MEVE 013: Unit 15 - Biofertilizers

-

UNIT 15: BIOFERTILIZERS

15.1 INTRODUCTION

Biofertilizers are natural fertilizers that contain living microorganisms which, when applied to seeds, plant surfaces, or soil, colonize the rhizosphere or the interior of the plant and promote growth by increasing the supply or availability of primary nutrients to the host plant. Unlike chemical fertilizers that provide nutrients directly, biofertilizers enhance the natural nutrient cycling processes of the soil. Their use leads to improved soil fertility and is a key component of sustainable agriculture.

The growing demand for eco-friendly and cost-effective alternatives to chemical fertilizers has brought biofertilizers into focus. They are important in mitigating environmental problems like soil degradation, water pollution, and greenhouse gas emissions caused by synthetic fertilizers.

15.2 OBJECTIVES

After studying this unit, you will be able to:

  • Understand the concept and importance of biofertilizers.
  • Describe the types and classification of biofertilizers.
  • Explain the mechanisms through which biofertilizers enhance soil fertility.
  • Identify different types of microorganisms used in biofertilizer production.
  • Analyze the role of biofertilizers in sustainable agriculture.

15.3 WHAT ARE BIOFERTILIZERS?

Biofertilizers are preparations that contain beneficial microorganisms such as bacteria, fungi, or algae which help in improving soil fertility by fixing atmospheric nitrogen, solubilizing phosphate, or decomposing organic matter. These microorganisms form symbiotic relationships with plants or live freely in the soil and enhance the availability of essential nutrients.

They are often used in organic farming and integrated nutrient management systems and are essential tools for sustainable agriculture. The application of biofertilizers helps reduce the need for chemical fertilizers, thus maintaining ecological balance.

15.4 CLASSIFICATION OF BIOFERTILIZERS

Biofertilizers can be classified based on the nutrient they help to mobilize or fix in the soil:

15.4.1 Nitrogen Fixing Biofertilizers

These biofertilizers fix atmospheric nitrogen into ammonia, which can be taken up by plants. Nitrogen-fixing biofertilizers are vital for crops with high nitrogen demand.

15.4.1.1 Free-living Biofertilizers

These microorganisms live freely in the soil and do not require a plant host. Examples include:

  • Azotobacter: Found in neutral to alkaline soils; used in wheat, maize, cotton, etc.
  • Clostridium: Anaerobic, found in flooded soils.
  • Cyanobacteria (blue-green algae): Fix nitrogen in rice fields.

15.4.1.2 Symbiotic Biofertilizers

These microorganisms live in association with plant roots and fix nitrogen in root nodules:

  • Rhizobium: Forms symbiotic relationships with legumes.
  • Frankia: Associates with non-leguminous plants like Casuarina.

15.4.1.3 Associative Symbionts

These form loose associations with plant roots. Examples include:

  • Azospirillum: Found in cereals and grasses; improves root development and nutrient uptake.

15.4.2 Phosphorus Contributing Biofertilizers

Phosphorus is essential for plant growth but often becomes insoluble in soil. These biofertilizers help mobilize phosphorus.

15.4.2.1 Phosphate Solubilizers

These microorganisms secrete organic acids to convert insoluble phosphates into soluble forms:

  • Bacillus megaterium
  • Pseudomonas striata
  • Aspergillus and Penicillium (fungi)

15.4.2.2 Phosphate Absorbers (Mycorrhizae)

  • Arbuscular Mycorrhizal Fungi (AMF): Form associations with plant roots and increase phosphorus uptake.
  • They also help in the uptake of micronutrients like zinc and copper.

15.4.3 Organic Matter Decomposers

These biofertilizers degrade complex organic materials into simpler substances, improving nutrient availability:

  • Cellulolytic bacteria and fungi: Decompose plant residues.
  • Actinomycetes: Break down tough organic materials.
  • Trichoderma: Also acts as a biocontrol agent against soil-borne pathogens.

15.5 ADVANTAGES OF BIOFERTILIZERS

  • Improve soil structure and fertility.
  • Enhance nutrient availability and uptake.
  • Promote root and shoot growth.
  • Environmentally friendly and non-toxic.
  • Cost-effective and sustainable.
  • Improve plant tolerance to stress (drought, salinity).

15.6 APPLICATION METHODS

  • Seed Treatment: Seeds are coated with biofertilizer slurry before sowing.
  • Soil Application: Biofertilizer is mixed with compost and spread in the field.
  • Seedling Root Dip: Seedlings are dipped in a solution of biofertilizer before transplanting.

15.7 CHALLENGES IN BIOFERTILIZER USAGE

  • Lack of awareness among farmers.
  • Inadequate quality control and shelf-life.
  • Compatibility issues with chemical inputs.
  • Storage and transportation issues.
  • Specificity to soil and crop types.

15.8 FUTURE PROSPECTS

  • Development of genetically improved strains.
  • Nano-formulated biofertilizers for controlled release.
  • Use of consortia (mixed cultures) for multiple nutrient support.
  • Integration with precision agriculture.

15.9 LET US SUM UP

Biofertilizers are biological substances that enhance nutrient availability and soil fertility using beneficial microorganisms. They are classified into nitrogen fixers, phosphorus solubilizers, and organic matter decomposers. Their use in sustainable agriculture is gaining prominence due to ecological and economic benefits. Though challenges remain in adoption and effectiveness, innovations in biotechnology continue to improve their efficiency.

