Biofertilizers: Definition, Types, Components, Importance, Advantages
Biofertilizers are living microorganisms like bacteria, fungi, and algae that improve soil fertility by fixing nitrogen, solubilizing phosphorus, and promoting plant growth. They are eco-friendly, cost-effective, and play a vital role in sustainable agriculture. Examples include Rhizobium, Azospirillum, and blue-green algae, making this a key NEET Biology topic.
This Story also Contains
- What are Biofertilizers?
- Components of Biofertilizers
- Types of Biofertilizers
- Importance of Biofertilizers
- Pros and Cons of Biofertilizers
- Tips, Tricks, & Mnemonics
- Biofertilizers NEET MCQs
- FAQs on Biofertilizers
Biofertilizers are organic fertilizers containing beneficial microorganisms that enhance plant growth by increasing the availability of essential nutrients like nitrogen and phosphorus. These eco-friendly alternatives help in restoring soil fertility naturally without causing long-term harm. They do not harm soil health. They promote organic farming and therefore help in maintaining soil health, reducing the use of harmful chemicals and overall contributing to the healthy ecosystem.
What are Biofertilizers?
Biofertilizers are substances that contain living microorganisms. It promotes plant growth and development by increasing the supply of nutrients. It adds nutrients through a natural process of nitrogen fixation and solubilizing phosphorus. They help to build up the soil micro flora and thereby the soil health. Biofertilizers are recommended for improving the soil fertility in organic farming.
Components of Biofertilizers
The microorganisms in biofertilizers provide nutrients to plants, increase soil fertility, and promote soil health. The main components of biofertilizers are:
Components | Explanation |
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Fungi |
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Organic Matter |
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Vitamins and Growth Hormones |
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Types of Biofertilizers
The primary categories of biofertilizers are as follows:
Type of Biofertilizers | Explanation |
Symbiotic nitrogen-fixing bacteria |
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Loose Association of nitrogen-fixing bacteria |
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Importance of Biofertilizers
Some Basic importance of Biofertilizers are discussed below:
Biofertilizers enhance plant growth and soil quality.
They prevent the spread of diseases.
They are economical and environmentally favourable.
As natural fertilizers, biofertilizers shield the ecosystem from contaminants.
They remove a lot of dangerous elements from the soil that can wreak havoc on plants.
Even in semi-arid environments, biofertilizers are successful.
Pros and Cons of Biofertilizers
Biofertilizers have both pros and cons. Some of the important ones are discussed below:
Pros of Biofertilizers | Cons of Biofertilizers |
These are made using natural sources and they do not harm the involvement of plants, animals and humans in any way. | Bio fertilizers work slowly and textiles show the results. |
They can be easily produced at a low cost which reduces the need for expensive fertilizers and pesticides. | The bio-fertilizers also have shorter shelf life which requires specific storage conditions to maintain the effectiveness of the biofertilizer. |
It contains microorganisms that can fix atmospheric nitrogen, increase soil fertility and also give important nutrients to the soil. | It requires strict quality control in order to ensure a good result. Poor quality of biofertilizer can lead to bad results. |
One of the major cons of biofertilizers is they reduce the risk of harmful chemicals going into the soil and waterways. This reduces the various types of pollution of the environment. | Different types of biofertilizers have unique application needs which require proper use of biofertilizers in order to increase the performance. |
It increases plant growth and productivity which leads to improved crop yield and quality. |
Tips, Tricks, & Mnemonics
It takes effort to remember everything in a single go. We made the entire problem easy. Some of the tricks regarding Biofertilizers are given below which you can use to memorise the important points.
Components of Biofertilizers
"BFAEO: Bacteria, Fungi, Algae, Enzymes, Organic matter"
B: Bacteria (e.g., Rhizobium, Azospirillum) help fix nitrogen and improve soil fertility.
F: Fungi (e.g., mycorrhizal fungi, Trichoderma) enhance nutrient absorption and control diseases.
A: Algae (e.g., blue-green algae) can fix atmospheric nitrogen and improve soil health.
E: Enzymes assist in breaking down organic matter, making nutrients more available to plants.
O: Organic matter (e.g., compost) enriches the soil and supports microbial activity.
