Sand Sand is tiny grains of worn down rock. It doesn’t hold water or have many nutrients.
Properties of Sand Color: white, tan, darker brown, an assortment Texture: gritty, coarse Capacity to retain water: water drains through sand quickly Ability to support plants: sand is not a fertile soil
Silt Silt is very small, broken pieces of rock. It is larger than clay, but smaller than sand. It is powdery when dry. Sand ------------Silt---------------Clay (larger particles)(smaller particles)
Properties of Silt Color: rich dark brown Texture: larger than clay, but smaller than sand; smooth and slippery when wet Capacity to retain water: retains water well Ability to support plants: fertile for plants
CLAY Clay holds water well. It is sticky and can be shaped when it is wet. But, it is very hard when dry. Clay has many nutrients. Clay is used for adobe or brick houses.
Properties of Clay Color: shades of gray Texture: sticky and plastic-like when wet; spreads into ribbons when squeezed; very fine texture Capacity to retain water: holds too much water, becomes water-logged & drowns plants Ability to support plants: not a fertile soil for plants
Humus Humus is made of leaves, twigs, small animals, or other decayed substances. Humus adds many nutrients to the soil. Humus is in the topsoil.
Formation of soils over time… Oldest Layers Youngest Layers
4 Layers of Soil 1.Undecayed Layer (The layer that contains the humus) 2.Topsoil (The layer on TOP) 3.Subsoil (The prefix SUB means under) 4.Bedrock (It’s hard as rock down there!) Undecayed Layer Oldest layers Youngest layers
Natural Resources Made by NATURE Cannot be replaced Must be conserved (saved)! When soil is left without anything holding it down, it can easily be washed away by erosion!
Ways to Conserve Soil Plant trees Plant grass Healthy farming Plant gardens to grow crops What else can you do to conserve soil? The plant’s roots hold the soil in place. This prevents water erosion!