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.
Sponsored Topics. Ridgely is a town in Lake County, Tennessee, United States. The population was 1,667 at the 2000 census. Ridgely is located at 36Â°15â²52â³N 89Â°28â²58â³W / 36.26444Â°N 89.48278Â°W / 36.26444; -89.48278 (36.264559, -89.482668). According to the United States Census Bureau, the town has a total area of 0.7 square miles (1.8 kmÂ²), all of it land.