Relevance and limitations of biogenic and physicogenic classification: a comparison of approaches for differentiating the origin of soil aggregates

Although freshly formed or unaltered biogenic aggregates are easily recognized, identifying the origin of aggregates altered by physical and biological processes remains empirical and prone to error. The aim of this study was to distinguish between biogenic (BIO) and physicogenic (PHYS) aggregates i...

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Autores principales: Jouquet, Pascal, Zangerle, A., Rumpel, C., Brunet, D., Bottinelli, N., Tran Duc Toan
Formato: Journal Article
Lenguaje:Inglés
Publicado: Wiley 2009
Materias:
Acceso en línea:https://hdl.handle.net/10568/40616
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author Jouquet, Pascal
Zangerle, A.
Rumpel, C.
Brunet, D.
Bottinelli, N.
Tran Duc Toan
author_browse Bottinelli, N.
Brunet, D.
Jouquet, Pascal
Rumpel, C.
Tran Duc Toan
Zangerle, A.
author_facet Jouquet, Pascal
Zangerle, A.
Rumpel, C.
Brunet, D.
Bottinelli, N.
Tran Duc Toan
author_sort Jouquet, Pascal
collection Repository of Agricultural Research Outputs (CGSpace)
description Although freshly formed or unaltered biogenic aggregates are easily recognized, identifying the origin of aggregates altered by physical and biological processes remains empirical and prone to error. The aim of this study was to distinguish between biogenic (BIO) and physicogenic (PHYS) aggregates in various states of fragmentation or size classes using visual, physical and chemical characteristics. Casts produced by Amynthas khami (BIO) and surrounding soil aggregates without visible biological activity (PHYS) were left to disaggregate by natural rainfall events and then separated into five size classes of >10, 10-5, 5-2, 2-0.5 and <0.5 mm. We then analysed aggregate morphology, elemental and stable isotope composition and soil stability, and used near-infrared spectroscopy (NIRS) to determine their chemical characteristics. Although visual assessment is the method most commonly used in the field to distinguish between BIO and PHYS, our study found that the results obtained were always prone to error and that the classification was arbitrary for BIO and PHYS aggregates smaller than 5 and 2 mm in size, respectively. Soil structural stability was only useful for identifying BIO aggregates larger than 2 mm. While C content and d13C in BIO were always different from PHYS, regardless of soil aggregate size, N content and d15N were similar. NIRS was the most effective method because it clearly discriminated soil aggregates on the basis of size and origin. The NIRS characteristics of BIO were also more uniform than those of PHYS, suggesting that BIO aggregates have a simpler organization and as a consequence more homogeneous ecological functions. Thus, our findings suggest that information may be lost when only the physical aspect of aggregates is used to quantify the activity of ecosystem engineers in soil. After fragmentation, BIO aggregates become hidden and although it may be impossible to distinguish them visually from PHYS aggregates they retain some of their specific chemical characteristics.
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spelling CGSpace406162024-11-19T09:23:41Z Relevance and limitations of biogenic and physicogenic classification: a comparison of approaches for differentiating the origin of soil aggregates Jouquet, Pascal Zangerle, A. Rumpel, C. Brunet, D. Bottinelli, N. Tran Duc Toan soil analysis biogenic amines earthworms soil structural units soil organic matter nutrient cycling in ecosystems soil structure Although freshly formed or unaltered biogenic aggregates are easily recognized, identifying the origin of aggregates altered by physical and biological processes remains empirical and prone to error. The aim of this study was to distinguish between biogenic (BIO) and physicogenic (PHYS) aggregates in various states of fragmentation or size classes using visual, physical and chemical characteristics. Casts produced by Amynthas khami (BIO) and surrounding soil aggregates without visible biological activity (PHYS) were left to disaggregate by natural rainfall events and then separated into five size classes of >10, 10-5, 5-2, 2-0.5 and <0.5 mm. We then analysed aggregate morphology, elemental and stable isotope composition and soil stability, and used near-infrared spectroscopy (NIRS) to determine their chemical characteristics. Although visual assessment is the method most commonly used in the field to distinguish between BIO and PHYS, our study found that the results obtained were always prone to error and that the classification was arbitrary for BIO and PHYS aggregates smaller than 5 and 2 mm in size, respectively. Soil structural stability was only useful for identifying BIO aggregates larger than 2 mm. While C content and d13C in BIO were always different from PHYS, regardless of soil aggregate size, N content and d15N were similar. NIRS was the most effective method because it clearly discriminated soil aggregates on the basis of size and origin. The NIRS characteristics of BIO were also more uniform than those of PHYS, suggesting that BIO aggregates have a simpler organization and as a consequence more homogeneous ecological functions. Thus, our findings suggest that information may be lost when only the physical aspect of aggregates is used to quantify the activity of ecosystem engineers in soil. After fragmentation, BIO aggregates become hidden and although it may be impossible to distinguish them visually from PHYS aggregates they retain some of their specific chemical characteristics. 2009-12 2014-06-13T14:48:02Z 2014-06-13T14:48:02Z Journal Article https://hdl.handle.net/10568/40616 en Limited Access Wiley Jouquet, Pascal; Zangerle, A.; Rumpel, C.; Brunet, D.; Bottinelli, N.; Toan, Tran Duc. 2009. Relevance and limitations of biogenic and physicogenic classification: a comparison of approaches for differentiating the origin of soil aggregates. European Journal of Soil Science, 60(6): 1117-1125. doi: https://doi.org/10.1111/j.1365-2389.2009.01168.x
spellingShingle soil analysis
biogenic amines
earthworms
soil structural units
soil organic matter
nutrient cycling in ecosystems
soil structure
Jouquet, Pascal
Zangerle, A.
Rumpel, C.
Brunet, D.
Bottinelli, N.
Tran Duc Toan
Relevance and limitations of biogenic and physicogenic classification: a comparison of approaches for differentiating the origin of soil aggregates
title Relevance and limitations of biogenic and physicogenic classification: a comparison of approaches for differentiating the origin of soil aggregates
title_full Relevance and limitations of biogenic and physicogenic classification: a comparison of approaches for differentiating the origin of soil aggregates
title_fullStr Relevance and limitations of biogenic and physicogenic classification: a comparison of approaches for differentiating the origin of soil aggregates
title_full_unstemmed Relevance and limitations of biogenic and physicogenic classification: a comparison of approaches for differentiating the origin of soil aggregates
title_short Relevance and limitations of biogenic and physicogenic classification: a comparison of approaches for differentiating the origin of soil aggregates
title_sort relevance and limitations of biogenic and physicogenic classification a comparison of approaches for differentiating the origin of soil aggregates
topic soil analysis
biogenic amines
earthworms
soil structural units
soil organic matter
nutrient cycling in ecosystems
soil structure
url https://hdl.handle.net/10568/40616
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