This research was conducted with Biscayne marl soil and Krome gravelly loam from Florida and Quincy fine sand and Warden silt loam from Washington to determine ammonia (NH3) volatilization at various temperature and soil water regimes. Potassium nitrate (KNO3), ammonium nitrate (NH4NO3), ammonium sulfate [(NH4)2SO4], or urea were applied to the soil at a rate of 75 kg N ha . Soil water regime w...

An axenically cultured isolate of single-celled freshwater microalgae (Chlorella sp.) metabolized toxic selenate to volatile dimethylselenide at exceptionally high rates when transferred from mineral-nutrient solution to water for 24 h. The Se-volatilization rates were orders of magnitude higher than those similarly measured for wetland macroalgae and higher plants. Ninety percent of 20 micro m...

Soil drought, that can be enhanced by global warming increases ammonia (NH3) volatilization. This laboratory study was conducted with two soils: Krome Gravelly Loam (KGL) from Florida and Warden Silt Loam (WSL) from Washington State and two fertilizers: Ammonium sulfate [(NH4)2SO4] or ammonium nitrate (NH4NO3). Two water regimes including 20 and 80% Field Capacity (FC) were used at 20°C which i...

Cattle slurry was surface-applied to bare soil in two experiments in the period September­ November 1987, while in April-May 1988 two experiments were carried out in which the slur­ ry was mixed with the upper 6 an of the soil with a cultivator immediately after spreading. The 1987 experiments both lasted 18 days, the 1988 experiments 9 days. A micrometcorologi· cal technique, which did not dis...

In situ mesocosm experiments were performed to examine dissolved gaseous mercury (DGM), mercury volatilization, and sediment interactions in a frozen freshwater fluvial lake (Lake St. Louis, Beauharnois, QC). Two large in situ mesocosm cylinders, one open-bottomed and one close-bottomed (no sediment diffusion), were used to isolate the water column and minimize advection. Mercury volatilization...

Conservation tillage practices are being implemented by many farmers to conserve water and soil resources. These practices may modify the soil surface in ways that differentially effect dissipation of pesticide when compared to conventionally tilled fields. We measured volatilization of atrazine [2-chloro-4-ethylamino-6-isopropylamino-s-triazine] and alachlor [2-chloro-2'-6'-diethyl-n-(methoxym...