Land Subtopic 5.1

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Across
  1. 3. A system that releases more carbon than it absorbs.
  2. 7. Soil made up mostly of intermediate-sized particles, 0.002–0.05 mm in diameter.
  3. 9. matter Substances derived from living organisms, such as plant debris, faeces, or other carbon-based compounds.
  4. 11. A symbiotic relationship where both species benefit.
  5. 13. A state of very low biological activity, as in inactive seeds.
  6. 14. Movement of water into the soil from the surface.
  7. 15. The upper organic layer of soil rich in decomposing plant material.
  8. 16. Produced by or originating from human action.
  9. 22. Breakdown of organic molecules by living cells to release energy; can be aerobic or anaerobic.
  10. 24. Diffusion of gases into and out of soil, often increased by ploughing or burrowing animals.
  11. 30. Chemical reactions between rock minerals and water, oxygen, or acids.
  12. 31. Conversion of organic matter (humus) into mineral nutrients usable by plants.
  13. 32. A space between soil particles where air or water may be found.
  14. 35. A natural store of viable but dormant seeds within the soil.
  15. 37. A clump of soil formed when mineral particles stick together.
  16. 38. The subsoil, where materials like clay and minerals accumulate from above.
  17. 39. Thin, branching, thread-like structures of fungi.
  18. 40. Fungi forming mutualistic relationships with plant roots, exchanging minerals and water for sugars.
  19. 42. A cycle involving the movement and transformation of chemical elements through Earth’s systems.
  20. 44. The vertical section of soil showing all horizons and their characteristics.
  21. 46. An animal that eats detritus, breaking it into smaller pieces.
  22. 47. Movement of water through the soil layers.
  23. 48. A substance required by plants in small quantities, such as iron or zinc.
Down
  1. 1. A substance required by plants in large quantities, e.g., nitrogen, phosphorus, potassium.
  2. 2. Permanently frozen layer of soil that stores large amounts of organic carbon.
  3. 4. The process of salt accumulation in soil, usually due to excessive irrigation.
  4. 5. Soil made up of particles of various sizes and containing a significant percentage of organic matter.
  5. 6. Breakdown of rock by organisms such as lichens or plant roots.
  6. 8. matter Substances not derived from living organisms, usually from bedrock, air, or water.
  7. 10. A fluid secreted by a living organism, such as sugars or amino acids from plant roots.
  8. 12. The topsoil or mixed layer beneath the O horizon, rich in minerals and humus.
  9. 13. Biological breakdown of organic material into simpler substances.
  10. 17. Fully decomposed organic matter forming a dark, sticky material coating mineral particles.
  11. 18. Soil made up mostly of very fine particles, less than 0.002 mm in diameter.
  12. 19. The process of rocks breaking into smaller fragments by water, dissolved substances, organisms, or temperature changes.
  13. 20. Physical breakdown of rocks by freezing, thawing, heating, or abrasion.
  14. 21. Fine, wind-blown deposits of silt forming fertile soils in some regions.
  15. 23. A microorganism that breaks down organic matter by secreting enzymes and absorbing the products.
  16. 25. The rock that is broken down to provide the mineral components of a particular soil.
  17. 26. Partially decomposed organic matter.
  18. 27. The addition of harmful substances or pollutants to soil, intentionally or accidentally.
  19. 28. A symbiotic relationship where one species benefits and the other is harmed.
  20. 29. Involving or requiring oxygen; produces carbon dioxide.
  21. 30. A system that absorbs more carbon than it releases.
  22. 33. Occurring without oxygen; produces methane.
  23. 34. The lowest layer of soil, composed mainly of weathered parent material.
  24. 36. Downward movement of dissolved substances through soil with percolating water.
  25. 41. Partially decomposed organic matter accumulating in waterlogged soils.
  26. 43. Stony or rocky particles in soil larger than 2.0 mm in diameter.
  27. 44. Soil made up mostly of relatively large particles, from 0.05 to 2.0 mm in diameter.
  28. 45. Movement of broken-down rock particles from one place to another by agents like wind or water.