Soil Soil is made of A. weathered rock/ sediments B. humus- decayed plant and animal matter C- living organisms- (worms, fungi and insects)

Soil Horizons- layers of the soil A horizon- also called topsoil is made up of dead and decaying plants and animals. This layer is dark in color and rich in nutrients that are used by plants. B horizon- this layer is lighter in color because there is not any humus. Minerals are washed downward from the A horizon into this layer by a process called leaching. C horizon – this layer is the parent material containing mostly weathered rock or sediment

Soil profiles -side view of the different horizons (layers ) of soil in the ground.

Factors that affect soil formation Parent material- Type of vegetation- see next slide Slope of the land Climate Time

Notice the thicker darker top layer at the bottom of the slope