All Free Agriculture MCQs with Answers

• A. Sand stone
• B. Igneous
• C. Classics
• D. Greis

Explanation: Weathering breaks older rocks into mineral fragments that are transported and deposited to form clastic sedimentary rocks.

• A. None of the above
• B. Basic
• C. Both a & b
• D. Acidic

Explanation: Rhyolite is the fine-grained volcanic equivalent of granite and is rich in silica, making it an acidic or felsic rock.

• A. 5.0 to 6.5
• B. 7.5 to 8.5
• C. 6.5 to 7.5
• D. 8.5 to 9.5

Explanation: Most soils in arid and semi-arid Sindh are alkaline because evaporation concentrates carbonates and other basic salts, commonly giving a…

• A. Zone of atmosphere
• B. Zone of ozone
• C. Zone of earth crust
• D. Zone of water

Explanation: The lithosphere is Earth’s rigid outer shell, consisting of the crust and the uppermost solid mantle.

• A. 6 billion years
• B. 4 billion years
• C. 1 billion years
• D. 4.5 billion years

Explanation: Radiometric dating of meteorites and the oldest terrestrial materials places Earth’s age at approximately 4.54 billion years…

• A. Wind
• B. Fire
• C. Water
• D. Atmosphere

Explanation: Thal and Cholistan are dry, sparsely vegetated regions where strong winds loosen and transport exposed soil, causing severe wind erosion.

• A. Pakistan
• B. Canada
• C. Both b & c
• D. Alaska

Explanation: Histosols are organic soils formed from accumulated plant material, especially in cold, wet, poorly drained regions.

• A. >4%
• B. 5%
• C. >10%
• D. <20%

Explanation: Mineral soils are conventionally distinguished from organic soils by having less than 20% organic material in basic soil classification.

• A. 39.0
• B. 40.0
• C. 41.0
• D. 38.0

Explanation: Potassium has a standard atomic weight of approximately 39.10, conventionally rounded to 39.0 in fertilizer calculations.

• A. CaO
• B. Ca(free cation
• C. Ca
• D. None of the above

Explanation: Plants absorb calcium mainly as the dissolved Ca2+ ion, not as calcium oxide or elemental calcium.

• A. NO3
• B. NH4
• C. None of the above
• D. Both a & b

Explanation: Plants commonly absorb inorganic nitrogen in both nitrate form, NO3−, and ammonium form, NH4+.

• A. SAR is >13
• B. EC is 8.5
• C. All the above

Explanation: A sodic soil is identified by excessive exchangeable sodium, commonly represented by SAR above 13 or ESP above 15.

• A. 7.5
• B. 12
• C. 7
• D. 14

Explanation: Most Pakistani soils are slightly to moderately alkaline because of arid and semi-arid conditions, with a commonly cited pH around 7.5 or…

• A. Solution complex
• B. Chelate
• C. Complex ion
• D. All the above

Explanation: When two or more donor groups of one ligand bind the same metal ion, they form a ring structure called a chelate.

• A. Ziebig
• B. Niel
• C. Kohler
• D. Darcy

Explanation: Darcy established the law describing water movement through porous media, including vertical flow in soil.

• A. Macro pores
• B. Micro pores
• C. Meso pores
• D. None of the above

Explanation: Gravitational water drains through the larger channels of soil, so it is mainly found in macropores.

• A. Ionic bonding
• B. Isomorphic substitution
• C. Covalent bonding
• D. pH change

Explanation: Isomorphic substitution replaces one ion in a clay mineral lattice with another of similar size, creating a permanent charge that does not…

• A. Mgº
• B. Kº
• C. NH2
• D. Both b & c

Explanation: Smectite can retain or fix potassium ions between its expanding layers, although potassium fixation is generally stronger in illite and…

• A. Vander walls forces
• B. Covalent bond
• C. Wire bond
• D. None of the above

Explanation: Van der Waals attraction between very fine clay particles contributes to their cohesive and slippery behavior, especially when water films…

• A. Jinney
• B. Simonson
• C. Newton
• D. Ziking

Explanation: Simonson described soil-forming processes as additions, losses, translocations and transformations.