Elemental stoichiometry and Rock-Eval<span style="position:relative; bottom:0.5em; " class="text">®</span> thermal stability of organic matter in French topsoils
<p>The quality and quantity of soil organic matter (SOM) are key elements that impact soil health and climate regulation by soils. The Rock-Eval<sup>®</sup> thermal analysis technique is becoming more commonly used, as it represents a powerful method for SOM characterization by pro...
| Main Authors: | , , , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2023-05-01
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| Series: | SOIL |
| Online Access: | https://soil.copernicus.org/articles/9/209/2023/soil-9-209-2023.pdf |
| Summary: | <p>The quality and quantity of soil organic matter (SOM) are
key elements that impact soil health and climate regulation by soils. The
Rock-Eval<sup>®</sup> thermal analysis technique is becoming more commonly used, as
it represents a powerful method for SOM characterization by providing
insights into bulk SOM chemistry and thermal stability. In this study, we
applied this technique on a large soil sample set from the first campaign
(2000–2009) of the French Soil Quality Monitoring Network (RMQS – Réseau de mesures de la qualité des sols). Based on
our analyses of ca. 2000 composite surface (0–30 cm) samples collected across
mainland France, we observed a significant impact of land cover on both the SOM
thermal stability and elemental stoichiometry. Cropland soils had a lower
mean hydrogen index value (a proxy for the SOM <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M1" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><mi mathvariant="normal">H</mi><mo>/</mo><mi mathvariant="normal">C</mi></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="24pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="b404a1b9e7aed8e410134b3c12f580ee"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="soil-9-209-2023-ie00001.svg" width="24pt" height="14pt" src="soil-9-209-2023-ie00001.png"/></svg:svg></span></span> ratio) and a higher
thermal stability than grasslands and forests. Regarding the oxygen index (a
proxy for the SOM <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M2" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><mi mathvariant="normal">O</mi><mo>/</mo><mi mathvariant="normal">C</mi></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="25pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="aa3ee63d16a9544135a7a9f6ec90028c"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="soil-9-209-2023-ie00002.svg" width="25pt" height="14pt" src="soil-9-209-2023-ie00002.png"/></svg:svg></span></span> ratio), we observed significant differences among the values for
croplands, grasslands, and forests. Positive correlations of the
temperature parameters with the clay content and pH highlight the protective effect of clay on organic matter as well as the
impact of pH on microorganisms' mineralization activity. Surprisingly, we
found weak effects of climatic parameters on the thermal stability and
stoichiometry of SOM. Our data suggest that topsoil SOM is on average more
oxidized and biogeochemically stable in croplands. More generally, the high
number and even distribution of data across the whole French territory allow one to
build a national interpretative reference for these indicators in surface
soils.</p> |
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| ISSN: | 2199-3971 2199-398X |