Nitrification

• Plants use light energy to produce organic compounds. Some bacteria, however, obtain their energy from chemical reactions involving inorganic ions.
• The conversion of ammonium ions to nitrate ions is known as nitrification. It is an oxidation reaction, and so releases energy. It is carried out by free-living soil microorganisms called nitrifying bacteria.
• The process of nitrification occurs across two major stages : 1 - oxidation of ammonium ions to nitrite ions (NO2^-). 2 - oxidation of nitrite ions to nitrate ions (NO3^-).
• Nitrifiying bacteria require oxygen to carry out these conversions and so they require a soil that has many air spaces.
• To raise productivity, it is important for farmers to keep soil structure light and well aerated by ploughing. Good drainage also prevents the air spaces from being filled with water and so prevents air from being forced out of the soil.