The role of organic materials and calcium carbonates mediated by biocrusts in altering soil aggregate size fractions in drylands

IF 5.4 1区农林科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY

Catena Pub Date : 2024-10-30 DOI:10.1016/j.catena.2024.108482

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引用次数: 0

Abstract

Biological soil crusts (biocrusts) play a critical role in influencing soil biogeochemical properties and soil aggregate formation. While the effect of biocrusts on soil aggregate formation is well-established, the precise impact of biocrusts on specific aggregate size distribution (ASD) fractions, particularly in drylands, still requires conclusive determination. This study focused on the impact of biocrusts on organic material (OM) and calcium carbonate (CC) content in topsoil aggregates within the Sejzi Plain, Iran. Samples were collected from areas with and without biocrust coverage using a stratified random sampling method, and various soil properties were analyzed and compared. The study quantified OM and CC levels, assessed particle size distribution (PSD) through laser diffraction analysis, and compared aggregate size distribution (ASD). Scanning electron microscopy (SEM) observations revealed the presence of extracellular polymer substances (EPSs) in soils covered by biocrusts. High-performance liquid chromatography (HPLC) identified monosaccharides like glucose, arabinose, mannose, and xylose as components of the EPS polysaccharidic fraction. The ratio of hexose to pentose, calculated to be 2.41 in biocrust-covered soils, suggested the role of biocrusts in secreting EPSs into the soil. The results showed that the removal of CC and OM led to an increase in particle size in very fine sands, fine silts, and very fine silts, while aggregate size decreased in coarse sands in biocrust-covered soils. Soils lacking biocrusts exhibited minimal changes except in very coarse sands. In summary, the CC and OM produced by biocrusts enhance soil particle adhesion in fine silt and very fine sand fractions, contributing to the formation of coarse sand and very coarse sand aggregates.

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以生物簇为媒介的有机物和碳酸钙在改变旱地土壤团聚体大小方面的作用

土壤生物结壳（生物结壳）在影响土壤生物地球化学特性和土壤团聚体形成方面起着至关重要的作用。虽然生物结壳对土壤团聚体形成的影响已得到证实，但生物结壳对特定团聚体粒度分布（ASD）组分的确切影响，尤其是在干旱地区，仍有待最终确定。本研究的重点是生物簇对伊朗塞吉兹平原表层土壤团聚体中有机物（OM）和碳酸钙（CC）含量的影响。采用分层随机取样法，从有生物簇覆盖和无生物簇覆盖的地区采集了样本，并对各种土壤特性进行了分析和比较。该研究量化了 OM 和 CC 含量，通过激光衍射分析评估了粒度分布（PSD），并比较了集料粒度分布（ASD）。扫描电子显微镜（SEM）观察发现，被生物簇覆盖的土壤中存在胞外聚合物物质（EPSs）。高效液相色谱法（HPLC）鉴定出葡萄糖、阿拉伯糖、甘露糖和木糖等单糖是 EPS 多糖部分的成分。经计算，在生物簇覆盖的土壤中，己糖与戊糖的比例为 2.41，这表明生物簇在向土壤中分泌 EPS 方面发挥了作用。结果表明，在生物簇覆盖的土壤中，CC 和 OM 的去除导致极细砂、细淤泥和极细淤泥的粒径增大，而粗砂的集料粒径减小。除极粗砂外，缺乏生物簇的土壤变化极小。总之，生物簇产生的 CC 和 OM 增强了细粉砂和极细砂部分的土壤颗粒粘附力，有助于形成粗砂和极粗砂聚合体。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Catena 环境科学-地球科学综合

CiteScore

10.50

自引率

9.70%

发文量

816

审稿时长

54 days

期刊介绍： Catena publishes papers describing original field and laboratory investigations and reviews on geoecology and landscape evolution with emphasis on interdisciplinary aspects of soil science, hydrology and geomorphology. It aims to disseminate new knowledge and foster better understanding of the physical environment, of evolutionary sequences that have resulted in past and current landscapes, and of the natural processes that are likely to determine the fate of our terrestrial environment. Papers within any one of the above topics are welcome provided they are of sufficiently wide interest and relevance.