Types of Biofertilizers
"SLA: Symbiotic, Loose Association, Algae"
S: Symbiotic Nitrogen-Fixing Bacteria (e.g., Rhizobium) form relationships with plants to fix nitrogen.
L: Loose Association of Nitrogen-Fixing Bacteria (e.g., Azospirillum) live near roots, aiding in nutrient uptake.
A: Algal Biofertilizers utilize blue-green algae to enhance soil fertility and provide nutrients.
Advantages of Biofertilizers
"CIEE: Cost-effective, Improved fertility, Eco-friendly, Enhanced yield"
C: Cost-effective alternatives to chemical fertilizers.
I: Improves soil fertility by enhancing nutrient availability.
E: Eco-friendly as they are made from natural sources and reduce pollution.
E: Enhances yield and improves crop quality.
Disadvantages of Biofertilizers
"SLQC: Slow action, Limited shelf-life, Quality control, Specific requirements"
S: Slow action compared to chemical fertilizers; may take longer to see results.
L: Limited shelf-life and specific storage conditions are required for effectiveness.
Q: Quality control is essential; poor quality can lead to ineffective results.
C: Specific requirements for applications may limit their usability in some scenarios.
Biofertilizers NEET MCQs
Q1. For soya bean cultivation, which of the following is used as a biofertilizer?
Nostoc
Azospirillum
Rhizobium
Azotobacter
Correct answer: 3) Rhizobium
Explanation:
Biofertilizers: It is a substance containing living microorganisms. When applied to seeds, plant surfaces, or soil, these bacteria colonize the rhizosphere or interior of the plant, promoting growth by increasing the supply or availability of primary nutrients to the host plant. Biofertilizers supplement nutrients through natural nitrogen fixation processes. Examples: Rhizobium, Azotobacter, Blue-green algae, Azospirillum.
Because a biofertilizer is technically alive, it can symbiotically bond with plant roots. Microorganisms involved could easily and safely convert complex organic material into simple compounds that can be easily taken up by plants. The function of microorganisms is long-lasting, which improves soil fertility. It preserves the soil as a natural habitat.
Rhizobium: Rhizobium has commensal relationships with leguminous legumes such as soybeans. Symbiosis is defined as "living together." (G. syn = together, bios = existence. All interactions in which two species truly exist together without consideration for advantage or harm to the participants are considered symbiotic. Plants cannot absorb air nitrogen directly; instead, they require it in liquid forms. Rhizobium is a bacteria that can transform atmospheric nitrogen into a soluble state. However, Rhizobium cannot produce its sustenance. As a result, it resides in the roots of gram, peas, moong, beans, and other legumes and gives nitrogen to them. The majority of legumes (dals) are derived from leguminous vegetation. In exchange, the bacteria receive sustenance and protection from the vegetation.
Nostoc: Some blue-green phytoplankton are capable of nitrogen-fixing. Nitrogen is fixed in blue-green algae by specialized cells known as heterocysts. They transform nitrogen from the atmosphere into nitrogenous molecules such as amino acids and nitrates. These nutrients make the earth more fertile. As a result of nitrogen fixation, blue-green phytoplankton enhance soil productivity. Examples of blue-green algae that fix nitrogen are Nostoc.
Azotobacter: It is a nitrogen-fixing free-living bacterium that is widely used in wheat, rice, cotton, and sugarcane crops.
Azospirillum: Azospirillum is an aerobic-associated symbiotic nitrogen-fixing organism that develops a symbiotic association with the roots of grasses. It is used in the production of sorghum and pearl millet.
Hence, the correct answer is option 3) Rhizobium.
Q2. In order to supplement the cattle's nutritional needs, especially that of milking bovines, which bio-fertilizer is used?
Azotobacter
Azospirillum
Rhizobium
Azolla
Correct answer: 4) Azolla
Explanation:
Azolla: Azolla is also known as mosquito ferns or aquatic ferns. Their form is extremely reduced and specialized, resembling duckweed or some mosses rather than the typical fern. In addition to being used as animal feed, human food, medicine, and a water purifier, it can also be used as animal feed. As a bio-fertilizer, it improves soil fertility and boosts crop yields.
