Humus is important because it makes the soil fertile.

Solve the crossword puzzle with the help of given clues.

ACROSS
1. The uppermost layer of the earth's crust. (4)
2. Breaking down of bigger rocks into smaller pieces by natural forces. (10)
3. The layer under the C-horizon. (7)
4. Property that affects the percolation of water through the soil. (8)
5. The layer just under the top layer. (7)
6. Soil that contains clay, silt, sand and humus in the right proportion. (5)
DOWN
7. The soil having the lowest water-retaining capacity. (5)
8. The soil having the highest water-retaining capacity. (6)
9. The layered structure of the soil. (11)