A SIMPLE TOOL FOR PREDICTING THE DENITRIFICATION RATE POTENTIAL IN THE VADOSE ZONE BASED ON SAND, SILT OR CLAY COMPOSITION

Widespread pollution of ground and surface waters from nitrate (NO₃^-) contamination is of global concern to both public health and the environment. Quantifying the attenuation potential of NO₃^- on a watershed-scale is consequently of utmost importance. Denitrification rates have been found to vary significantly both spatially and temporally depending on different soil properties; however, progress in quantifying the magnitude of denitrification in different soils has been limited. The goal of this study was to develop a simplified approach for predicting the denitrification rate potential in the sub-surface based on easily measurable soil characteristics and/or soil properties reported on soil surveys. The goal was reached by compiling and summarizing data from previous studies, and by conducting statistical analyses to establish relationships between denitrification rates and soil properties. The results confirmed that variations in denitrification rates are strongly related to soil textural classes and water-filled porosity. A denitrification-rate prediction tool was developed based on these variables; thus allowing for more realistic denitrification-rate predictions on a watershed scale.