Details zur Publikation

Kategorie Textpublikation
Referenztyp Zeitschriften
DOI 10.1016/j.geoderma.2023.116472
Lizenz creative commons licence
Titel (primär) Soil organic carbon sequestration in agricultural long-term field experiments as derived from particulate and mineral-associated organic matter
Autor Just, C.; Armbruster, M.; Barkusky, D.; Baumecker, M.; Diepolder, M.; Döring, T.F.; Heigl, L.; Honermeier, B.; Jate, M.; Merbach, I.; Rusch, C.; Schubert, D.; Schulz, F.; Schweitzer, K.; Seidel, S.; Sommer, M.; Spiegel, H.; Thumm, U.; Urbatzka, P.; Zimmer, J.; Kögel-Knabner, I.; Wiesmeier, M.
Journal / Serie Geoderma
Erscheinungsjahr 2023
Department BZF
Band/Volume 434
Seite von art. 116472
Sprache englisch
Topic T5 Future Landscapes
Keywords Fractionation; Mixed-effects modeling; Fertilization; Crop rotation; POM-C / MAOM-C ratio indicator
Abstract Soil organic matter (SOM) is indispensable for soil health and, in the context of climate change, is considered a significant CO2 sink. Improving agricultural management to increase long-term soil organic carbon (SOC) stocks for mitigating climate change requires tools that estimate short and long-cycling SOM pools. In this study, we analyzed changes in fast-cycling particulate organic matter (POM) and slow-cycling mineral-associated organic matter (MAOM) induced by common management practices, i.e., fertilization and crop rotation in topsoils from 25 Central European long-term field experiments. When relating MAOM-C contents to recent MAOM-C saturation levels, estimated sequestration potentials were only met in coarse-textured soils under appropriate agricultural management or fine-textured soils under extreme organic fertilization. Soil texture, organic fertilization, and below-ground OC inputs through root exudates and root biomass were decisive for estimating MAOM-C, allowing for calibration of a mixed-effects model (Nakagawa’s: marginal R2m = 0.6, conditional R2c = 0.89). While the models containing soil texture and organic fertilization parameters can be validated and generalized (R2 = 0.43), the below-ground OC input predictor substantially decreases the generalizability of the validated models (R2 = 0.14). According to quantile regression models, we estimate the average difference in MAOM-C concentration between well-managed and control site (without organic fertilization) topsoils to 4.1 mg g−1 soil. In dependence on the soil bulk density, this amounts to 1.38 – 1.84 t ha−1 MAOM-C stocks or 5.06 – 10.1 t ha−1 CO2-equivalents. POM-C was difficult to predict (R2 = 0.28), presumably due to strong POM dynamics. The POM-C / MAOM-C ratio can inform on the effects of agricultural practices in before/after management change comparisons. Under increasing SOC concentration, an increasing POM-C / MAOM-C ratio indicates that the effects of organic fertilization do not transfer to real effects on long-term SOC sequestration. Because MAOM-C depends on soil texture, this ratio is also a covariate of soil texture, limiting it for comparisons between sites with different textures. However, our data indicate that agricultural long-term field experiment soils constantly approximate MAOM-C saturation when the POM-C/MAOM-C ratio is >0.35. This ratio might be used as a management goal to prevent organic over-fertilization and N loss, especially on coarse-textured soils. Thereby, the POM-C / MAOM-C ratio can help to optimize SOC management and sequestration on agricultural soils and support climate change mitigation strategies in Central Europe.
dauerhafte UFZ-Verlinkung
Just, C., Armbruster, M., Barkusky, D., Baumecker, M., Diepolder, M., Döring, T.F., Heigl, L., Honermeier, B., Jate, M., Merbach, I., Rusch, C., Schubert, D., Schulz, F., Schweitzer, K., Seidel, S., Sommer, M., Spiegel, H., Thumm, U., Urbatzka, P., Zimmer, J., Kögel-Knabner, I., Wiesmeier, M. (2023):
Soil organic carbon sequestration in agricultural long-term field experiments as derived from particulate and mineral-associated organic matter
Geoderma 434 , art. 116472