Nitrogenous Fertilizers:

According to the manner in which their nitrogen is combined with other elements, the nitrogenous fertilisers are divided into four groups; nitrate, ammonia, and ammonium salts, chemical compounds containing nitrogen in the amide form, and plant and animal by-products.

I. Inorganic Nitrogenous Fertilizers

Inorganic substances containing large amount of nitrogen come under this category. It is further divided into following groups according to the form of nitrogen they contain.

1. Nitrate fertilizers (NO₃^- ): Nitrogen present in these fertilizers are in nitrate form, NO₃ ^- which are rapidly dissociated to release NO3^-ions and readily absorbed by the plants. Nitrate ions highly reactive and mobile are susceptible to losses due to leaching and under water-logged conditions by denitrification. They are alkaline in their residual effect in soil. Following are the nitrate fertilisers:

S. No.	Fertiliser	% N
1	Sodium nitrate (NaNO3)	16%N
2	Calcium nitrate Ca(NO3) 2	15.5%N

1. Ammonium fertilizers (NH₄⁺): Ammonium fertilizers are soluble in water and, as such, absorbed on the soil colloids and thus protected from being washed away by run off or by leaching. Some crops like rice, sugarcane, tuber crop, seedlings directly utilise ammonium form of these fertilizers. The absorbed ammonium ions on soil collections are transformed to nitrate slowly and taken up by most of the crops. They are acidic in their residual effect in soil. Following are the ammonium fertilisers:
   

S. No.	Fertiliser	% N
1	Ammonium Sulphate –(NH4)2SO4	20.6%N
2	Ammonium Chloride –NH4CL	25%N
3	Ammonium phosphate---NH4 (H2PO4)	20%N
4	Anhydrous ammonia --NH3	82%N
5	Ammonia Solution --NH3 in water	20 to 25%N

2. Nitrate and Ammonium fertilizers (Nitrate, NO3^- and ammonium, NH₄⁺ ): These fertilizers contain nitrogen in both nitrate (NO3^- ) and ammonium forms (NH₄⁺ ). The nitrate nitrogen is readily available to plants for immediate need, whereas ammonium nitrogen becomes available to plants at a later stage, when it is transformed by microbiological process to nitrate. They are soluble in water and suitable for most of the crops and soils. They are acidic in its residual effect.
   

S. No.	Fertiliser	% N
1	Ammonium nitrate---NH4NO3	33 to 34%N
2	Calcium Ammonium Nitrate (CAN) Ca(No3) 2NH4NO3	25%N
3	Ammonium Sulphate Nitrate (ASN) (NH4) 2SO4NH4NO3	26%N


II. Organic Nitrogenous Fertilizers:

These fertilisers contain nitrogen in organic form. These include plant and animal by-products.

These fertilisers are relatively slow-acting but they supply nitrogen for a longer period.

3. Amide Fertilizers (Amine, NH2 or amide, CN2): These fertilizers contains nitrogen in organic compounds as amide—NH₂ or ---- CN _{2 ,} not directly available to plants, as such , but quickly converted by soil microbes to ammoniacal and nitrate form and then utilised. Amide fertilisers are:
   

S. No.	Fertiliser	% N
1	Urea CO(NH2) 2	46%N
2	Calcium cyanamide CaCN2	21%N

4. Slow release nitrogenous fertilizers: These are newly developed fertilisers which release nitrogen in soil very slowly so that it may be available to the plants for longer period of time. Use of these materials result in better utilization of applied nitrogen by the growing crop plants and reduce losses.