Validation of the Phenomenon and Mechanisms of Negative Feedback in Soil Organic Carbon Turnover Using Computer Models
Keywords:
Soil organic carbon, Saturation, Humification, Decomposition, Turnover process, Negative feedback, Computer modelAbstract
The humification coefficient of input organic material (h) and the decomposition rate (k) of soil organic carbon (SOC) are two crucial parameters that govern the SOC turnover processes. Numerous prior studies have examined how factors like water and temperature can influence these processes, but the impact of SOC content on its own turnover processes has received limited attention. We have developed computer models to investigate the effect of SOC content on SOC turnover processes and the underlying mechanisms. The findings indicate that regardless of changes in h and k, the SOC content also varies asymptotically over time, ultimately reaching an equilibrium state. Assuming that these two parameters remain constant with respect to SOC content, the SOC content would increase linearly without any limitation from the C input level. However, when considering that h decreases with SOC content and k increases simultaneously, the SOC content would increase asymptotically with the C input level. This suggests an asymptotic relationship between SOC content and C input level. The variations in h and k with SOC content are referred to as negative feedback in SOC turnover. Further examination of the mechanisms behind this negative feedback supports the asymptotic relationship between SOC content and C input level. We propose that the concept of negative feedback in SOC turnover is valid and that it is both necessary and feasible to incorporate this effect into model development.
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