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.
Plainfield is a town in Windham County, Connecticut, United States. The population was 15,405 at the 2010 census. The town comprises four villages: Plainfield (south, ZIP code 06374), Moosup (northeast, 06354), Wauregan (northwest, 06387), and Central Village (west, 06332). Each village has their own respective United States Post Office and fire department. The entire town is serviced by the 860 area code.