Soil

2. The process whereby pore spaces in well-drained sandy soil are filled with air
5. The proportion of clay, silt and sand contribute to which property of soil?
7. This provides plant nutrients, food for soil biota and increases water retention (4,7,6)
10. This can occur when rainfall is heavy or prolonged (7,6)
11. Whereby a field is divided with a criss-cross pattern of intersecting ridges (4,7)
12. The excessive use of heavy machinery can cause this
14. This occurs when livestock density is too high
15. Fertile layer of soil (3,4)
17. The primary force which enables soil to retain water (9,6)
18. The process whereby more than one crop is grown in a field at the same time
23. A series of narrow fields bordered by retaining walls and found on sloping land
24. Ploughing at 90 degrees to the slope angle (7,9)

1. The name given to the living organisms found in soil (4,5)
3. This can be used to estimate soil losses and assess the impacts of changes in farming techniques
4. Soil particles form aggregates called what?
6. A common feature of clay soils
8. Examples of these include worms, millipedes, woodlice and slugs
9. Another name for the pore spaces between soil particles (12,6)
13. This increases the fertility of soil where water is a limiting factor
16. Bacteria and fungi responsible for the breakdown of dead organic matter
19. This method minimises soil disturbance (4,7)
20. This can reduce the rate of soil erosion
21. Acidic soils can increase this, reducing the fertility
22. The name given to the expansion of deserts due to the erosion of soil