Measuring and modeling continuous quality distributions of soil organic matter

[摘要] An understanding of the dynamics of soil organic matter (SOM) is importantfor our ability to develop management practices that preserve soil qualityand sequester carbon. Most SOM decomposition models represent theheterogeneity of organic matter by a few discrete compartments withdifferent turnover rates, while other models employ a continuous qualitydistribution. To make the multi-compartment models more mechanistic innature, it has been argued that the compartments should be related to soilfractions actually occurring and having a functional role in the soil. Inthis paper, we make the case that fractionation methods that can measurecontinuous quality distributions should be developed, and that the temporaldevelopment of these distributions should be incorporated into SOM models.The measured continuous SOM quality distributions should hold valuableinformation not only for model development, but also for directinterpretation. Measuring continuous distributions requires that themeasurements along the quality variable are so frequent that thedistribution approaches the underlying continuum. Continuous distributionslead to possible simplifications of the model formulations, whichconsiderably reduce the number of parameters needed to describe SOMturnover. A general framework for SOM models representing SOM acrossmeasurable quality distributions is presented and simplifications forspecific situations are discussed. Finally, methods that have been used orhave the potential to be used to measure continuous quality SOMdistributions are reviewed. Generally, existing fractionation methods willhave to be modified to allow measurement of distributions or newfractionation techniques will have to be developed. Developing thedistributional models in concert with the fractionation methods to measurethe distributions will be a major task. We hope the current paper will helpgenerate the interest needed to accommodate this.

[学科分类] 地球化学与岩石