Dynamics of Carbon and Nitrogen in the Organic Matter of the Soil: A Generic Theory
Dynamics of Carbon and Nitrogen in the Organic Matter of the Soil: A Generic Theory
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土壤有机质中碳和氮的动态：通用理论
DOI：
10.1086/285213
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发表时间：
1991
期刊：
影响因子：
--
通讯作者：
G. Ågren
中科院分区：
文献类型：
--
作者：
E. Bosatta;G. Ågren
我们展示了如何从质量守恒出发，建立一个理论，通过一系列模型进行正确解释，涵盖大量当前使用的土壤有机质周转公式。以前使用的土壤有机质周转模型可以通过以适当的方式定义质量（q，q'）的分散函数（D）来导出。例如，将土壤有机质划分为一系列离散状态变量的传统方法是通过由 D(q,q') = Σdijδ(q - qi)δ(q' - qj) 定义的 D(q,q') 获得，其中求和扩展到土壤有机质成分。 qi 定义了相应的质量，dij 是从框 j 转移到框 i 的碳分数。在这方面，该理论充当这些其他表述的元理论。我们的基本原则是，土壤有机质在分解过程中经历的变化应被视为含碳化合物变化的连续体，被描述为土壤有机质质量的连续变化，因为它被以其为食的微生物群落所感知。驱动系统的力被封装在三个函数中：微生物产量与同化比 (e)、微生物生长速率 (u) 和 D。这些是基质质量的连续函数。我们演示了如何在不同的复杂程度下使用该理论，从通过可按不同阶截断的矩展开来处理有关驱动函数的完整信息，到绝热近似（其中色散函数仅用两个参数来近似）。连续系统的一个主要优点是更容易分析定性方面。该分析表明，分散的定性效果是延迟分解并增加氮固定，尽管 N:C 比率将接近较低值。由于分散而导致的分解延迟甚至可能如此之大，以致于一窝垃圾不能完全矿化。即使需要对土壤有机质进行离散描述，这里提出的理论也是有帮助的，因为它提供了一种检查速率和转移系数一致性的方法
We show how it is possible, starting with the conservation of mass, to formulate a theory that, properly interpreted through a series of models, encompasses a large number of currently used formulations of soil organic matter turnover. Previously used models of turnover of soil organic matter can be derived by defining dispersion functions (D) of qualities (q,q') in the appropriate way. For example, the conventional way of dividing soil organic matter into a series of discrete state variables is obtained with D(q,q') defined by D(q,q') = ∑dijδ(q - qi)δ(q' - qj), where the summation is extended over the soil organic matter components. The qi's define the corresponding qualities, and dij is the fraction of carbon transferred from box j to box i. The theory functions in this respect as a metatheory for these other formulations. Our basic tenet is that the changes soil organic matter undergoes during decomposition should be viewed as a continuum of changes in carbon-containing compounds, described as a continuous change in the quality of soil organic matter as it is perceived by the microbial community that is feeding on it. The forces driving the system are encapsulated in three functions: a microbial production-to-assimilation ratio (e), a microbial growth rate (u), and D. These are continuous functions of the substrate quality. We demonstrate how the theory can be used at different levels of complexity, from working with the full information about the driving functions through a moment expansion that can be truncated at different orders to an adiabatic approximation, where the dispersion function is approximated with only two parameters. A major advantage of a continuous system is that qualitative aspects are more easily analyzed. This analysis shows that the qualitative effects of dispersion are to retard decomposition and increase nitrogen immobilization, although the N:C ratio will approach lower values. The retardation of the decomposition due to dispersion can even be so large that a litter cohort cannot be completelymineralized. Even where a discrete description of the soil organic matter is desirable, the theory formulated here is helpful, because it provides a way of checking the consistency of rate and transfer coefficients