Question 10 of 14intermediate🔧 ApplyLong Answer5 marks

Microbes can be used to decrease the use of chemical fertilisers and pesticides. Explain how this can be accomplished.

Correct Answer

The use of chemical fertilisers and pesticides has led to significant environmental pollution. These chemicals are toxic and harmful to humans and animals, polluting soil, groundwater, fruits, vegetables, and crop plants. Microbes offer eco-friendly alternatives through biocontrol and biofertilisers.

Biocontrol refers to the use of biological methods for controlling plant diseases and pests using microbes. This approach helps avoid heavy use of toxic pesticides and insecticides. Biocontrol measures are safer as they do not pollute the environment or leave harmful residues on crops.

Biofertilisers are organisms that enrich the nutrient quality of the soil. The main sources are bacteria, fungi, and cyanobacteria. These organisms naturally enhance soil fertility without the negative impacts of chemical fertilisers.

Examples include Rhizobium bacteria that form symbiotic associations with leguminous plants, forming nodules on roots and fixing atmospheric nitrogen into organic forms. Other bacteria like Azospirillum and Azotobacter fix atmospheric nitrogen while free-living in soil, enriching nitrogen content naturally.

The increasing pressure to switch to organic farming highlights the importance of these microbial applications in sustainable agriculture, reducing chemical dependency while maintaining productivity.

Exercise: EXERCISES | Q: 10 | (Page 11)
For More Understanding

Explanation

This answer comprehensively addresses both aspects of the question - reducing chemical fertilisers through biofertilisers and reducing pesticides through biocontrol. The textbook context from Sections 8.5 and 8.6 provides all necessary information including specific examples of nitrogen-fixing bacteria (Rhizobium, Azospirillum, Azotobacter). The answer follows the 5-mark format with clear paragraph breaks and bolded key terms.

Solution Steps

  1. Step 1: Introduce the problem of chemical pollution from fertilisers and pesticides

  2. Step 2: Explain biocontrol as a method to replace toxic pesticides

  3. Step 3: Define biofertilisers and their sources (bacteria, fungi, cyanobacteria)

  4. Step 4: Provide specific examples of nitrogen-fixing microbes

  5. Step 5: Conclude with the importance of organic farming and sustainability

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