15.10 KEY WORDS

  • Biofertilizer-A substance containing living microorganisms that enhance plant nutrient availability.
  • Rhizobium-A nitrogen-fixing bacterium that forms root nodules in leguminous plants.
  • Mycorrhiza-Fungi that form symbiotic associations with plant roots to enhance phosphorus uptake.
  • Phosphate Solubilizer-Microorganisms that convert insoluble phosphates into soluble forms.
  • Azospirillum-An associative nitrogen-fixing bacterium for non-legumes.
  • Trichoderma-Fungi used for organic matter decomposition and disease control.
  • Seed Inoculation-Technique of coating seeds with biofertilizer before sowing.
  • Sustainable Agriculture-Agricultural practices that preserve environmental health and economic viability.

Comments

Post a Comment

Popular Posts

Jcert Class 8 Daffodil Chapter 1a: The Naive Friends Solutions

-
Chapter 1a : The Naive Friends Answer the following questions: 1. Which questions made Keshav and Shyama curious about the egg? Ans.         How did the chick come out? How big would the eggs? How many? What colours would they? What did they eat? Such types of questions made Keshav and Shyama curious about the egg. 2. What three things did the children do to protect the eggs? Ans.         The children done three things are: (i)          Adjustment of food. (ii)        Adjustment of water. (iii)      Adjustment of roof. 3. Why did Keshav think of making a cushion for the eggs? Ans.         When Keshav saw the egg on direct sun light, he thaught making a cushion for the eggs. 4. What excuse did Keshav give for not showing the eggs to Shyama? Ans.     ...
Read more

Jcert Class 8 भाषा मंजरी Chapter 3 मित्रता Solutions

-
अध्याय - 3 : मित्रता 1. आप किस प्रकार कह सकते हैं कि मित्रों के चुनाव की उपयुक्तता पर हमारे जीवन की सफलता निर्भर करती है? उ. मित्रों के चुनाव की उपयुक्तता पर हमारे जीवन की सफलता निर्भर करती है क्योंकि संगति का गुप्त प्रभाव हमारे आचरण पर पड़ता है और यदि हमें अच्छी संगति, अच्छे मित्र मिलते हैं तो वे हमें सफलता की ओर ले जाते हैं जबकि बुरी संगति हमारे जीवन को खाक में मिला देती है।  2. 'विश्वासपात्र मित्र जीवन की एक औषध है।' आशय स्पष्ट कीजिए। उ. 'विश्वासपात्र मित्र जीवन की एक औषध है'- ऐसा इसलिए कहा गया है कि यदि हमें विश्वासी मित्र मिल गया तो हम अपने जीवन में चाहे जैसा भी कदम उठाएँ, उस कदम की आलोचना करके वह हमें सही दिशा की ओर उन्मुख करेगा। हम अपनी गलती रूपी बीमारी को उसकी आलोचना रूपी औषधि से दूर कर सकेंगे।  3. मित्र का चुनाव करते समय हमें किन बातों का ध्यान रखना चाहिए? उ. मित्र का चुनाव करते समय हमें निम्नलिखित बातों का ध्यान रखना चाहिए हमारे अच्छे विचारों (संकल्पों) को दृढ़ करने वाला हो। हमें दोषों और त्रुटियों से बचाए। हमारे सत्य, पवित्रता ...
Read more

Jcert Class 8 भाषा मंजरी Chapter 8 अमरूद का पेड Solutions

-
अध्याय - 8 : अमरूद का पेड 1. लेखक को क्यों लगता है कि इन सब पिछड़े खयालातों का हमारे घर में गुजर नहीं हो सकेगा। उ. अमरूद के पेड़ को देखकर सबसे पहले बाबू कन्हैयालाल की बूढ़ी पत्नी ने एक दिन टोका कि पश्चिम की तरफ अगर मकान का मुखड़ा हो और सामने ही अमरूद का पेड़ तो 'राम-राम बड़ा अशुभ होता है और माँ के चेहरे पर थोड़ा-सा भय दिखा पर लेखक को विश्वास था कि इन सब पिछड़े खयालातों का हमारे घर में गुजर नहीं हो सकेगा क्योंकि उसके घर के लोग आधुनिक विचारधारा के थे उसकी माँ सत्याग्रह के दिनों में अजमेर में लम्बा जेल कर चुकी है। पिताजी खुद राजनैतिक सामाजिक उदारता वाले आदमी थे। बुआ ने विवाह नहीं किया था, पढ़ने-लिखने में ही अपनी सम्पूर्ण जिन्दगी लगा दी और समाज कोई चुनौती देने का साहस नहीं कर सका। साथ ही परिवार के सभी लोगों में पिछड़ेपन के प्रति भर्त्सना का भाव था। 2. अमरूद के पेड़ की छाया किस प्रकार लेखक को उनके भाई-बहनों के साथ जोड़ती है ? उ. अमरूद के पेड़ की छाया लेखक को उसके भाई-बहनों के साथ जोड़ती है। वे सभी अमरूद की छाया में बेंत की कुर्सियों पर बैठ चर्चाएँ करते थे जिससे उनके बीच...
Read more