Soil Organic Matter MCQs Quiz 9 Posted on May 3, 2026Author agropublishers 0 1. Which soil component most significantly influences nutrient availability, structure, and biological activity? Soil organic matter Silt fraction Sand fraction Soil water 2. Nitrogen mineralization is best defined as the microbial conversion of organic nitrogen into _______ Gaseous nitrogen exclusively Ammonia Stable organic forms NH₄⁺, NO₃⁻ 3. Which organic amendment is most effective in long-term improvement of cation exchange capacity of a sandy soil? Raw poultry manure Fresh FYM Well-decomposed vermicompost Fresh green biomass 4. Soil carbon loss is most accelerated under ________________ Increased soil disturbance and oxygen exposure High clay content Cool climate Addition of organic matter 5. Which composting method involves turning the pile regularly to maintain aerobic conditions and achieve rapid decomposition? Aerobic windrow composting Vermicomposting Anaerobic digestion Pit composting 6. Conversion of inorganic nutrients into microbial biomass is called ______________ Mineralization Denitrification Immobilization Nitrification 7. Under aerobic conditions, main gas released during decomposition is _________ Nitrogen Hydrogen Oxygen Carbon dioxide 8. Which process leads to the formation of chemically complex, recalcitrant organic compounds that resist microbial breakdown? Immobilization Humification Leaching Mineralization 9. Vermicompost enhances soil aggregation primarily through ______________ Reducing overall soil microbial activity Increasing the sand fraction in soil Production of polysaccharides and other microbial binding agents Increasing soil acidity to bind particles chemically 10. In soil, ___________________ regulates decomposition rate CEC ratio Soil moisture ratio pH ratio C:N ratio Loading … Question 1 of 10
