文章摘要
用计算机模型验证土壤有机碳周转负反馈作用现象与机理
Validation of Negative Feedback in Soil Organic Carbon Dynamics and its underlying mechanisms using Computer Model
投稿时间:2018-09-29  修订日期:2018-11-07
DOI:
中文关键词: 有机碳  有机碳饱和值  负反馈作用  模型
英文关键词: SOC  SOC saturation  Negative feedback  Model
基金项目:中国农业科学院科技创新工程协同创新任务(CAAS-XTCX2016015)资助
作者单位邮编
王瑞琪 天津农学院农学与资源环境学院 300191
蔡媛媛 天津农学院农学与资源环境学院 
王丽丽 农业部环境保护科研监测所 
杨殿林 农业部环境保护科研监测所 
刘惠芬 天津农学院农学与资源环境学院 
谭炳昌* 农业部环境保护科研监测所 300191
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中文摘要:
      有机物料腐殖化系数(h)与有机碳降解系数(k)是控制土壤有机碳周转过程的两个关键参数,研究该两参数对于了解土壤有机碳周转过程至关重要。过去大量的工作研究土壤水热等条件对该两参数的影响,但关于有机碳含量如何影响该两参数以及有机碳含量的作用机理还鲜有报道。本研究用计算机模型探讨该有机碳含量对自身周转作用的影响以及相应的机理。结果显示:有机碳含量的动态变化不能反映有机碳含量是否对自身周转造成影响,但有机碳含量与碳输入水平的关系可以反映有机碳含量的作用,即(1)不管该两参数是否与有机碳含量有关,有机碳含量均随着时间延长而渐近线增加或降低至平衡值;(2)当假设两参数与有机碳含量无关,则有机碳含量随碳输入水平增加呈直线增加;但当假设有机碳含量通过有机碳周转负反馈作用影响该两参数,即h随有机碳含量增加而降低,而且k同时增加,则有机碳含量随碳输入水平增加而渐近线增加。进一步验证该负反馈作用机理分析也发现当考虑负反馈作用的机理时,有机碳含量随着碳输入水平增加而渐近线增加。因此有机碳周转负反馈作用合理,有必要在计算机模型构建中考虑该影响因素,并且考虑该因素也是可行的。
英文摘要:
      Humification coefficient of input organic material (h) and decomposition rate (k) of soil organic carbon (SOC) are two key parameters that control the SOC turnover processes. A lot of previous studies have investigated how elements such as water and temperature can affect these processes, but how SOC content affect its own turnover processes is seldom concerned. We developed computer models to test the effect of SOC content on the SOC turnover processes and its underlying mechanisms. The results showed that (1) however h and k would change with SOC content, SOC content changed asymptotically with time, and reached equilibrium finally; (2) when assuming these two parameters were constant with SOC content, SOC content would linearly increase without limit with C i-nput level; SOC content would increase asymptotically with C input level when considering h decreased with SOC content and k increased at the same time, an asymptotic relationship between SOC content and C input level will occur. The change in h and k with SOC content is termed as negative feedback of SOC turnover. Further study into the mechanisms underlying the negative feedback supported the asymptotic relationship between SOC content and C input level. We suggest that the negative feedback of SOC turnover is reasonable, and it is necessary and possible to consider this effect in model developing.
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