Abstract

The relative importance of various soil mineral constituents (e.g. clay-sized particles, aluminum- and iron-bearing mineral reactive phases) in protecting soil organic carbon (SOC) from decomposition is not yet fully understood in arable soils formed from quaternary deposits in humid continental climates. In this study, we investigated the relationships between soil physico-chemical properties (i.e. contents of oxalate-extractable aluminum (Alox) and iron (Feox) and clay size particle < 2 mu m), grain yield (as a proxy for carbon input) and total SOC as well as SOC in different soil fractions for samples taken from the topsoil of an arable field at Bjertorp in south-west Sweden. We found a positive correlation between Alox and total SOC content, where Alox explained ca. 48% of the spatial variation in SOC. We also found that ca. 80% of SOC was stored in silt- and claysized (SC) fractions, where Al-bearing reactive mineral phases (estimated by Alox) may be important for organicmineral associations and clay aggregation. Our results were supported by data collated from the literature for arable topsoil in similar climates, which also showed positive correlations between SOC and Alox contents (R-2 = 23.1 - 74.5%). Multiple linear regression showed that including spatially-variable crop yields as a proxy for carbon inputs improved the prediction of SOC variation across the Bjertorp field. Other unquantified soil properties such as exchangeable calcium may account for the remaining unexplained variation in topsoil SOC. We conclude that Al-bearing reactive mineral phases are more important than clay content and Fe-bearing reactive mineral phases for SOC stabilization in arable topsoil in humid continental climates.

Keywords

Soil organic carbon; Oxalate-extractable aluminum; Clay; Arable soil; Fractionation; Carbon input

Published in

Geoderma
2021, Volume: 402, article number: 115345
Publisher: ELSEVIER

SLU Authors

• Fukumasu, Jumpei

  • Department of Soil and Environment, Swedish University of Agricultural Sciences
    

• Coucheney, Elsa

  • Department of Soil and Environment, Swedish University of Agricultural Sciences
    

• Jarvis, Nicholas

  • Department of Soil and Environment, Swedish University of Agricultural Sciences
    

• Klöffel, Tobias

  • Department of Soil and Environment, Swedish University of Agricultural Sciences
    

• Koestel, Johannes

  • Department of Soil and Environment, Swedish University of Agricultural Sciences
    
  • Agroscope

• Kätterer, Thomas

  • Department of Ecology, Swedish University of Agricultural Sciences
    

• Nimblad Svensson, David

  • Department of Soil and Environment, Swedish University of Agricultural Sciences
    

• Wetterlind, Johanna

  • Department of Soil and Environment, Swedish University of Agricultural Sciences
    

• Larsbo, Mats

  • Department of Soil and Environment, Swedish University of Agricultural Sciences
    

Sustainable Development Goals

Protect, restore and promote sustainable use of terrestrial ecosystems, sustainably manage forests, combat desertification, and halt and reverse land degradation and halt biodiversity loss


UKÄ Subject classification

Soil Science


Publication identifier

DOI: https://doi.org/10.1016/j.geoderma.2021.115345

Permanent link to this page (URI)

https://res.slu.se/id/publ/113466