Attributing nitrogen export to specific land use within heterogeneous catchments remains a challenge due the spatio-temporal variability in conditions influencing mobilization and fate of species. This study demonstrates that measurement dual stable isotopes nitrate, taken along with routine tributary nitrate (NO3−-N) ammonium (NH4+-N), aids apportioning sources overall load during wet periods....

urea is the most common form of nitrogen fertilizer used in sugar beet cultivation. urea has a high solubility and its losses are high and consequently its efficiency is low. it is supposed that urea solubility can be limited and its efficiency can be increased by using slow-release nitrogen fertilizers. by conducting an experiment in three important sugar beet cultivation areas of khorasan pro...

We conducted a series of stepwise NO3 2 additions to investigate the response of NO3 2 uptake to short-term (acute) changes in N concentration in 3 prairie streams. Observed NO3 2 uptake rates increased with short-term elevations in NO3 2 concentration and were consistent with linear and Michaelis–Menten kinetics models. We compiled these data with uptake rates from additional published studies...

This study was completed to understand the resilience of an ion exchange (IEX) process for its ability remove variable ammonium (NH4+-N) loads) and prove environmental benefits through a life cycle assessment (LCA). The tertiary 10 m3/day demonstration scale IEX fed with NH4+-N concentrations (<0.006–26 mg /L) naturally found in municipal wastewater. Zeolite-N used as media regeneration 10% pot...

The transport of organic N compounds to the shoot in the xylem sap of nodulated soybean plants was investigated in an attempt to better understand the changes in N metabolism under root hypoxia (first 5 days of flooding), with different sources of N in the medium. NO3 is beneficial for tolerance of plants to waterlogging, whereas other N sources such as NH4 + and NH4NO3, are not. Nevertheless, ...

The purpose of this field study was to determine the relationship between environmental conditions, particularly high nitrate (NO3 ), low salinity events, and both nitrogen (N) storage (NO3 , ammonium [NH4 ], free amino acids [FAA], protein, and total N) and nitrate reductase (NR) activity in the macroalgae Enteromorpha lingulata and Gelidium pusillum in the lower Mobile Bay estuary (Alabama, U...

Myriophyllum elatinoides was reported to effectively treat wastewater by removing nitrogen (N) and phosphorus (P). However, little is known about the abundance and community structure of ammonia-oxidizing microorganisms associated with M. elatinoides purification systems. The objective of this research was to characterize the abundance and community structure of ammonia-oxidizing microorganisms...

Urban regions of southern California receive up to 45 kg Nha y from nitrogen (N) deposition. A field decomposition study was done using N-labelled litter of the widespread exotic annual grass Bromus diandrus to determine whether elevated soil N is strictly from N deposition or whether N mineralization rates from litter are also increased under N deposition. Tissue N and lignin concentrations, w...