Soils to act as both sink and source of CO2. Soil organic carbon can be stabilized in soil by a number mechanisms like aggregation (macro- and micro- ), physicochemical stabilization of SOC is due to the sorption of SOC compounds on silt plus clay surfaces or mineral colloids, and recalcitrant plant parts or man-made recalcitrant organic materials like biochar. Aggregation mechanism seems be one of the widely accepted mechanisms from the soil management prospective because conservation tillage is commonly promoted. What is the known proportion of these mechanisms on any level (landscape, regional, national or global). Understanding of this proportion would be a useful indicator for land users or managers intending to conserve soil carbon. Kindly provide relevant literature and expertise on this please.
Dear Prof. Y. Bajgai,
I am sharing two related research articles for you.
Thank you
Soil organic carbon maintain soil fertility status and increase microbial growth.
@ Dr B. K. Mondal, thank you for your respons and for sharing the related documents. However, a document that compares the soil organic carbon mechanisms would be useful. Best regards.
@ Kshirod Sahoo, you are right that the SOC is integral part of soil fertility and to support the life soil microbes. But a document that compares the soil organic carbon mechanisms would be valuable in understanding of proportion of SOC stabilization mechanism like aggregation, physicochemical or the inertness characteristics. Best wishes
This is a very good question. There will be no concrete answer for today. All the mechanisms you have listed for the stabilization of organic carbon in the soil, in turn, depend on many factors. Therefore, in each specific case, it is necessary to take into account the real situation (quality and quantity of the mineral part, soil acidity, the content of aluminum and iron, the level of active organic matter (POM) and other factors. Probably, the most successful answer to your question will be a publication Francisco J. Matus. Fine silt and clay content is the main factor defining maximal C and N accumulations in soils: a meta‑analysis. Scientific Reports | (2021) 11:6438 | https://doi.org/10.1038/s41598-021-84821-6.
Wish you success !
@ Zenon Hamkalo, thank you for your response and the relevant literature. The literature provides information on role the silt and clay content of the soil in determining the the SOC level in upper profile of a soil. This is due to the physicochemical stabilization mechanism as a result of sorption of SOC compounds on silt plus clay surfaces or mineral colloid. However, aggregation model of SOC stabilization is the result of physical barrier being formed to make soil microbes or oxygen supply less accessible. When the microbes do not have access they cannot mineralize the SOM to reduce the CO2 emission. While the recalcitrant organic materials like biochar cannot be easily decomposed by the microbes. Thank you so much for your valuable response and literature. Best wishes
@ Kshirod Sahoo, thank you again for related information. The literature source you have provided deals with 'Soil organic carbon (SOC) is one of the most important characteristics of soils that result from the interplay of net primary producers, decomposers, and mineralogy' which is useful, information on the proportions of the SOC stabilization mechanisms would be more beneficial to this discussion. The physicochemical stabilization mechanism as a result of sorption of SOC compounds on silt plus clay surfaces or mineral colloid. However, aggregation model of SOC stabilization is the result of physical barrier being formed to make soil microbes or oxygen supply less accessible. When the microbes do not have access they cannot mineralize the SOM to reduce the CO2 emission. While the recalcitrant organic materials like biochar cannot be easily decomposed by the microbes. It would be useful to get information on the above stabilization mechanisms and their relative proportion at any level like farm level or landscape or such like. Best wishes
Dear Yadunath-Bajgai, regarding the role of the mechanism of physical stabilization (soil aggregation), this publication may be useful.Article A coupled carbon, aggregation, and structure turnover (CAST)...
In general, the role of aggregates in the stabilization of soil organic matter has been insufficiently studied in comparison with organo-mineral interactions.
Good luck.
Thank you very much Zenon Hamkalo for your insight and for attaching the very useful article. Yes, You are right the role of aggregates in the stabilization of soil organic matter has been insufficiently studied in comparison with organo-mineral interactions. Therefore there is need to further study the aggregation model more.
Many thanks and best regards
If interaction processes of carbon with soil are already studied, then such proportions can be obtained as a result of modeling.
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