Soil Components Melissa Morris

Four Major Components Organic Matter Water Air Mineral Materials Exist in a close mixed condition Interactions among components yields variation in environment for plant growth

Organic Matter An accumulation of plant and animal deposits Constantly being decomposed Small percentage of soil – 2-6% by weight Largely responsible for manageable characteristic of productive soil Source of soil nitrogen, sulfur and phosphorus Main source of energy for soil organisms

Water Is held in pore spaces between soil particles Soil water with its salts make up the soil solution Supplies nutrients to growing plants

Air Located in soil pores between soil particles These pores are the passageways for oxygen movement Aeration can be limited by water and compaction

Mineral Materials Variable in size and composition Remnants of parent material 4 sizes of Inorganic (mineral) particles  Gravel-very coarse  Sands-coarse  Silt-fine  Clay-very fine

Gravel Silt Sand Clay Images found at:

Soil Structure Particles group into aggregates CLAY helps bind  Too much clay will form a barrier to drainage SAND aids drainage and aeration  Too much sand causes water to drain too fast and makes soil dry out Different proportions of each will form different soil textures

Ideal soil composition Ideal soil is not too sandy or too much clay Excessive tillage destroys structure 45% sand, silt and clay mixture Pore spaces - 25% air and 25% water 5% organic matter

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Soil Categorization Categorized by finding % of each sand, silt, and clay Use soil triangle to find name % must add up to 100 ==================================== Find the name of a soil that is 25% sand, 45% silt, and 30% clay using the soil triangle.