Soil Organic Matter MCQs Quiz 6 Posted on May 3, 2026Author agropublishers 0 1. Soil organic matter increases water holding capacity primarily due to the presence of ___________ Organic colloids Sand particles Gravels Large silt particles 2. Nitrogen mineralization results in the release of _________ nitrogen Gaseous form only Inorganic nitrogen Ammonium form only Organic nitrogen 3. Which process transforms unstable organic matter into stable, resistant compounds? Mineralization Humification Leaching Immobilization 4. Which component most strongly contributes to the formation of stable soil organic matter (humus)? Lignin and its derivatives Proteins Nucleic Acid Sugars 5. Soil organic matter accumulation is highest in__________ Sandy soils Hot soils Dry soils Cold soils 6. Soil organic matter improves soil resilience primarily by _________ Enhancing structural stability Facilitating vertical nutrient movement Hardening the soil Increasing erosion 7. Immobilization is the process by which nutrients are converted from _____________ to ___________ Solid → gas Organic → inorganic Inorganic → organic Liquid → gas 8. Which factor primarily controls the rate of humification? Quality and composition of organic inputs Soil depth Water content Rock type 9. Which condition shifts the balance toward carbon loss from soil? Frequent aeration and disturbance Organic additions Clay content Low temperature 10. Soil fertility depends most strongly on ___________ Water availability Sand content Silt content Soil organic matter content Loading … Question 1 of 10
