Soils/ Soil & Water Relationships

1. Soils/ Soil & Water Relationships

2. The top few inches of the earth’s surface that supports plant growth. Formed from parent material (rocks and minerals) by a process known as weathering. Productivity can be lost by soil degradation, such as erosion and pollution. Soil

3. Four Principal Components of Soil 25% water 25% air 40-45% minerals 5-10% organic matter Organic matter is material made from living or once living material.

4. Soil is formed from parent material through a process called weathering. • Types of weathering are physical (mechanical) and chemical. • Mechanical/physical: • Plants & animals • Ice wedging • Chemical • water • Acids • oxygen Soil Formation

5. Climate Living organisms Parent material Time How the soil weathered Topography (the lay of the land) Factors that affect soil formation

6. Soil has three particle sizes: sand – the largest silt - medium clay – the smallest Soil Particles (separates)

7. Soil texture is the relative percentage of sand, silt, and clay in a soil sample. There are 12 soil textures. Different plants prefer different soil textures. Different textures have different relationships with water depending on the percentage of particles making up the soil. Scientists use the soil textural triangle to determine the soil’s texture. Soil Texture

9. Sedentary soils are weathered from large patches of bedrock, so they remain in place and don’t really move. Transported soils occur when particles are transported. colluvial- moved by gravity (landslide, mudslide) alluvial- moved by water (Delta, flood plains) aeolian- moved by wind glacial till- particles moved by glaciers Weathering results in particles

10. OM comes from living matter. Organic matter/humus Dark colored soils indicate greater amounts of OM. Benefits of OM in soil: Makes soil porous. Adds N and other nutrients to soil. Helps hold water. Furnishes food for living organisms. Minimizes leaching. Stabilizes soil structure. Examples of living contributions to soil: Roots Algae Fungi Small animals Insects Slugs Snails Worms Snakes reptiles Examples of non-living contributions to soil: Peat moss Leaf remnants Compost Grass clippings Saw dust manure

11. Soil Profile

12. The soil profile has at least 4 horizons or layers. *Leaching: when materials move through the soil profile; often materials like chemicals and pollutants are carried through the soil profile by water.

13. Soil structure: soil particles stick together to make 4 types of aggregates • Granular • Platy • Blocky • Prismatic/columnar • Wedge

15. Surface material and soil texture will determine how rapidly water flows through the soil profile. Water that fills up pore spaces between soil particles accumulate below the earth’s surface to create groundwater. Porosity is a measure of the amount of open space compared to the total volume of rock/soil. The ability of material to transmit fluid is permeability. Sandy soils have a greater porosity and therefore a greater permeability than clay and silt. Clay is the least porous and permeable. Water below the surface

16. Soil –Water relationships: permeability & drainability

18. Just below the surface is the zone of aeration. Below that is zone of saturation. Below the zone of saturation is the groundwater. The upper boundary of the zone of saturation is the water table. The depth of the groundwater/level of the water table varies with the precipitation and climate as well as what gets pumped out and used. It is essential that the amount pumped out does not exceed nature’s ability to recharge the water source. The Water table

19. The Water Table

20. An aquifer is any underground, water-bearing layer that groundwater can flow through. Aquitards confine the water. Aquifers