Simplified models of anoxia and denitrification in aggregated and simple-structured soils
Simplified models of anoxia and denitrification in aggregated and simple-structured soils
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DOI：
10.1111/j.1365-2389.1995.tb01347.x
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发表时间：
1995-12-01
影响因子：
4.2
通讯作者：
Vinten, AJA
中科院分区：
文献类型：
--
作者：
Arah, JRM;Vinten, AJA
两种互补的方法来模拟土壤缺氧和反硝化作用进行了比较。第一个假设的结构和生物异质性土壤基质（物理团聚体）和Michaelis-Menten动力学;第二个随机分布的圆柱形空气填充孔，均匀的代谢活动和零级反应动力学。简单的功能近似这两种模式的开发，让他们的差异进行探讨。当含水量达到团聚体饱和时，团聚体模型预测的缺氧分数和反硝化速率均超过简单结构模型的预测值。在干燥的土壤中，后者模型的预测通常超过前者的一个和三个数量级之间，差异减少的氧反应电位和平均半径的聚集体的增加。聚集体模型是更敏感的空气填充的孔隙度，并显示出降低反硝化效率时，硝酸盐浓度低。这是可能的预测更尖锐的污泥诱导的反硝化作用的事件，和一个较小的背景活动，比分布孔处理。无论采用这些或其他基于过程的反硝化处理方法，像这里介绍的简单近似方法都大大有助于纳入更大体积的系统模型。
Two complementary approaches to modelling soil anoxia and denitrification are compared. The first postulates a structurally and biologically heterogeneous soil matrix (physical aggregates) and Michaelis-Menten kinetics; the second a random distribution of cylindrical air-filled pores, a uniform metabolic activity and zero-order reaction kinetics. Simple functional approximations to both models are developed, allowing their differences to be explored. At water contents corresponding to aggregate saturation the anoxic fractions and denitrification rates predicted by the aggregate model exceed those predicted by the simple-structure model. In drier soils the predictions of the latter model typically exceed those of the former by between one and three orders of magnitude, the discrepancy lessening as the oxygen reaction potential and the mean radius of the aggregates increase. The aggregate model is much more sensitive to air-filled porosity, and shows a decreased denitrification efficiency when nitrate concentrations are low. It is likely to predict sharper rainfall-induced denitrification events, and a smaller background activity, than the distributed-pore treatment. Whichever of these or other process-based treatments of denitrification is adopted, simple approximations like those presented here greatly facilitate inclusion in larger-volume systems models.