412 BENEFICIAL ACTIVITIES OF BACTERIA 



C. Material produced. 



D. Commercial use of material produced. 



2. Make a library report on the tanning of leather. 

 3. What is meant by soil exhaustion and soil renewal ? 



4. What is the importance of the decay process to agriculture ? 



5. Explain nitrification in detail. 



6. Discuss denitrification. 



7. Discuss nitrogen-fixation. Give three different ways of fixing 

 nitrogen. 



8. What is the importance of rotating crops ? Give at least four 

 reasons for rotating crops. 



9. Mention four different facts that must be considered in culti- 

 vating soil. 



10. Make out an original carbon and nitrogen cycle. 



11. Do farmers have scientific knowledge about bacteria or do they 

 depend upon their experience or on hearsay in caring for the soil ? 



12. Does the government make any effort to give farmers scientific 

 instruction in soil and crop improvement ? 



13. Discuss a balanced aquarium. 



SUPPLEMENTARY READINGS 



Gager, C. S., General Botany (P. Blakiston's Son & Co.). 

 Greaves, J. E. & E. O., Elementary Bacteriology (W. B. Saunders Co.). 

 Holman, R. M., & Robbins, W. W. A Textbook of General Botany (John 

 Wiley & Sons, Inc.). 



