EGU23-17196
https://doi.org/10.5194/egusphere-egu23-17196
EGU General Assembly 2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

Capability of selected indicators for soil organic carbon stability to predict soil functions

Guusje Koorneef1,2, Ron de Goede2, Sophie van Rijssel3, Mirjam Pulleman2,4, and Rob Comans1
Guusje Koorneef et al.
  • 1Soil Chemistry and Chemical Soil Quality, Wageningen University and Research, P.O.Box 47, 6700AA Wageningen, The Netherlands
  • 2Soil Biology Group, Wageningen University and Research, P.O.Box 47, 6700AA Wageningen, The Netherlands
  • 3Department of Terrestrial Ecology; Netherlands Institute for Ecology (NIOO-KNAW), PO box 50, 6700 AB 12 Wageningen, The Netherlands
  • 4International Centre for Tropical Agriculture (CIAT), 763537 Cali, Colombia

Soil organic carbon (OC) is pivotal for soil functioning, especially in the domains of elemental cycling, disease control and the regulation of soil structure and water. High OC contents are generally associated with improved soil functioning, and therefore OC content is widely used as a soil health indicator. The stability of OC influences all functions that depend on microbial decomposition (e.g. nutrient provisioning) or carbon retention (e.g. C sequestration). Yet, a standardized indicator for OC stability that can be used in soil health assessments is still in development. Here, we investigate to what extent selected OC stability indicators can predict soil functioning, and which type of OC stability indicator improves predictions most as an additional measurement besides OC content.

We collected soil samples from arable fields in the Netherlands on marine clay (n=144) and sand (n=81) soils. For each soil sample, 18 different soil function measurements were performed and grouped into 3 function domains (i.e. elemental cycling, disease control, and the regulation of soil structure and water). In addition, 21 OC stability indicators were analyzed and grouped into 4 types of OC stability indicators (i.e. carbon pools; carbon fractions, thermal stability indicators, and indicators based on elemental ratio). Multiple linear regression was used to determine how much of the variation in each soil function measurement could be predicted by the OC stability indicators and other measured intrinsic soil properties (e.g. texture and pH).

We found that OC stability and intrinsic soil properties could significantly predict soil functions better in the domain of regulation of soil structure and water (R2adj=40±18%) than in the other 2 function domains (elemental cycling: R2adj =32±31%; disease control: R2adj =22±11%). OC stability indicators could predict 80±26% of this maximum explainable variation, averaged over all soil functions (clay: 82±18%; sand: 77±32%). This percentage did not differ significantly between the function domains. A regression model with only total OC content explained 18±21% of the maximum explainable variation (clay:23±26%; sand:14±14%). The addition of 1 OC stability indicator increased this percentage to 49±23% (clay: 58±20%; sand: 39±22%). Predictions of soil functioning were most strongly improved by including a thermal stability indicator in addition to total OC content.

We conclude that OC stability indicators can predict soil functioning adequately and that thermal stability indicators show particular potential as OC stability indicator in soil health assessments.

How to cite: Koorneef, G., de Goede, R., van Rijssel, S., Pulleman, M., and Comans, R.: Capability of selected indicators for soil organic carbon stability to predict soil functions, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-17196, https://doi.org/10.5194/egusphere-egu23-17196, 2023.