The measurement and analysis of denitrification rates obtained using soil columns from river marginal wetlands
1999; Wiley; Volume: 15; Issue: 3 Linguagem: Inglês
10.1111/j.1475-2743.1999.tb00081.x
ISSN1475-2743
AutoresN. Flynn, Peter J. Gardner, Edward Maltby,
Tópico(s)Wastewater Treatment and Nitrogen Removal
ResumoAbstract. Soil cores from river marginal wetlands from three sites in the UK (Torridge and Severn catchments), sampled and restrained in PVC piping, were flooded with dilute aqueous potassium nitrate. Half of the cores were sterilized prior to flooding to destroy the denitrifying bacteria. The change in nitrate concentration in the flood‐water was measured over time. It is argued that the observed nitrate depletion rates (from 1.2 to 4.7 kg ha −1 d −1 ) is the result of microbially‐mediated denitrification. The results show the method to be a simple and direct procedure for the assessment of spatial variation in nitrate‐sink capacity. The depth of the denitrifying layer at the soil–water interface was confirmed to be of the order of a few mm only. A one‐dimensional model for the diffusive flux in the flooded soil was developed which, on differentiation, gave a predictive expression for denitrification rate in terms of the effective soil diffusion coefficient for nitrate, the flood‐water depth and concentration, and the thickness of the microbially active zone.
Referência(s)