Abstract

Soil micromorphology, by means of the description and analysis of soil thin sections, provides information about soil microstructure, which includes, among other features, morphological data on the aggregates and the porosity derived from structure formation. Soil porosity may be due to both abiotic factors and biological activity (biopores). The aim of this study is to validate a methodology for the quantification of bioporosity in thin sections of Luvic Phaeozems of Argentina, for its use as soil quality indicator. Soil samples were taken from the surface horizon in plots with different uses: reserve (R), agricultural (A), Eucalyptus globulus forest plantation (E), and Pinus radiata forest plantation (P). In each site, bulk density, penetration resistance, structural stability, organic matter, and pH were determined. Three undisturbed samples were taken, impregnated with resin, and treated using routine techniques to obtain soil thin sections. Volume percentages of total porosity and biopores were determined in the thin sections using two methodologies (I: irregular polygon on the outline of the biopore and II point counting), in order to obtain an estimation of the biological activity under the different land uses. Plots R, E, and P showed greater porosity and higher bioturbation compared to plot A. In addition, the percentage of biopores in soils of R, E, and P plots reaches almost 80% of the total porosity, while in soil of plot A plot, it is two times lower (40%). This indicates greater biological activity in the natural and forested plots as compared with the cultivated plot. This activity is linked to the high content of organic matter, high structural stability, low bulk density, and low penetration resistance. These results show that the estimation of the bioturbated volume would be a good indicator of soil quality and, in addition, the methodologies used in this study constitute an easy-to-use tool for the determination of bioporosity in soil. However, methodology II is preferred, because it requires a shorter time of image edition.

中文翻译：

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阿根廷布宜诺斯艾利斯东南部Luvic Phaeozems薄片中的生物孔隙度及其作为土壤质量指标的可能作用。微观形态学方法

摘要

通过对土壤薄片的描述和分析，土壤微形态学提供了有关土壤微结构的信息，除其他特征外，还包括有关聚集体的形态学数据和从结构形成中得出的孔隙度。土壤孔隙度可能是由于非生物因素和生物活性（生物孔）引起的。这项研究的目的是验证一种用于量化阿根廷Luvic Phaeozems薄片中生物孔隙度的方法，以用作土壤质量指标。在不同用途的地块中从地表水平采集土壤样品：保护区（R），农业（A），球状桉树人工林（E）和辐射松人工林（P）。在每个位置，测定堆密度，抗穿透性，结构稳定性，有机物和pH。取三个未受干扰的样品，用树脂浸渍，并使用常规技术进行处理以获得土壤薄片。使用两种方法在薄片中确定总孔隙率和生物孔隙的体积百分比（I ：生物孔隙轮廓上的不规则多边形和II点计数），以估算不同土地利用下的生物活性。与图A相比，图R，E和P表现出更高的孔隙率和更高的生物扰动。此外，R，E和P图的土壤中的生物孔百分比几乎达到总孔隙率的80％，而在图A的土壤中情节，它低了两倍（40％）。这表明与耕地相比，自然和森林地带的生物活性更高。这种活性与高含量的有机物，高结构稳定性，低堆积密度和低抗穿透性有关。这些结果表明，对生物扰动量的估算将是土壤质量的良好指标，此外，本研究中使用的方法学构成确定土壤中生物孔隙度的易于使用的工具。但是，方法II是首选方法，因为它需要更短的图像编辑时间。