1. It provides minerals and other nutrients for plants.
O = Litter
Horizon A = Topsoil = humus+ Loam (sand/silt/clay)
Horizon B = subsoil (clay/washed-down particles from Horizon A.
Horizon C = Bedrock , partly-weathered rock material
Soil – the loose, weathered material on Earth’s surface which plants can grow.
Litter – a loose layer of leaves and other plant material on top of the soil
Humus -decayed plant and animal remains
Soil horizon/profile – a layer of soil that differs from the layers above and below it
Loam – soil made up of equal parts of clay, sand and silt = the best mixture!
Decomposers – organisms that break down animal and plant remains and wastes
Leaching – drain away from soil/organic matter removed from soil or rock.
Why is soil valuable?????
It provides minerals and other nutrients for plants.
all animals get their energy from plants by either eating them or eating animals that have eaten plants.
It provides homes (habitats) for insects & animals.

2. WAYS PEOPLE HELP THE SOIL:
Conservation of soil - a method to maintain the fertility of the soil by protecting the soil from erosion and nutrient loss.
Contour plowing - forms ridges, slows the water flow and helps save precious topsoil.
Terraced farming - uses "steps" that are built into the side of a mountain or hill. Good for when the farmer does not have room for crops.
No-till farming -dead weeds and stalks are left in the ground from year to year to prevent wind /water erosion
Crop rotation - plant different crops in a field from year to year to slow nutrient depletion.
Cover crops – crops that are planted between harvests to replace the nutrients and keep the soil from eroding. (ex. Cabbage grown in the winter time)
WAYS SOIL LOSES FERTILITY & becomes useless:
Desertification – when dryland areas become even dryer from lack of rain & overuse by humans.
Erosion – when soil & sediments are carried away by wind, water or gravity.
Over-use – when humans farm too much, over-mining, building too much and over-watering.
Pollution – pollutants from mining, chemical spills, HUMANS