nitrous oxide (n2o) has significant impact on global warming and leads to the depletion of ozone in the stratosphere. agricultural soil is regarded as a major source of n2o emissions. in recent years, greenhouse grown vegetables have rapidly developed in china. although excessive fertilizer application in greenhouse vegetable production can result in increased n2o emissions, research data on su...

The adoption rate of winter cover crops (WCCs) as an effective conservation management practice to help reduce agricultural nutrient loads in the Chesapeake Bay (CB) is increasing. However, the WCC potential for water quality improvement has not been fully realized at the watershed scale. This study was conducted to evaluate the long-term impact of WCCs on hydrology and NO3-N loads in two adjac...

We compared growth kinetics of Prorocentrum donghaiense cultures on different nitrogen (N) compounds including nitrate (NO3-), ammonium (NH4+), urea, glutamic acid (glu), dialanine (diala) and cyanate. P. donghaiense exhibited standard Monod-type growth kinetics over a range of N concentraions (0.5-500 μmol N L-1 for NO3- and NH4+, 0.5-50 μmol N L-1 for urea, 0.5-100 μmol N L-1 for glu and cyan...

Implementation of artificial subsurface drainage (tile drainage) for cultivation of row crops in poorly-drained areas of the Upper Midwest of the United States has enabled the region to be one of the most agriculturally productive areas of the world; but has also resulted in loss of wetland ecosystems, altered hydrology, and increased transport of nitrate-nitrogen (NO3-N) to surface water. The ...

The major ion chemistry of water from an 11.42-km reach of the Pajaro River, a losing stream in central coastal California, shows a consistent pattern of higher concentrations during the 2 (dry) half of the water year. Most solutes are conserved during flow along the reach, but [NO3 ] decreases by ;30% and is accompanied by net loss of channel discharge and extensive surface–subsurface exchange...

We monitored the water quality and hydrological conditions of a horizontal subsurface constructed wetland (HSSF-CW) in Beijing, China, for two years. We simulated the area-based constant and the temperature coefficient with the first-order kinetic model. We examined the relationships between the nitrogen (N) removal rate, N load, seasonal variations in the N removal rate, and environmental fact...

This study explored the feasibility of using granular ferric hydroxide as adsorbent for the removal of NO3-N. Optimum conditions for NO3-N removal were found to be pH 5.0 and equilibrium time 80min. The equilibrium sorption isotherm was better described by Langmuir sorption isotherm model. The maximum sorption capacity of granular ferric hydroxide was 4.254mg/g at 298K. A comparison of four kin...

Physical, chemical, hydrologic, and biologic factors affecting nitrate (NO3(-)) removal were evaluated in three agricultural streams draining orchard/dairy and row crop settings. Using 3-d "snapshots" during biotically active periods, we estimated reach-level NO3(-) sources, NO3(-) mass balance, in-stream processing (nitrification, denitrification, and NO3(-) uptake), and NO3(-) retention poten...