The Nitrogen Cycle. Ammonium (NH4+) and nitrate (NO3â) are the predominate inorganic forms of nitrogen in soils. Ammonium exists in exchangeable and nonexchangeable forms. Nitrite (NO2) and nitrous oxide (N2O) are present in soil in lesser quantities. Plants normally use nitrogen in only the ammonium and nitrate forms. Nitrite is actually toxic to plants. The nitrogen cycle (Figure 5.2) shows reactions that various inorganic nitrogen compounds undergo in soil.
Ridgefield, Washington. Ridgefield is a city in the pastoral, rolling-hills countryside of northern Clark County, Washington, in the United States. The population was 4,763 at the 2010 census.
The village eliminated its July 4th fireworks in 2009, citing the $50,000 cost in the face of the difficult economy, but committed to retain its parade. Ridgefield Park is located at 40Â°51â²26â³N 74Â°01â²27â³W / 40.857119Â°N 74.024272Â°W / 40.857119; -74.024272 (40.857119, -74.024272).