Soil Science MCQs

1. What is soil? A) A natural resource composed of minerals, organic matter, water, and air B) A type of rock C) A liquid substance D) A form of energy Answer: A) A natural resource composed of minerals, organic matter, water, and air 2. Which soil horizon is known as the topsoil? A) Horizon A B) Horizon B C) Horizon C D) Horizon D Answer: A) Horizon A 3. What is ‘soil pH’? A) A measure of the acidity or alkalinity of the soil B) The amount of organic matter in the soil C) The color of the soil D) The soil’s texture Answer: A) A measure of the acidity or alkalinity of the soil 4. Which soil texture has the smallest particles? A) Clay B) Sand C) Silt D) Loam Answer: A) Clay 5. What is ‘soil erosion’? A) The removal of the top layer of soil by wind, water, or human activity B) The addition of nutrients to the soil C) The process of soil formation D) The increase in soil fertility Answer: A) The removal of the top layer of soil by wind, water, or human activity 6. Which of the following is a primary soil nutrient? A) Nitrogen B) Calcium C) Sodium D) Iron Answer: A) Nitrogen 7. What is ‘soil structure’? A) The arrangement of soil particles into aggregates B) The amount of water in the soil C) The color of the soil D) The soil’s pH level Answer: A) The arrangement of soil particles into aggregates 8. Which process involves the breaking down of rocks into smaller particles? A) Weathering B) Erosion C) Leaching D) Compaction Answer: A) Weathering 9. What is ‘soil fertility’? A) The ability of soil to provide essential nutrients for plant growth B) The density of soil particles C) The soil’s pH level D) The amount of organic matter in the soil Answer: A) The ability of soil to provide essential nutrients for plant growth 10. Which soil property is measured by the texture triangle? A) Soil texture (proportions of sand, silt, and clay) B) Soil pH C) Soil organic matter D) Soil moisture Answer: A) Soil texture (proportions of sand, silt, and clay) 11. What is ‘soil salinization’? A) The accumulation of soluble salts in the soil B) The process of soil formation C) The reduction of soil nutrients D) The removal of soil particles by wind Answer: A) The accumulation of soluble salts in the soil 12. Which soil horizon is known as the subsoil? A) Horizon B B) Horizon A C) Horizon C D) Horizon D Answer: A) Horizon B 13. What does ‘soil permeability’ refer to? A) The ability of soil to transmit water and air B) The amount of nutrients in the soil C) The soil’s color D) The pH level of the soil Answer: A) The ability of soil to transmit water and air 14. What is ‘soil compaction’? A) The process of increasing soil density by reducing pore spaces B) The addition of organic matter to the soil C) The increase in soil texture D) The reduction of soil acidity Answer: A) The process of increasing soil density by reducing pore spaces 15. Which soil type has the highest water-holding capacity? A) Clay B) Sand C) Silt D) Loam Answer: A) Clay 16. What is ‘soil organic matter’? A) Decomposed plant and animal material in the soil B) The mineral content of the soil C) The soil’s texture D) The soil’s pH level Answer: A) Decomposed plant and animal material in the soil 17. What is ‘leaching’ in soil science? A) The removal of dissolved nutrients from the soil by water B) The addition of nutrients to the soil C) The process of soil formation D) The compaction of soil particles Answer: A) The removal of dissolved nutrients from the soil by water 18. Which soil property affects plant root penetration and water movement? A) Soil texture B) Soil color C) Soil organic matter D) Soil pH Answer: A) Soil texture 19. What is the primary purpose of soil testing? A) To determine soil nutrient levels and pH for effective management B) To measure soil color C) To evaluate soil structure D) To assess soil compaction Answer: A) To determine soil nutrient levels and pH for effective management 20. Which of the following is a factor that influences soil formation? A) Parent material B) Soil color C) Soil texture D) Soil density Answer: A) Parent material 21. What is ‘soil tilth’? A) The physical condition of soil as it relates to its suitability for plant growth B) The pH level of the soil C) The amount of organic matter in the soil D) The soil’s texture Answer: