蚯蚓对微生物的选择性取食,（2）肠道介导的微生物"涨落"现象,（3）蚯蚓对矿质结合有机物的"破坏"与"重组",（4）蚯蚓引起的"激发"和"续埋"效应,（5）多生态型相互作用,（6）全球变化背景下的蚯蚓生态学等,以期为进一步揭示蚯蚓-微生物相互作用影响土壤有机碳累积与稳定性的机制提供参考。

Progress and prospect on earthworms' effects on soil microbial residues

How earthworm affects the accumulation of organic carbon in soils is one of the key questions in soil ecology. Earthworms promote soil organic carbon decomposition and stabilization simultaneously and this two-sided effect is known as the "Earthworm Dilemma". Evidences and the emerging conceptual model of the "soil microbial carbon pump" suggest that microbial residue is a major contributor to soil organic matter. By reviewing the researches on interaction effects between earthworm and microbial residues (amino sugars), we found that:(1) most of the previous studies neglected how do earthworms affect microbial residues, earthworms'' role in regulating microbial residues was seriously overlooked; (2) The direction and magnitude of the earthworms'' influence on soil microbial residue were of great uncertain, there was an extreme short of extensive researches for quantifying and analyzing the drivers and its mechanisms. This paper attempted to integrate earthworms'' effects into the conceptual model of "Soil Microbial Carbon Pump". We discussed 3 perspectives of possible mechanisms of how earthworms affected soil microbial residues, i.e. (1) modifying soil microbial biomass and community structure, (2) altering microbial physiological state, and (3) altering soil aggregate structure. Furthermore, we proposed 6 future research directions including:(1) earthworms'' selective feeding on microorganisms, (2) gut-mediated microbial "fluctuation" phenomenon, (3) "destruction and restruction" of mineral-associated organic matter, (4) induced "priming" and "entombing" effects, (5) multi-functional groups interactions, and (6) earthworm ecology in the context of global change. It aims to provide some guides for further understanding the effect of earthworm-microbial interaction on soil organic matter.