Biofertilizers: Types & Uses – Old Year Questions

1. Which of the following is/are used as biofertilizers?

1. Azolla
2. Blue-green algae
3. Alfalfa

Choose the correct answer by the given codes :

(a) only 2
(b) 1 and 2
(c) 1 and 3
(d) 1, 2 and 3

[I.A.S. (Pre) 1994, U.P.P.C.S. (Pre) 2002 , U.P.P.C.S. (Pre) 2001]


2. Which of the following is used as a Biofertilizer?

(a) Rhizobium
(b) Blue-green algae
(c) Azolla
(d) All of these

[Chhattisgarh P.C.S. (Pre) 2019,Uttarakhand P.C.S. (Mains) 2002]


3. Which of the following is not a nitrogen-fixing organism?

(a) Nostoc
(b) Anabaena
(c) Azotobacter
(d) Mycorrhiza

[U.P. P.C.S. (Mains) 2017]


4. Which of the following is a source of bio-fertilizer?

(a) Yeast
(b) Chlorella
(c) Azolla
(d) Mold

[U.P.P.C.S. (Mains) 2009, U.P.P.C.S. (Spl) (Mains) 2008, Uttarakhand P.C.S. (Mains) 2002]


5. The biofertilizer used as a supplementary food for the cattle, especially for milking bovines is :

(a) Azospirillum
(b) Azolla
(c) Azotobacter
(d) Rhizobium

[R.A.S./R.T.S. (Pre) 2016]


6. Nitrogen-fixing bacteria make combinations with cells of the roots of

(a) Pulses
(b) Rice
(c) Wheat
(d) Sugarcane

[U.P.P.C.S. (Pre) 2019]


7. Which of these is not correctly matched

(a) Blue-green algae – Bio-fertilizer
(b) Chrysopa – Maho-control
(c) Bio 902 – Variety of mustard
(d) Azotobacter – Bioinsecticide

[U.P.Lower Sub. (Spl.) (Pre) 2003 U.P.Lower Sub. (Spl.) (Pre) 2002]


8. Which of the following is associated with biological nitrogen fixation?

(a) Red algae
(b) Brown Algae
(c) Green algae
(d) Blue-green algae

[U.P.P.C.S. (Pre) 2019]


9. Blue-green algae are chiefly used as biofertilizers in the crop of 

(a) Wheat
(b) Gram
(c) Paddy
(d) Mustard

[U.P.P.C.S. (Pre) 2006]


10. Blue-green algae is used to supply nitrogen to –

(a) Bajra
(b) Maize
(c) Paddy
(d) Wheat

[U.P.P.C.S. (Mains) 2010]


11. Which one of the following is not correctly matched?

Nitrogen-fixing agent  Crop
Blue-green algae Paddy
Rhizobium Leguminosarum Pea
Azotobacter Wheat
Azolla Maize

[U.P.P.C.S. (Pre) 2017]


12. Azolla gives a good biofertilizer when mixed with –

(a) Blue-green algae
(b) Bone meal
(c) Cow dung
(d) Urea

[Uttarakhand P.C.S. (Pre) 2007]


13. Azolla is often used as a biofertilizer because it is associated with –

(a) Blue-green algae
(b) Red algae
(c) Fungus
(d) Moss

[U.P.P.C.S. (Mains) 2011]


14. Azolla is –

(a) Aquatic Fern
(b) Aquatic algae
(c) Aquatic bacteria
(d) None of these

[U.P. U.D.A./L.D.A. (Spl.) (Mains) 2010]


15. Aquatic Fern, which is used as a biofertilizer, is

(a) Salvinia
(b) Azolla
(c) Marsilia
(d) Pteridium

[U.P.R.O./A.R.O. (Mains) 2014]


16. Which of the following microorganisms are used as biofertilizers?

(a) Virus
(b) Fungi
(c) Protozoa
(d) Cyanobacteria

[U.P. R.O./A.R.O. (Mains) 2016 U.P. P.C.S. (Mains) 2012]


17. Which of the following is phosphatic biofertilizer?

(a) Rhizobium
(b) Blue-green algae
(c) Azolla
(d) Vascular Arbuscular Mycorrhiza

[U.P. B.E.O. (Pre) 2019]


18. What is the use of biochar in farming?
1. Biochar can be used as a part of the growing medium in vertical farming.
2. When biochar is a part of the growing medium, it promotes the growth of nitrogen-fixing microorganisms.
3. When biochar is a part of the growing medium, it enables the growing medium to retain water for a longer time.
Which of the statements given above is/are correct?

(a) 1 and 2 only
(b) 2 only
(c) 1 and 3 only
(d) 1, 2 and 3

[I.A.S. (Pre) 2020]


19. The capability of nitrogen use efficiency can be increased in crop production by

(a) Use of split application
(b) Use of nitrogen inhibitors
(c) Using the slow release of nitrogen fertilizer
(d) All of the above.

[U.P.P.C.S. (Pre) 2009]


20. Which bacteria is responsible for nitrogen fixation in soyabean?

(a) Rhizobium leguminosarum
(b) Rhizobium japonicum
(c) Rhizobium fagioli
(d) Rhizobium traitolai

[U.P.P.C.S. (Pre) 2006]


21. Leg-haemoglobin is found in –

(a) Human blood
(b) Rabbit blood
(c) Legume root nodules
(d) Chicken blood

[U.P.P.C.S. (Mains) 2005]