Environmental Studies · Biology

Soil Science and Fertilizers

1,509 Questions

Soil science focuses on soil formation, classification, and fertility management using fertilizers and organic amendments. Agricultural and environmental science exams heavily feature questions on biofertilizers, mycorrhiza, and phytoremediation. Practice these questions to build a strong understanding of soil nutrient cycles.

Phytoremediation techniquesOrganic soil amendmentsBiofertilizers and mycorrhizaNitrous oxide emissionsIn-situ soil remediationGreen manuring effects

Soil Science and Fertilizers Questions

Multiple choice chemistry nitrogen and sulfur nitrogen gas component of air - nitrogen nitrogen

What is the key element in soil fertilizer?

  1. Carbon

  2. Nitrogen

  3. Oxygen

  4. Neon

  5. Argon
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Nitrogen is the key element in soil fertilizer. It is essential for plant growth but plants cannot utilize atmospheric nitrogen as it is inert due to presence of triple bond. Hence, it is supplied through fertilizer.

Multiple choice chemistry nitrogen and sulfur nitrogen gas component of air - nitrogen nitrogen

Soil fertilizer contains ______ as a key element.

  1. carbon

  2. nitrogen

  3. oxygen

  4. neon

  5. argon
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Soil fertilizer contains Nitrogen as a key element.
Nitrogenous fertilizers react with moisture in the soil and produce ammonia which is converted to nitrates by soil bacteria and stored as plant food.

Multiple choice chemistry nitrogen and sulfur nitrogen gas component of air - nitrogen nitrogen

Which of the following is not a nitrogenous fertilizer ?

  1. Calcium cyanamide

  2. CAN

  3. Super phosphate of lime

  4. Urea
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
Calcium cyanamide ($CaCN _2$) is nitrogenous fertilizer.
CAN is calcium ammonium nitrate and urea $NH _2-CO-NH _2$ is also nitrogenous fertilizer.
Superphosphate of lime, $Ca(H _2PO _4) _2$ is fertilizer of phosphorous.So it's not the fertilizer of nitrogen.
Hence option C is correct.
Multiple choice zoology ecosystems decomposition in ecosystem ecosystem productivity and decomposition producers, consumers and decomposers

.......... play a very important role in  decomposition of organic matter in the soil

  1. Cat

  2. Plants

  3. Microorganisms

  4. All of the above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Micro-organisms dwell in soil. They contribute to various processes related to the soil, plants and atmosphere. One of the processes is decomposition of dead remains of plants and animals

So, the correct answer is 'micro-organisms'

Multiple choice zoology ecosystems decomposition in ecosystem ecosystem productivity and decomposition producers, consumers and decomposers

Which of these help in decomposition of organic wastes?

  1. Bacteria

  2. Fungi

  3. Earthworm

  4. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

When organic wastes such as leftover food, plant and animals waste is collected in heaps, decomposers such as bacteria, insects such as earthworms and fungi act on it and break it down. This product which is formed by this action of decomposers is called compost. This process is called composting and the compost can be used to increase the plant yield. Thus the correct answer is option D.

Multiple choice zoology ecosystems decomposition in ecosystem ecosystem productivity and decomposition producers, consumers and decomposers

Which of the following process helps in nutrient conservation?

  1. Mineralisation

  2. Immobilisation

  3. Leaching

  4. Nitrification
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Immobilization is the conversion of inorganic compounds to organic compounds by microorganisms or plants, by which it is prevented from being accessible to plants. Immobilization is the opposite of mineralization. Plants utilize minerals in inorganic form. Hence, immobilization helps in nutrient conservation.

So, the correct answer is 'Immobilization'.

Multiple choice zoology ecosystems decomposition in ecosystem ecosystem productivity and decomposition producers, consumers and decomposers

The plant parts when fully decomposed by microorganism and mixed in the soil is caIled as

  1. Litter

  2. Duff

  3. Humus

  4. All of the above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Humus is a dark-brown or black organic substance made up of decayed plant or animal matter which are fully decomposed by microorganisms like bacteria. Humus provides nutrients for plants and increases the ability of soil to retain water. It has a characteristic black or dark brown color and is organic due to an accumulation of organic carbon. 

Therefore, the correct answer is option C.

Multiple choice zoology ecosystems decomposition in ecosystem ecosystem productivity and decomposition producers, consumers and decomposers

Humus is 

  1. Dead and decayed organic matter

  2. Living matter

  3. Fertilizers

  4. Living animal, plants and microbes
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Humus is dark, organic material that forms in soil when plant and animal matter decays. When plants drop leaves, twigs, and other material to the ground, it piles up. This material is called leaf litter. When animals die, their remains add to the litter. The thick brown or black substance that remains after most of the organic litter has decomposed is called as humus. Humus contains many useful nutrients for healthy soil. 

Multiple choice zoology ecosystems decomposition in ecosystem ecosystem productivity and decomposition producers, consumers and decomposers

Which of the following process is involved in the processing of manures?

  1. The decomposition of animal excreta

  2. Plant waste

  3. Above both options are correct

  4. None of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Manure is prepared by the decomposition of animal excreta and plant waste.

So, the correct answer is 'above both options are correct'

Multiple choice zoology ecosystems decomposition in ecosystem ecosystem productivity and decomposition producers, consumers and decomposers

Which of the following statement regarding decomposition is false?

  1. Warm and moist environment favors decomposition.

  2. Decomposition rate is slower if detritus is rich in chitin and lignin.

  3. Earthworm is a detritivore.

  4. Precipitation of soluble inorganic nutrients into the soil horizon of unavailable salt is called as mineralization.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Decomposition takes part in recycling of biogeochemicals and creating space for newer generations of organisms. A number of processes are involved in decomposition. 

They are grouped into three categories- 
(i) Fragmentation of detritus carried out by earthworms, termites, millipedes etc. 
(ii) Catabolism carried out by decomposers, which secrete digestive enzymes over the detritus and change insoluble complex organic substances into  simple and soluble organic and inorganic substances. 
(iii) Leaching in which soluble substances formed during decomposition are passed to deeper layers of soil. 
The process of decomposition is favoured by warm and moist environment, because it favours growth of decomposers. 
Mineralization is the release of inorganic substances both non-mineral, example carbon dioxide and water; and minerals like calcium, magnesium, potassium, etc from organic matter.
In short, mineralisation is the process by which humus is further degraded by some microbes to release inorganic substances.
Thus, the correct answer is option D.

Multiple choice zoology ecosystems decomposition in ecosystem ecosystem productivity and decomposition producers, consumers and decomposers

Decomposition rate is slow, if detritus is rich in

  1. Nitrogen

  2. Humus

  3. Sugars

  4. Lignin and chitin

  5. Water soluble substances
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Decomposition is the process of breaking down organic matter into simple inorganic matter. Under same environmental conditions, the rate of decomposition various due to change in composition of detritus. If detritus is rich in lignin and chitin, the decomposition rate is slow. If detritus is rich in nitrogen, the decomposition rate is relatively high.

Thus, the correct answer is 'Lignin and chitin.'