All Free Agriculture MCQs with Answers

• A. Humification
• B. Horizonation
• C. Illuviation
• D. Calcification

Explanation: Humification is the biological and chemical transformation of raw plant and animal residues into relatively stable humus.

• A. Man and Animals
• B. All of these
• C. Micro- organisms
• D. Higher Plants and Roots

Explanation: Biological weathering is caused by living agents, including humans and animals, plant roots, and microorganisms.

• A. Both a and b
• B. 45.5 mol/L
• C. 55.5 mol/L
• D. none of these

Explanation: One litre of water weighs about 1000 g, and the molecular mass of H₂O is about 18 g/mol, giving 1000 ÷ 18 ≈ 55.5 mol/L.

• A. 1% or less of soil volume
• B. 10% or less of soil volume
• C. 20% or less of soil volume
• D. 30% or less of soil volume

Explanation: Although root occupancy varies with crop, depth and soil conditions, roots generally occupy 1% or less of the total soil volume.

• A. Urea
• B. Ammonium sulphate
• C. Ammonium nitrate
• D. Calcium ammonium nitrate

Explanation: Ammonium sulphate produces the greatest residual acidity because nitrification of its ammonium releases acidity, while its sulphate…

• A. Saline-sodic soils
• B. Sodic soils
• C. Acid soils
• D. Saline soilsSoil

Explanation: Zinc is generally more soluble and available in acid soils, whereas increasing soil pH, especially in sodic conditions, promotes its…

• A. Liebig
• B. Baussingault
• C. Winogrdsky
• D. Hiltner

Explanation: Lorenz Hiltner introduced the term rhizosphere for the soil region directly influenced by plant roots and their associated microorganisms.

• A. L-Value
• B. E-Value
• C. a-Value
• D. A-Value

Explanation: The E-value estimates soil phosphorus in equilibrium with the soil solution through a chemical or isotopic approach and does not require…

• A. 2.50 %
• B. 3.50 %
• C. 4,50 %
• D. 5.5 %

Explanation: Under the Fertilizer Control Order, DAP may contain a maximum of 2.5% total nitrogen in the form of urea.

• A. Fundamentals of soil
• B. Essenttials of soil sciences
• C. The nature and properties of soil
• D. The mechanics of soilSoil

Explanation: Nyle C. Brady is associated with the standard soil-science textbook The Nature and Properties of Soils, commonly used for introductory…

• A. Diphenylamine indicator
• B. Mixed indicator
• C. Both a and b
• D. None of the above

Explanation: In the Walkley-Black method, organic carbon is oxidized with potassium dichromate and the excess dichromate is titrated using…

• A. Clay minerals
• B. Amorphous silicates
• C. All of the above
• D. Iron and aluminiumoxides

Explanation: Clay minerals, amorphous silicates and iron- and aluminium oxides are all secondary minerals formed through weathering or alteration of…

• A. 4:1-8:1
• B. 10:1-15:1
• C. 15:1-20:1
• D. N0ne of the above

Explanation: Microbial biomass generally has a C:N ratio of roughly 5:1 to 15:1, depending on the microbial group and conditions.

• A. Regur
• B. Ragour
• C. Montmorillosol
• D. Regosol

Explanation: Regur, or black cotton soil, is a dark calcareous soil rich in expanding montmorillonitic clay.

• A. cm/s
• B. cm2/s
• C. cm2
• D. s/cm

Explanation: Diffusivity has dimensions of length squared divided by time because it describes how rapidly a concentration or moisture gradient…

• A. Topo sequence
• B. Catena
• C. Topography
• D. Chrono sequence

Explanation: A chrono sequence contains soils formed from the same parent material under similar relief, climate and organisms but at different stages…

• A. Area with in the roots
• B. Root surface
• C. An area of soil in from root surface to 10 cm
• D. An area of soil in immediate vicinity around root

Explanation: The rhizosphere is the narrow zone of soil immediately surrounding and influenced by plant roots.

• A. Alkali
• B. Acid
• C. Both a & b
• D. None of the above

Explanation: Humic acid dissolves in alkaline solutions but precipitates when the solution is acidified, which is the basis for separating it from…

• A. Frankia
• B. Nitrobacter
• C. Pseudomonas
• D. None of the above

Explanation: Nitrobacter oxidizes nitrite (NO₂⁻) to nitrate (NO₃⁻), completing the second stage of nitrification.

• A. None of the above
• B. Lithoshpere
• C. Atmoshpere
• D. Rhizoshpere

Explanation: The rhizosphere is the narrow zone of soil directly influenced by and in contact with plant roots.