Background and aim

Litter and soil characteristics influence the abundance and activities of decomposers and detritivores, thereby affecting C accumulation. The relationship between the chemical composition of soil organic matter and soil organisms is still unclear. The study aims to investigate how the quality and quantity of litter and soil organic matter influence C accumulation and the relationships between organic matter quality and bacteria, fungi and microarthropods in litter and soil.

Materials and methods

Litters and soils from 24 sites were analysed for the abiotic (pH, water content, total C and N content and the chemical composition of soluble C: carbohydrate, alkyl, O-alkyl, aromatic and carboxyl groups) and the biotic characteristics (bacterial and fungal abundances, urease and β-glucosidase, microbial respiration, microarthropod community).

Results

Litter had a high carbohydrate and low C contents, whereas soil had higher content of recalcitrant compounds (aromatic and carboxylic groups) and C. Whitin substrate types, higher C content was found in litter from shrubs and in soil under sclerophyllous evergreens. Bacterial abundances were lower in litter than in soil, whereas microbial respiration, enzymatic activities, microarthropod densities and predator abundances were higher in litter than in soil. Microbial abundances and activities were strongly related to total C and N concentrations in both litter and soil, while the microarthropod community was positively correlated with soluble C recalcitrant compounds in soil.

Conclusions

Soils showed a high capacity for C accumulation due to the high content of recalcitrant compounds. In soil, the microarthropod community, more than bacteria and fungi, was positively correlated with the quality of organic matter.

中文翻译：

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检查地中海地区凋落物和土壤特征对分解者群落、食碎物和碳积累的影响

背景和目的

凋落物和土壤特征影响分解者和食碎物的丰度和活动，从而影响碳积累。土壤有机质的化学成分与土壤生物之间的关系尚不清楚。本研究旨在探讨凋落物和土壤有机质的质量和数量如何影响碳积累以及有机质质量与凋落物和土壤中细菌、真菌和微节肢动物的关系。

材料和方法

对 24 个地点的凋落物和土壤进行了非生物特征（pH、含水量、总碳和氮含量以及可溶性碳的化学成分：碳水化合物、烷基、O-烷基、芳香族和羧基）和生物特征（细菌和微生物）的分析。真菌丰度、脲酶和β-葡萄糖苷酶、微生物呼吸、微节肢动物群落）。

结果

凋落物碳水化合物含量高，碳含量低，而土壤中顽固化合物（芳香族和羧基）和碳含量较高。在白色基质类型中，灌木凋落物和硬叶常绿植物下的土壤中碳含量较高。枯落物中的细菌丰度低于土壤中，而枯落物中的微生物呼吸、酶活性、微型节肢动物密度和捕食者丰度则高于土壤中。微生物丰度和活性与凋落物和土壤中的总碳和总氮浓度密切相关，而微型节肢动物群落与土壤中可溶性碳顽抗化合物呈正相关。

结论

由于顽固化合物含量高，土壤显示出高碳积累能力。在土壤中，微型节肢动物群落比细菌和真菌更与有机质质量呈正相关。