Drainage ditches are a key conduit of nitrogen (N) from agricultural fields to surface water. The effect of ditch dredging, a common practice to improve drainage, on the fate of N in ditch effluent is not well understood. This study evaluated the effect of dredging on N transport in drainage ditches of the Delmarva Peninsula. Sediments from two ditches draining a single field were collected (0-...

The extraction behavior of new bi-functional ligands containing sulfoxide and amide groups viz. N,N'-dibutyl carbamoyl methyl phenyl sulfoxide (L1) and N,N'-dibutyl carbamoyl methyl benzyl sulfoxide (L2) towards the U(VI), Pu(IV) and Am(III) ions from nitric acid was studied. Both of these extractants showed appreciable extractions for U(VI) and Pu(IV) from 1 to 9.5 M nitric acid concentrations...

it more susceptible to leaching (Albus and Knighton, 1998). Higher moisture contents will also raise microbial Groundwater and surface water are significant resources for rural activity including mineralization (Skopp et al., 1990). water supplies, and certain agricultural practices may have substantial effects on these resources. An 11-yr study was started in 1989 near The increase in minerali...

Shewanella loihica strain PV-4 harbors both a functional denitrification (NO3 (-)→N2) and a respiratory ammonification (NO3 (-)→NH4 (+)) pathway. Batch and chemostat experiments revealed that NO2 (-) affects pathway selection and the formation of reduced products. Strain PV-4 cells grown with NO2 (-) as the sole electron acceptor produced exclusively NH4 (+). With NO3 (-) as the electron accept...

Temperate forests receive some of the highest rates of nitrogen (N) deposition in the world. While numerous studies have investigated the effects of N enrichment on forests, there is little consensus on why some forests become N saturated while others do not. To investigate this, we used a multi-factor metaanalysis to simultaneously estimate the relative importance of several environmental, exp...

OsNRT1.1a is a low-affinity nitrate (NO3 (-) ) transporter gene. In this study, another mRNA splicing product, OsNRT1.1b, putatively encoding a protein with six transmembrane domains, was identified based on the rice genomic database and bioinformatics analysis. OsNRT1.1a/OsNRT1.1b expression in Xenopus oocytes showed OsNRT1.1a-expressing oocytes accumulated (15) N levels to about half as compa...

As a vital beverage crop, tea has been extensively planted in tropical and subtropical regions. Nitrogen (N) levels and forms are closely related to tea quality. Based on different N levels and forms, we studied changes in NO3- and NH4+ fluxes in tea roots utilizing scanning ion-selective electrode technique. Our results showed that under both single and mixed N forms, influx rates of NO3- were...

Constructed wetlands positioned in the landscape between row crop agriculture and surface waters can be used to intercept tile drainage and serve as agricultural waste water detention basins. A potential exit pathway in constructed wetlands for detained water and possibly NO3 -N is via seepage through and under an earthen berm. The objective of this study was to determine if seepage was an impo...

Leaching of NO3-N from agricultural lands often occurs in well-defined hot spot areas when viewed across geographical regions of hundreds or thousands of km 2 and often appears as areas of high NO3-N concentrations in shallow underlying aquifers. Delineation of high-NO3-N zones can be achieved by combining models such the Nitrate Leaching and Economic Analysis Package (NLEAP) with Geographical ...