Soils

Soil Soil is the lose covering of rock particles and decaying organic matter(humus) Results from both physical and chemical weathering

Parent Material Parent material is the source of the mineral matter in soils Parent material is important because: It affects the rate of weathering Chemical makeup affects the soils fertility

Time Time-The longer a soil has been forming the thicker it is. As a soil gets older other characteristics affect the soil more than the parent material

Climate Climate has the greatest affect on soil formation Variations in temperature and precipitation affect the rate, depth and type of weathering

Organisms Plants are the main source of organic matter Plants release nutrients when they decay. Adds to the soils fertility

Slope Steep slopes have higher erosion. Little water can soak in. Soils are thin on steep slopes

Characteristics of Soil Soil Texture Texture refers to the proportions of different particle sizes. A. Sand (large size) B. Silt – feels like flour C. Clay (small size) D. Loam (a mixture of all three sizes) is best suited for plant life.

Soil texture Soils are composed of particles that can be sand, silt or clay sized. Based on the soils % composition of each type of particle that determines the soils texture

Soil profile A soil profile is the vertical sequence of soil layers Soil horizons are the distinct layers in a profile The upper layers contain more organic material, the bottom layers contain more parent material