Azotobacter: Cysts are the resting stages of free-living diazotrophic bacteria. Most of the time, it is found in neutral to alkaline soils, in aquatic environments, and on plants. Several metabolic functions are available to it, including the ability to fix atmospheric nitrogen by converting it to ammonia.
Azospirillum: One of the most studied plant growth-promoting bacteria (PGPB) is Azospirillum. This is a common model for plant-bacterial interactions. There are at least 22 species of Azospirillum, with Azospirillum brasilense being the most widely known
Rhizobium: Rhizobium is a genus of bacteria that produces root nodules on plants. Legumes live in symbiosis with these bacteria
Hence, the correct answer is option 4) Azolla.
Q3. An organism used as a biofertilizer for raising soyabean crops is
Azotobacter
Azospirillum
Rhizobium
Nostoc
Correct answer: 3) Rhizobium
Explanation:
Rhizobium is a significant bio-fertilizer that is also used for symbiotic nitrogen fixation with leguminous plants. Symbiosis leads to an increase in nitrogen levels in the soil, which is one of the key factors in the general fixation of nitrogen. Application of Rhizobium inoculums to crops is an agronomic activity that is currently undertaken to provide a sufficient supply of nitrogen for the growth of healthy plants and agricultural productivity in a sustainable way.
Hence the correct answer is Option 3) Rhizobium.
Also Read:
FAQs on Biofertilizers
What is a biofertilizer with an example?
Biofertilizers are living microorganisms that enhance plant nutrition and growth when applied to seeds, plant surfaces, or soil. Unlike chemical fertilizers, which directly provide nutrients, biofertilizers work by increasing the availability of nutrients already present in the soil or by fixing atmospheric nitrogen. They are environmentally friendly and promote sustainable agriculture. Rhizobium, Azotobacter, Azospirillum, and blue-green algae (BGA) are examples for biofertilizers.
What are the types of biofertilizers?
Bacteria: The symbiotic bacteria make an association with crop plants through forming nodules in their roots. The free living do not form associations but fix atmospheric nitrogen. Examples: Rhizobium, Azotobacter, Azospirillum, Blue-green algae (Anabaena).
Phosphate-solubilizing biofertilizers: It helps to take insoluble phosphates available to plants. Examples: Pseudomonas, Bacillus, Aspergillus.
Mycorrhizal fungi: Symbiotic fungi that increase absorption of phosphorus and water.
Organic Matter: It includes compost and vermicompost, essential for nutrient supply and improving the soil structure and fertility.
What are the advantages of biofertilizers?
Biofertilizers have served a great purpose in sustainable agriculture as well towards a better environment.
It is eco-friendly as it reduces dependence on chemical fertilizers and pollution.
It helps to Improve soil fertility by enhancing nutrient cycling and soil microbial activity.
It is less expensive than the chemical fertilizers as it is required in less amount compared to synthetic fertilizers.
It gives better crop yield and quality.
What are the disadvantages of biofertilizers?
Although biofertilizers have several advantages, it has a few disadvantages:
It works slowly compared to fast-acting chemical fertilizers.
It has a shorter shelf life as microbes may lose viability if not stored properly.
Some biofertilizers show specificity i.e., they work only with certain crops.
They are sensitive to temperature and contamination, hence it is difficult to store and handle them.
Frequently Asked Questions (FAQs)
Vegetable farming and kitchen gardening have been transformed by vermicompost. Among all the fertilizers, it has produced the finest results in organic farming. Whether cultivated in containers or on raised beds, vermicompost can be used as a major fertilizer to grow a variety of fruiting, subterranean, and leafy vegetables.
Packets of biofertilizer must be kept in a cool, dry place away from heat and sunshine. The proper biofertilizer combinations must be employed. Rhizobium should only be used for the designated crop because it is crop-specific.
These fertilizers can be applied to a variety of crops, including horticultural crops, vegetables, fruit trees, forest trees, medicinal, herbal, and decorative plants, as well as legumes, cash crops, cereal crops, fodder crops, oil seed crops, and horticultural crops.
Biofertilizers work in conjunction with chemical fertilizers; they do not replace them. Only 20 to 30 percent more crops are produced as a result of using biofertilizers. Like chemical fertilizers, they do not significantly boost productivity. For particular crops, specific fertilizers are.