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

Which one of the following is a balanced fertilizer for plants?

  1. Urea

  2. Ammonium sulphate

  3. Nitrates

  4. Compost
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Compost is considered a balanced fertilizer because it provides a diverse mixture of organic matter and multiple essential macronutrients and micronutrients. Chemical fertilizers like urea or ammonium sulphate are typically high in only a single nutrient, such as nitrogen.

Multiple choice

Which of the following fertilizers has the highest percentage of nitrogen?

  1. Calcium ammonium nitrate

  2. Ammonium sulphate

  3. Calcium nitrate

  4. Urea
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Urea (CO(NH2)2) contains approximately 46% nitrogen by mass, which is the highest among all common nitrogen fertilizers. Calcium ammonium nitrate contains about 27-28% nitrogen, ammonium sulphate contains 21%, and calcium nitrate contains about 15-17%. The high nitrogen content makes urea an efficient and economical choice for farmers.

Multiple choice

Which of the following can be the reasons of soil acidification?

  1. Heavy rainfall
  2. Use of fertilizer
  3. Shifting cultivation

  1. 1 and 2 only

  2. 1 and 3 only

  3. 2 and 3 only

  4. 1, 2 and 3
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Increase of concentration of hydrogen ions in the soil is known as soil acidification. The main cause of soil acidification is inefficient use of nitrogen fertilizer. Heavy rainfall may also lead to soil acidification as the bases in soils are washed away. Shifting cultivation does not lead to soil acidification, although it leads to generating infertile soil. 

Multiple choice

In ecology, the term “standing crop” signifies

  1. total biomass of whole organic matter

  2. total biomass of heterotrophs

  3. total area covered by crops

  4. total increase in crop production by use of fertilizers
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

In ecology, the term “standing crop” signifies the total biomass of whole organic matter of an ecosystem.

Multiple choice

Leguminous plants help in the replenishment of the soil with

  1. oxygen

  2. nitrogen

  3. hydrogen

  4. carbon dioxide

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

Rhizobium is present in the root nodules of leguminous plants. These bacteria convert atmospheric nitrogen into simpler nitrogen compounds that can be easily absorbed by plants. Hence, it is the correct answer.

Multiple choice

Which of the following statements is incorrect?

  1. Loose soil particles have more air spaces

  2. Loose soil particles hold less water for longer duration

  3. Loose soil helps roots to penetrate deep through the layers of soil

  4. Loose soil promotes the growth of useful soil microbes

  5. While turning the soil during ploughing, nutrient-rich soil is brought up from lower level of soil
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Correct Answer: Loose soil particles hold less water for longer duration

Multiple choice

_____ is used for the reclamation of acidic soil.

  1. Sulphur

  2. Gypsum

  3. Lime

  4. Calcium Chloride

  5. Ferrous Sulphate
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Lime (calcium carbonate or calcium oxide) is used to reclaim acidic soils because it neutralizes soil acidity by raising the pH level. The calcium in lime replaces hydrogen and aluminum ions, making nutrients more available to plants. Sulphur would make soil more acidic, while Gypsum is used for sodic/alkaline soils, not acidic ones.

Multiple choice

The pH value of a soil measures its

  1. fertility rate

  2. iron and lime content

  3. water retention

  4. acid content
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Soil pH measures the acidity or alkalinity of soil on a scale of 0-14, with 7 being neutral. It indicates the concentration of hydrogen ions in the soil solution, which determines acid content. pH affects nutrient availability and microbial activity. Fertility, iron-lime content, and water retention are important soil properties but are not measured by pH.