A) The physical condition of soil as it relates to its suitability for plant growth 22. Which of the following is an indicator of soil erosion? A) Rills and gullies B) Increased soil organic matter C) Increased soil moisture D) Reduced soil density Answer: A) Rills and gullies 23. What is the role of ‘earthworms’ in soil health? A) They improve soil structure and increase nutrient availability B) They increase soil acidity C) They compact the soil D) They reduce soil organic matter Answer: A) They improve soil structure and increase nutrient availability 24. Which of the following is a method to prevent soil erosion? A) Planting cover crops B) Increasing soil compaction C) Removing vegetation D) Deep plowing Answer: A) Planting cover crops 25. What is ‘soil moisture’? A) The amount of water present in the soil B) The soil’s pH level C) The soil’s texture D) The amount of organic matter in the soil Answer: A) The amount of water present in the soil 26. What does ‘soil texture’ refer to? A) The size distribution of mineral particles in soil (sand, silt, clay) B) The soil’s pH level C) The amount of organic matter in the soil D) The color of the soil Answer: A) The size distribution of mineral particles in soil (sand, silt, clay) 27. What is ‘soil infiltration’? A) The process by which water enters and moves through the soil B) The removal of water from the soil C) The addition of organic matter to the soil D) The increase in soil density Answer: A) The process by which water enters and moves through the soil 28. Which of the following is a soil amendment that improves soil structure? A) Compost B) Sand C) Gravel D) Clay Answer: A) Compost 29. What is ‘soil texture triangle’ used for? A) To classify soil based on its texture (sand, silt, clay) B) To measure soil pH C) To determine soil fertility D) To assess soil moisture Answer: A) To classify soil based on its texture (sand, silt, clay) 30. What does ‘soil aeration’ refer to? A) The exchange of gases between the soil and the atmosphere B) The addition of nutrients to the soil C) The removal of soil particles D) The increase in soil density Answer: A) The exchange of gases between the soil and the atmosphere 31. Which soil horizon contains the most organic matter? A) Horizon A B) Horizon B C) Horizon C D) Horizon D Answer: A) Horizon A 32. What is ‘soil bulk density’? A) The mass of soil per unit volume, including air space B) The weight of soil per unit area C) The soil’s pH level D) The amount of organic matter in the soil Answer: A) The mass of soil per unit volume, including air space 33. Which of the following is a consequence of soil compaction? A) Reduced root growth and water infiltration B) Increased soil fertility C) Enhanced soil structure D) Increased soil aeration Answer: A) Reduced root growth and water infiltration 34. What is ‘soil texture’ determined by? A) The proportion of sand, silt, and clay in the soil B) The soil’s pH level C) The amount of organic matter in the soil D) The soil’s color Answer: A) The proportion of sand, silt, and clay in the soil 35. What is ‘soil profile’? A) A vertical section of soil that displays all its horizons B) The surface layer of the soil C) The topsoil layer only D) The underground water table Answer: A) A vertical section of soil that displays all its horizons 36. Which process leads to the formation of ‘humus’? A) Decomposition of organic matter B) Soil erosion C) Soil compaction D) Soil leaching Answer: A) Decomposition of organic matter 37. What is ‘soil conservation’? A) The practice of preventing soil degradation and erosion B) The process of soil formation C) The addition of nutrients to the soil D) The removal of soil particles Answer: A) The practice of preventing soil degradation and erosion 38. Which soil type has the lowest water-holding capacity? A) Sand B) Clay C) Silt D) Loam Answer: A) Sand 39. What is the main cause of soil degradation? A) Unsustainable land management practices B) Natural weathering processes C) Increase in soil organic matter D) Soil aeration Answer: A) Unsustainable land management practices 40. Which soil horizon is often referred to as ‘bedrock’? A) Horizon C B) Horizon A C) Horizon B D) Horizon D Answer: A) Horizon C

Soil Science MCQs

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