Sarah Izhar Content Writer
Content Writer
The natural or chemical substances used to improve the fertility and productivity of crops are called fertilizers.
- These substances enrich the soil with an adequate amount of nutrients for plant growth and development.
- Fertilizers can be produced naturally or artificially and are of two types: biofertilizers and chemical fertilizers.
Fertilizers
What is a Biofertilizer?
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A biofertilizer or microbial fertilizer is a type of fertilizer that contains living cells of microorganisms.
- We add biofertilizers to the soil in order to improve its nutritional status.
- These are a much better choice than chemical fertilizers because they are safe and they don’t harm the environment.
- Biofertilizers help to control diseases while chemical-based ones do not.
- Some commonly used bio-fertilizers include rhizobium, Azotobacter, and blue algae.
What is a Chemical fertilizer?
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A chemical fertilizer is a type of fertilizer that is made using chemical substances. These are also called synthetic fertilizers.
- Chemical fertilizers contain essential nutrients that improve the growth of the plant.
- The use of these fertilizers results in faster growth and yield of the crops.
- Chemical fertilizers rich in nitrogen, phosphorus, and potassium are commonly used for plant growth.
Differences Between Biofertilizers and Chemical Fertilizers
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The difference between biofertilizers and chemical fertilizers depends on many parameters like type, composition, technique used, shelf life, etc. The table highlights the differences between the two:
| Parameters | Biofertilizers | Chemical Fertilizers |
|---|---|---|
| Type | These are the substances that contain microorganisms. | These are the substances synthesized in industries by the use of natural elements. |
| Composition | Composed of nitrogen-fixing microorganisms, algae, and solubilizers. | Composed of nitrogen, potassium, and phosphorus. |
| Cost | Cheaper than chemical fertilizers | Expensive than biofertilizers |
| Duration | More time is required for the fertilizers to reach the plant. | Less time is required for the fertilizers to reach the plant. |
| Longevity | Shorter life span. | Longer life-span. |
| Nutrient Density | Low. | High. |
| Salt Concentration | The salt concentration is zero. | The salt concentration is high. |
| Source of energy | Renewable source of energy. | Non-renewable source of energy. |
| NPK Concentration | Low. | High. |
| Method of Preparation | Prepared manually. | Prepared using equipment. |
| Impact | It has a positive impact on the environment as they are eco-friendly. | It harms the environment as they are toxic in nature. |
| Sources | Fungi, cyanobacteria, bacteria. | Ammonium nitrate, phosphate, ammonium phosphate. |
Things to Remember
- The difference between biofertilizers and chemical fertilizers depends on the type and composition of fertilizer.
- Rhizobium, a symbiotic nitrogen-fixing bacteria, acts like a biofertilizer.
- Vermicomposting is a sustainable method to enhance the fertility of soil.
- Azospirillum helps in promoting plant growth and enhances root development.
- Nitrogen, phosphorus, and potassium are the three essential components required for the growth of the plant.
Sample Questions
Ques. Write any two disadvantages of chemical fertilizers. (2 marks)
Ans. The two disadvantages of chemical fertilizers are:
- Excessive use can degrade the soil by increasing soil acidity.
- The use of chemical salts (ammonia, potassium, etc) can cause salt burns.
Ques. Differentiate between organic and biofertilizers? (2 marks)
Ans. The following table shows the difference between biofertilizers and organic fertilizers.
| Biofertilizers | Organic fertilizers |
|---|---|
| They contain living organisms like algae, bacteria, fungi | They are obtained from organic sources like compost, vermicompost, manure, etc. |
| Improves soil structure, and water-holding capacity | Improves nutrient content and microbial activity |
Ques. What are the advantages of biofertilizers? (2 marks)
Ans. The advantages of biofertilizers are:
- These fertilizers do not change the natural composition of the soil.
- Biofertilizers prevent the attack of disease-causing pathogens.
- They are cheap and eco-friendly.
Ques. How are chemical fertilizers made? (2 marks)
Ans. Major and minor nutrients combine to produce chemical fertilizers industrially.
- Nitrogen, phosphorus, and potassium are the major nutrients used in the synthesis of chemical fertilizers.
- The excess use of these fertilizers can cause soil, air, and water pollution.
Ques. Give a few examples of Phosphate-fixing bacteria. (1 mark)
Ans. Azotobacter, Rhizobium, Azospirillum, and Acetobacter are examples of phosphate-fixing bacteria.
Ques. What happens if we don’t use fertilizers? (2 marks)
Ans. Plants require nutrients for their growth and development.
- If fertilizers are not used they won’t get sufficient nutrients required for nourishment.
- Plants may get infected by pests causing diseases and even plant death.
Ques. What is a seed treatment? (2 marks)
Ans. A seed treatment is one of the methods of application of biofertilizers.
- In this method, about 200 grams of biofertilizer is mixed with 350 ml of water.
- To this, 10 grams of seed along with adhesive like gum arabica is added.
- This mixture is spread over a clean cloth, allowed to dry, and used immediately.
Ques. Are there any benefits of artificial fertilizers? (2 marks)
Ans. Yes, artificial fertilizers have the following benefits:
- Nitrogen in addition to phosphorus and potassium is essential for healthy plants.
- Chemical fertilizers hasten the increase in crop yield.
Ques. Explain any two types of biofertilizers. (3 marks)
Ans. The two types of biofertilizers are free-living nitrogen-fixing bacteria and symbiotic nitrogen-fixing bacteria.
- Free-living nitrogen-fixing- These types of bacteria are found in soil and are responsible for nitrogen fixation and enhancing crop yield. Azotobacter is one such example.
- Symbiotic nitrogen-fixing- These types of bacteria are present in the root nodules of plants (legumes). It is responsible for improving soil quality. Example- Rhizobium.
Ques. Vermicompost is a biofertilizer. How? (3 marks)
Ans. Yes, vermicompost is an example of a biofertilizer.
- Vermicomposting produces plants that are good in quantity and quality.
- The compost contains enzymes such as lipase, amylase, cellulose, and chitinase.
- These enzymes help in the breakdown of organic matter so that it can be taken by the roots of plants.
Ques. What is the best fertilizer for growing potatoes? (2 marks)
Ans. Potatoes need plenty of fertilizers to achieve a good yield.
- The kind of fertilizer which is best for growing potatoes depends on the condition of the soil.
- Manure is an example of a natural fertilizer, and it can also be used because it is rich in nutrients that are so important to potatoes as they grow.
- Ammonium sulfate can also be used as far as synthetic fertilizers are concerned.
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