How does water price affect irrigation technology adoption?

fairly consistent with depth from the surface to the water table. There is no evidence from our data that denitrification is a significant process at any of the sites, with the possible exception of the Salinas Valley septic tank site. Thus, except for one site in the eight main test sites, the results demonstrate that measuring the 615N value immediately below the NO3 source can be an accurate indicator of the fingerprint of that source and that, under the conditions prevailing at these sites, the fingerprint will not change much during NO3 transport to groundwater. This is a very important conclusion for use of the N isotope technique to indicate sources of NO3 in groundwater. Nevertheless, users of the &5N approach should be aware of the potential for mixing of 615N from multiple sources and of denitrification under some circumstances. Careful hydrogeologic characterization as well as sampling of both the unsaturated and saturated zones beneath potential sources are therefore typically required for successful application of the 615N approach.