Soil & Earth's Crust

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Across
  1. 3. the healiest type of soil
  2. 4. name for different layers of soil such as topsoil being A
  3. 5. a factor in healthy soil made from rich organic matter
  4. 6. the term for the study of soil
Down
  1. 1. a practice to help prevent soil from becoming depleted
  2. 2. term for the top lyer of earths crust