1. Single/simple/straight fertilizer: Fertilizers that supply only one nutrient. On the basis of the nutrient, they may be of the following types:

i. Fertilizer containing nitrogen in ammonium (NH4) form such as ammonium sulphate, ammonium chloride etc.

ii. Fertilizer containing nitrogen in nitrate (NO3) form such as calcium nitrate, sodium nitrate, potassium nitrate etc.

iii. Fertilizer containing nitrogen in amide form such as urea.

i. Fertilizers containing water soluble phosphorus such as super-phosphate, concentrated superphosphate, etc.

ii. Fertilizers containing citrate soluble phosphate such as dicalcium phosphate, basic slag etc.

iii. Fertilizers containing insoluble phosphate such as rock phosphate.

Such as potassium chloride, potassium sulphate etc.

2. Compound fertilizer:Fertilizers containing more than one nutrient through chemical bonding. Such as monoammonium phosphate (MAP), (diammonium phosphate (DAP) etc.

3. Mixed Fertilizer:Fertilizers prepared through mixing of different fertilizers. They may be of the following two types:

a. Complete fertilizer: Mixed fertilizer that contains 3 primary nutrients i.e. N, P and K.

b. Incomplete fertilizer: Mixed fertilizer that contains any 2 primary nutrients i.e. N and P or, K and P or, N and K. The quantity of nutrients varies in different fertilizer mixtures, based on which they may be classified as:

i. Low grade fertilizer mixtures: This category of mixture contains a total of plant nutrients up to or less than 14 per cent in it. Such mixtures are termed as low grade mixtures.

ii. Medium grade mixtures: This category of mixture contains a total of plant nutrients between 15 to 24 per cent in it.

iii. High grade mixtures: When the total nutrient contents range between 25 to 35 per cent in any mixture then the mixture is said to be of high grade.

Fertilizer mixtures can be prepared at the farm or at home. The following combinations should be avoided in preparing the mixed fertilizers at home:

• Ammonium sulphate, ammonium chloride, other ammoniacal fertilizers and nitrogenous organic manures with lime.

• Sodium nitrate or potassium nitrate with superphosphate.

• Nitrochalk with superphosphate or lime.

• Ammonium Sulphate-nitrate with lime.

• Urea with superphosphate.

• Superphosphate with lime or calcium carbonate or wood ashes.