Chapters 14 & 21 Super Seven: Soil Sciences Section; Selected, Stylized, Shrunk and Shown by Stephen Mauney and Holly Roberts

Definition of Soil The relatively thin surface layer of the Earth’s crust consisting of mineral and organic matter (humus). Soil isn’t dirt!! Dirt is only soil that is out of place. So when you are dirty it is misplaced but if you soil yourself it is in the right place.

1) The Five Soil Forming Factors Climate- Water, wind and temperature Biology- Macro/microorganisms and plants Relief- Topography Parent Material- Rocks and minerals it came from Time- The amount of time it took to form…

2) Porosity, Leaching and Illuviation Porosity- Amount of pore space in soil –~50% of soil volume Different combinations of air and water Leeching- The removal of dissolved materials from the soil as water percolates downward through pores Illuviation- Deposition of leeched materials in lower layers –Some materials leech completely out –Migrate down into ground water

3) Soil Horizons and Profile Soil Horizon- Distinctive later of soil Soil Profile- A vertical view of soil from surface to parent material, showing all present horizons. 1.O: Layer of organic Material 2.A: Topsoil- humus mixed with mineral grains 3.Leeched zone- (may be absent) 4.B:Subsoil- rich in clay, iron and aluminum 5.C :Weathered Bed rock 6.Bed Rock- Parent material

4) Physical Properties of Soil PropertySandSiltClay Water Holding LowMedium- High High AerationGoodMediumPoor Nutrient Supplying PoorMedium- High High Pollutant Filtering LowMediumHigh

Soil Types by Characteristic This should look familiar (but ours wasn’t such pretty colors). Each side line represents the soil’s percent of the component and you follow each line to the destination.

5) Chemical Properties of Soil pH –Most soil pH is 4-8, plants prefer 6-7 –Affects solubility of certain nutrients Low pH: Al & Mn are more soluble High pH: Some salts are less soluble –Soil conditioners Calcium Carbonate and Magnesium Carbonate correct soil acidity

6) Soil Pollution Definition- Any physical or chemical change in soil that adversely affects the health of plants and other organism living in and on it. Many Soil Pollutants –Mobile- move into groundwater, surface water and air –Persistent – seep in small cracks call microspores and stay in soil

7) Soil and Plant’s Relationship Salinization –Normal- salts create osmotic potential outside the root and the plant is in a turgid and healthy state –Too salty- the plant will lose water out of its roots Mycorrhizae- The relationship between nitrogen- fixing bacteria and plants roots. –Organism gives roots nitrogen –Roots use nitrogen to create food and gives some to the fixing organism.