It is taken into the soil by bacteria, some algae, lightning, and other means. Nitrate is the form of nitrogen most used by plants for growth and development. Nitrate is the form that can most easily be lost to groundwater. Ammonium Nitrogen NH 4 Ammonium taken in by plants is used directly in proteins. This form is not lost as easily from the soil.
Organic nitrogen exists in many different forms.
It is changed into ammonium, then into nitrates, by microorganisms. Both of these inorganic forms can be used by the plant. This is because nitrate is very mobile and easily moves with water. The concern of nitrates and water quality is generally directed at groundwater. However, nitrates can also enter surface waters such as ponds, streams and rivers.