Fertilizers and pesticides tnpsc notes

Manures and Fertilizers

Manures are decomposed and organic matter that is derived from animals and plants. As it supplies nutrients to the crops and plants, it is also beneficial in different ways.

Manures also enhance the biological activities in the soil, aeration and also improve the water holding capacity of the soil. As these Manures decompose slowly and release the nutrients slowly they can be used as organic fertilizers in agriculture.

Classification of Organic Manures

It is classified into three groups. One is of plant origin, and another is of animal origin. The third one is composite derived from both plants and animals.

1.Manures of Plant Origin

Oil Cake such as Edible oil cakes. Example: Groundnut cake, linseed cake, rapeseed cake, sesamum cake, etc. Non Edible cake includes Karanj cake, neem cake, castor cake, etc.

Also plant residues such as Straw, husks, stalks, sawdust, and would ask.

Green Manures: These are crops that are raised and converted into manures. Examples: Dhaincha and Sunn Hemp etc

2. Manures of Animal Origin

These manures are made from Animals, Poultry, or Fish leftovers. It includes animal’s settled sludge, (dry) dried blood, night soil and sludge manure, fish manure bonemeal, cattle dung and urine mixed, sheep dung and urine mixed, pig manure, poultry manure, etc.

3. Composite Manures

These are manures of both plant and animal origin. These are made using sugarcane trash, paddy straw, plant debris, weeds, etc.

4. Vermicompost

It is developed using earthworms. When earthworms consume organic matter and excrete it as cast and these casts are rich in plant nutrients. This is called Vermicompost.


These are alternatives to Manures that are manufactured commercially from inorganic chemicals. It is ready to use and contains a high amount of nutrients than manures.

Chemical fertilizers are a source of single nutrients and therefore it is also called Sole Fertilizers.

Such fertilizers which provide more than one nutrient are called Mix or Complex fertilizers.

Advantages of Fertilizers

It is easily available and only a less or calculated amount of fertilizer can be used to get maximum benefit and it is cheaper.

It is available in different formulations and can be easily transported to different parts.

It is highly efficient and contains a lot of nutrition, that can be used even in arid regions such as deserts, etc, and can get maximum output.

Types of Fertilizers

Sole Fertilizers – It contains only a single nutrient. Ex:

Nitrogenous Fertilizers – Nitrogenous Fertilizers such as Urea, Ammonium sulphate, calcium ammonium nitrate, etc.

Phosphorus or Phosphatic fertilizers – Single superphosphate, triple superphosphate, dicalcium phosphate.

Potassic Fertilisers – Potash, and Potassium sulphate.

Mixed Fertilizers – It is also called complex fertilizers as these fertilizers are with a source of more than one macronutrient for the plant.

Example: di-ammonium phosphate (18:46:0), nitro-phosphate (20:20:0), ammonium phosphate (28:0:0), ammonium phosphate sulphate (16:20:0), calcium ammonium nitrate (8% Ca and 21–27% N), etc.



* * All the Notes in this blog, are referred from Tamil Nadu State Board Books and Samacheer Kalvi Books. Kindly check with the original Tamil Nadu state board books and Ncert Books.