Soil Organic Matter MCQs Quiz 8 Posted on May 3, 2026Author agropublishers 0 1. The high water-holding capacity of soils rich in SOM is mainly attributed to __________ Hydrophobic nature of silt particles Coarse particle fraction Macropore dominance Hydrophilic nature of organic colloids 2. In soil, humus is __________ part of organicm matter Stable Mineral Easily decomposed Inorganic 3. Breakdown of organic matter into simpler substances is known as ____________ Leaching Aggregation Decomposition Humification 4. Vermicompost improves soil porosity primarily because it ___________________ Promotes stable macroaggregate formation Reduces root penetration Creates a hard pan in the subsoil Adds fine sand particles to the soil 5. Carbon fraction of soil organic matter is known as ______________________ Total organic matter Humus carbon Soil organic carbon Inorganic carbon 6. Soil organic matter most likely to accumulate due to slow decomposition in ___________ climate Equatorial climate Arid dry climate Cold climate Hot tropical climate 7. Easily decomposable fraction of Soil Organic Matter is ___________ Passive pool Stable pool Humus Labile fraction 8. How does adequate soil organic matter increase soil resilience to environmental stress? By improving structural stability and aggregation By increasing nutrient sink By compacting soil By increasing erosion risk 9. Which factor plays the most critical role in maintaining long-term soil fertility? Soil Structure Soil organic matter content Soil moisture Soil texture 10. A major contribution of farmyard manure (FYM) to soil organic matter (SOM) is_____________- Reduction in microbial biomass Rapid nutrient release only Increase in labile and stable carbon pools Decrease in soil porosity Loading … Question 1 of 10
