Aggregate stability and microbial community dynamics under drying-wetting cycles in a silt loam soil
Aggregate stability and microbial community dynamics under drying-wetting cycles in a silt loam soil
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DOI：
10.1016/j.soilbio.2005.12.022
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发表时间：
2006-08-01
影响因子：
9.7
通讯作者：
Le Bissonnais, Yves
中科院分区：
文献类型：
--
作者：
Cosentino, Diego;Chenu, Claire;Le Bissonnais, Yves
团聚体的稳定性往往表现出很大的年际和季节性变化，无论残留物的处理，往往是大于土壤或种植系统之间的差异。土壤湿度的变化和微生物活动的季节性刺激经常被认为是主要原因。本文的目的是评估干燥-再润湿循环对骨料稳定性的影响，并从机械角度对其主要微生物介导剂进行评价。将粉质土壤的3-5 mm团聚体在20 ℃下孵育63天，并进行以下处理及其组合：（i）有或没有秸秆投入，以及（ii）有或没有暴露于四个干湿循环。通过测定土壤呼吸来跟踪微生物活性。通过测定热水可提取碳水化合物-C、微生物生物量碳和麦角甾醇含量，评价了微生物菌剂的聚集稳定性。根据Le Bissonnais [1996]，我们测量了水滴渗透时间以估计疏水性和聚集体稳定性。土壤团聚体稳定性与土壤可蚀性和可结性评价：I。理论和方法。European Journal of Soil Science 47，425-437]来区分三种分解机制：熟化、机械分解和微裂纹。秸秆的添加刺激了微生物活性，提高了团聚体对三种稳定性试验的抵抗力，增强了团聚体的内部凝聚力和疏水性。所有估算的团聚体稳定性微生物菌剂对有机质的添加反应积极，且与团聚体稳定性高度相关。真菌生物量与聚集体稳定性的相关性比总微生物生物量更好，表明真菌的三重贡献：物理缠结，胞外多糖和疏水物质的产生。干湿循环对骨料稳定性的影响小于秸秆的加入，但当微生物活性被刺激时，它们的影响更加明显，表现出积极的相互作用。(c)2006爱思唯尔有限公司保留所有权利。
Aggregate stability often exhibits a large inter-annual and seasonal variability which occurs regardless of residue treatments and is often larger than the differences between soils or cropping systems. Variations in soil moisture and seasonal stimulation of microbial activity are frequently cited as the major causes. The goal of this paper was to evaluate the effects of drying-rewetting cycles on aggregate stability and on its main microbially mediated agents from a mechanistic point of view. The 3-5 mm aggregates of a silty soil were incubated at 20 degrees C for 63 days with the following treatments and their combinations: (i) with or without straw input and (ii) with or without exposure to four dry-wet cycles. Microbial activity was followed by measuring the soil respiration. We estimated the microbial agents of aggregate stability measuring hot-water extractable carbohydrate-C, microbial biomass carbon and ergosterol content. We measured the water drop penetration time to estimate the hydrophobicity and aggregate stability according to Le Bissonnais [1996. Aggregate stability and assessment of soil crustability and erodibility: I. Theory and methodology. European Journal of Soil Science 47, 425-437] to distinguish three breakdown mechanisms: slaking, mechanical breakdown and microcracking. The addition of straw stimulated microbial activity and increased the resistance to the three tests of aggregate stability, enhancing the internal cohesion and hydrophobicity of aggregates. All the estimated microbial agents of aggregate stability responded positively to the addition of organic matter and were highly correlated with aggregate stability. Fungal biomass correlated better with aggregate stability than total microbial biomass did, showing the prominent role of fungi by its triple contribution: physical entanglement, production of extracellular polysaccharides and of hydrophobic substances. Dry-wet cycles had less impact on aggregate stability than the addition of straw, but their effects were more pronounced when microbial activity was stimulated demonstrating a positive interaction. (c) 2006 Elsevier Ltd. All rights reserved.