Free Soil Science MCQs with Answers

• A. Extremely high
• B. Extremely low
• C. Very little
• D. None of these

Explanation: Colloids are extremely small particles, so a given mass exposes a very large total surface area.

• A. From the field with immediate application of fertilizer or amendments
• B. None of these
• C. Boundaries of the field
• D. Field with upper white layer of salts

Explanation: Representative soil samples should not be taken from fertilizer or amendment application spots, salt-affected patches, or field boundaries…

• A. Rain splash rill erosion
• B. Stream bank erosion
• C. Sheet erosion
• D. Gully erosion

Explanation: Sheet erosion removes a relatively uniform thin layer of soil across the surface through flowing water.

• A. 12.5 % -12.5 % - 75%
• B. 64.7 % - 27.4 % - 7.9 %
• C. none of A & B
• D. 7.9% - 27.7 % - 64.4

Explanation: The commonly cited crustal proportions are approximately 64.7% igneous, 27.4% metamorphic, and 7.9% sedimentary rocks.

• A. 64 %
• B. 79 %
• C. 75 %
• D. 73 %

Explanation: Oxygen makes up about 46.6% and silicon about 27.7% of the Earth’s crust by weight, giving a combined value near 74%, conventionally…

• A. 23 %
• B. 2.3 %
• C. 17 %
• D. 1.7 %

Explanation: Potassium constitutes about 2.3% of the Earth’s crust by weight. The other percentage choices are much too high for potassium’s crustal…

• A. Provides energy for the microbial
• B. Maintains the productivity of soil
• C. Gives structure to the soil
• D. All of these

Explanation: Soil organic matter feeds microorganisms, releases and stores nutrients, improves aggregation and structure, and supports long-term soil…

• A. both A & B
• B. Humic acid & Fulvic acid
• C. Hymatomelanic acid & Humin
• D. None of theseGeology

Explanation: Humic substances are commonly fractionated into fulvic acid, humic acid and humin; hymatomelanic acid is also recognised as a fraction of…

• A. Ca
• B. N
• C. Mg
• D. None of the above

Explanation: Nitrogen is an essential part of amino acids and therefore proteins, and it forms the nitrogenous bases of nucleic acids.

• A. An area of soil from root surface to 5 cm
• B. Area within the roots
• C. Root surface
• D. All of them

Explanation: The rhizoplane is the actual root surface, including the immediate surface zone where roots interact with soil microorganisms.

• A. Composition of molten magma
• B. Depth of molten magma
• C. Both A and B
• D. Composition can not be determined.

Explanation: The mineral composition of an igneous rock primarily reflects the chemical composition of the molten magma from which it crystallises.

• A. Gleization
• B. The correct option is not present aboveHire Grant Writers
• C. Laterization
• D. Lessivage

Explanation: The general process of mixing soil horizons or soil materials is called pedoturbation, and that term is absent from the options.

• A. 74 %
• B. 54 %
• C. 62.5 %
• D. 34%

Explanation: The Walkley-Black method oxidises only about 74 to 77 percent of the organic carbon, so a correction factor is commonly applied.

• A. 110 0C
• B. 120 0C
• C. both A and B
• D. 105 0C

Explanation: For routine gravimetric soil moisture analysis, samples are commonly dried to constant weight at about 105°C.

• A. Mollisols
• B. Arable soils
• C. Histosols
• D. Non-arable soils

Explanation: Cultivation commonly removes or incorporates the surface organic layer, so a distinct O horizon is generally absent in arable soils.

• A. Bacteria
• B. both A & B
• C. Fungi
• D. None of the above

Explanation: Vesicular arbuscular mycorrhiza is a symbiotic association formed by fungi with plant roots.

• A. Plasma
• B. Quartz
• C. Carbon
• D. None of these

Explanation: ICP-AES uses an inductively coupled plasma, usually an argon plasma, to reach the extreme temperatures needed to excite atoms and produce…

• A. 20 mg of ca2+
• B. All of the above
• C. 9 mg of Al3+
• D. 12 mg of Mg2+

Explanation: Equivalent amounts are calculated using atomic or molecular mass divided by valency: Ca²⁺ is about 20 mg, Mg²⁺ about 12 mg, and Al³⁺ about…

• A. Aristotle et al.
• B. Hiltner
• C. A.Q khan
• D. Helium. S. Denial

Explanation: Lorenz Hiltner introduced the term rhizosphere for the soil region influenced by plant roots.

• A. Shafiq Khalil et al.
• B. Theodore Saussure
• C. Dr. Muhammad Sharif et al.
• D. C. Sprengel

Explanation: C. Sprengel was among the first to establish the essential role of mineral elements such as potassium, calcium, magnesium and phosphorus…