Fertilizers

They are water soluble substance rich in nutrients which are added to soil to enhance the fertility of the soil.

Types of fertilizers

1. Organic fertilizers
2. Chemical fertilizers

Organic fertilizers: Those fertilizers which are obtained from theliving source are known as organic fertilizers. They are two types:

1. Green manure

   Green manure is defined as the practice of growing, ploughing under and mixing of green plants with soil to improve the fertility of the soil and ultimately crop productivity.

   

2. Compost Manure

   It is a kind of natural fertilizer which is prepared by mixing of cattle dung, poultry dropping and crop residues like remnants of straw, rotten vegetables, etc. The mixture is stored in a pit. Sometimes, lime is added to the pit containing mass to make a good kind of fertilizer. Gradually, by the action of micro-organisms, decomposition takes place and converts it into compost. It provides most of the nutrients required by plants and enhances the fertility of the soil.

Chemical fertilizers: The fertilizers prepared artificially in industry by using minerals are called chemical fertilizers.

1. Nitrogen fertilizers: The fertilizers which contain salts of nitrogen are called nitrogen fertilizers.

    

   Example: Ammonium sulphate Urea

    

   Functions of nitrogen

   1. It promotes fast growth and development of plants.
   2. It helps to form a large amount of protein and chlorophyll.
   3. It helps to increase the yield of crops.

   Effects of deficiency of nitrogen

   1. Low growth and development of plants
   2. Less synthesis of chlorophyll in leaves causing yellow leaves
   3. reduction in crop yielding
2. Phosphorous fertilizer: The fertilizers which contain salts of phosphorous are called phosphorous fertilizer.

    

   Example: Ammonium phosphate ; Calcium super phosphate

   

   Functions of phosphorous

   1. It helps in proper growth and development of plants.
   2. It makes the plant highly resistant to diseases.
   3. It helps in maturity of crops and seed formation.

   Effects of deficiency of phosphorous

   1. Less growth and development of roots.
   2. Reduction in disease resistance power of plant.
   3. Slow rate of cell division
3. Potassium fertilizers: Those fertilizers which contain salts of potassium are known as potassium fertilizers.

    

   Example: Potassium chloride Potassium nitrate

   

   Functions of potassium

   1. It helps in proper growth of flowers.
   2. It helps for healthy growth and development of roots and stalks of leaves.
   3. It helps to resist diseases.

   Effects of deficiency of potassium

   1. Decrease in the immunity power of plants against diseases.
   2. Withering of leaves
   3. The reduction of disease resistant power of plants.

   On the basis of number of primary nutrients supplied, fertilizers are of following three types:

   1. Single fertilizers: Those fertilizers which contain only one primary plant nutrient ie. Nitrogen or Phosphorous or Potassium are called single fertilizers.

       

      Example: Potassium chloride

   2. Mixed fertilizers: The fertilizers which contain more than one primary nutrient are called mixed fertilizers. Example:Potassium nitrate.

       

   3. Complete fertilizer or NPK fertilizer: Fertilizers which contain all the three nutrients ie Nitrogen, Phosphorous and Potassium as primary plant nutrients are known as complete fertilizers.

       

   Chemical pollution:

   Environmental deterioration due to unscientific and improper use of chemical substance is called chemical pollution.

   

   Causes:

   1. Insecticides and chemical fertilizers
   2. Refuses, waste materials and plastics
   3. Smoke from the means of transport and industries.
   4. Colors used in foodstuffs
   5. Synthetic clingers

       

   Control measures:

   1. Farmers should be suggested about the use of organic fertilizers rather than chemical fertilizers.
   2. Dirt must be properly disposed.
   3. Adequate dumping sites should be managed.
   4. Sustainable development should be carried out.
   5. We must emphasize reusing and recycling of wastes.
   6. Harmful smoke from industries should not be allowed to spread in air.
   7. Training should be given to the farmers regarding the use of chemical fertilizers,insecticides and pesticides.