Research has shown that aluminum sulfate (alum) and phosphoric acid greatly reduce ammonia (NH3) volatilization from poultry litter; however, no studies have yet reported the effects of these amendments on field-scale composting of poultry litter. The objectives of this study were to (i) evaluate NH3 volatilization from composting litter by measuring both NH3 volatilization and changes in total...

Transgenic tobacco plants engineered with bacterial merA and merB genes via the chloroplast genome were investigated to study the uptake, translocation of different forms of mercury (Hg) from roots to shoots, and their volatilization. Untransformed plants, regardless of the form of Hg supplied, reached a saturation point at 200 microM of phenylmercuric acetate (PMA) or HgCl2, accumulating Hg co...

Tillage practices and nitrogen (N) sources are important factors affecting rice production. Few studies, however, have examined the interactions between tillage practices and N fertilizer sources on NH3 volatilization, nitrogen use efficiency (NUE), and rice grain yield. This study aimed to investigate the effects of N fertilizer sources (no N fertilizer, inorganic N fertilizer, organic N ferti...

Urea is the most widely used nitrogen (N) fertilizer in direct-seeded, delayed-flood rice production. Urea fertilizer is susceptible to loss as ammonia gas to the atmosphere if not flooded in a timely manner. A urease inhibitor [i.e. N-(n-butyl) thiophosphorictriamide; NBPT] is recommended when a timely flood cannot be established. Recent research has indicated that when relative humidity (RH) ...

An 8-yr study was conducted to better understand factors influencing year-to-year variability in field-scale herbicide volatilization and surface runoff losses. The 21-ha research site is located at the USDA-ARS Beltsville Agricultural Research Center in Beltsville, MD. Site location, herbicide formulations, and agricultural management practices remained unchanged throughout the duration of the...

Selenium (Se) can be assimilated and volatilized via the sulfate assimilation pathway. Cystathionine-gamma-synthase (CGS) is thought to catalyze the synthesis of Se-cystathionine from Se-cysteine, the first step in the conversion of Se-cysteine to volatile dimethylselenide. Here the hypothesis was tested that CGS is a rate-limiting enzyme for Se volatilization. Cystathionine-gamma-synthase from...

Compared with dry and wet deposition fluxes, air-water exchange flux cannot be directly measured experimentally. Its model-based calculation contains considerable uncertainty because of the uncertainties in input parameters. To capture the inherent variability of air-water exchange flux of PCBs across the lower Great Lakes and to calculate their annual gross volatilization loss, 57 pairs of air...

Selenium (Se) can be assimilated and volatilized via the sulfate assimilation pathway. Cystathionine-c-synthase (CGS) is thought to catalyze the synthesis of Se-cystathionine from Se-cysteine, the first step in the conversion of Se-cysteine to volatile dimethylselenide. Here the hypothesis was tested that CGS is a rate-limiting enzyme for Se volatilization. Cystathionine-c-synthase from Arabido...

Constructed wetlands have been used effectively to reduce the mass loads of organic and nutrient components from swine anaerobic lagoons. Continuous marsh wetlands with gentle slope and intermittent flows seem to be the best for promoting oxidation and minimizing ammonia volatilization. However, the pond section of the marsh-pond-marsh section could potentially be effectively aerated by mechani...