Historical charcoal additions potentially improve stability of soil organic carbon due to altered particulate carbon fractions

Citation:
Historical charcoal additions potentially improve stability of soil organic carbon due to altered particulate carbon fractions, HOFMANN, Diana, Steffen Bernhard, Abdelrahman Hamada, Disko Ulrich, and Borchard Nils , The 18th Conference of the International Humic Substances Society, , Kanazawa, Japan, (2016) copy at www.tinyurl.com/zw9j6hz

Improving the stability of soil organic carbon (SOC) and soil’s capacity to store SOC are promising ways to mitigate climate change. Recently, several studies showed that additions of charred biomass (e.g. charcoal) elevated SOC stocks and stabilized natural organic matter; however, the mechanisms for C stabilization are hardly known. The SOC, dissolved organic matter (DOM) and particulate organic matter (POM) from two different soils and their counterparts with former inputs of charcoal by means of elemental analysis. Further, hot water extracts (HWE) of soils and applied charcoal were investigated by the ESI-FTICR-MS for molecular level details of thousands of inherent organic compounds Charcoal additions increased substantially concentrations of black C, total C and total N in bulk soil, however, concentration of water extractable SOC and N remained unchanged. Pattern of the POM size fractions changed with a relative increase in the free POM fraction and a decrease in the occluded POM fraction and soil particles <20 μm. However, all POM fractions in charcoal enriched soils were augmented with C and N This study confirmed previous findings that charcoal additions increase SOC long-lastingly. Further, an assumed abrasion resistance of charcoal particles may explain the elevated free POM fractions, which thereby may act as sorbent of soil organic matter. This in turn will potentially stabilize SOC and increase soil’s carbon saturation capacity.

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