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.
April 5, 1988. The Ridge is a historic home located at Derwood, Montgomery County, Maryland, United States. It is a 11â2-story Flemish bond brick house on a fieldstone foundation. The decorative detailing in the main house reflects Georgian, Federal, and Greek Revival influences.