Soil Nature’s dirty little secret

Soil is… July 22, 2012Footer text here2 Detritus from rock or - sand, Or silt and clay particles along with decomposed plant remains and live organisms. or The Loose surface of the earth that can support plants.

Composition – 4 Distinct Parts Mineral particles (45% of “typical” soil) Organic matter (about 5%) Water (about 25%) Air (about 25%) July 22, 2012Footer text here3

Importance Organisms, mainly microorganisms, inhabit the soil & depend on it for shelter, food & water. Plants anchor themselves into the soil, and get their nutrients and water. Terrestrial plants could not survive without soil, therefore, humans could not exist without soil either. July 22, 2012Footer text here4

SOIL: A RENEWABLE RESOURCE Soil is a slowly renewed resource that provides most of the nutrients needed for plant growth and also helps purify water. Soil formation begins when bedrock is broken down by physical, chemical and biological processes called weathering. Mature soils, or soils that have developed over a long time are arranged in a series of horizontal layers called soil horizons. July 22, 2012Footer text here5

Soil Formation Parent Material The rock that has slowly broken down into smaller particles by biological, chemical, and physical weathering. To form 2.5 cm (1 in.) it may take from years. July 22, 2012Footer text here6

Soil Is… July 22, 2012Footer text here7 The soil profile And the soil we pick up to feel consisting of sand, silt, clay particles and decomposed organic matter.

July 22, 2012 Footer text here 8 Soil texture is the single most important physical property of the soil. Knowing the soil texture alone will provide information about: 1) water flow potential, 2) water holding capacity, 3) fertility potential, 4) suitability for many urban uses.

Soil texture is determined by separating the amount of sand, silt and clay in a soil and determining the % of each. Different percentages of sand, silt and clay have been given “Textural Class Names” These 12 Names are put on a Textural Triangle for the various separate percentages July 22, 2012Footer text here9 Soil Texture…

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July 22, 2012Footer text here11 A sandy loam is a loam with the some characteristics of sand, while a loamy sand is a sand with some characteristics of a loam. (noun and adjective) ? Discuss two situations where you were aware of the soil’s texture. Sandy loam vs. loamy sand

Soil Structure Individual sand silt and clay particles will form together into specified shapes. These shaped structural peds – are given names based on their appearance. July 22, 2012Footer text here12 Peds are formed in the soil by wetting, drying, freezing and thawing and are held by clay and organic matter

Kinds of Soil Structure Granular Platy Sub-angular Blocky Prismatic Good structure promotes healthy soil July 22, 2012Footer text here13

Porosity A measure of the volume of soil and the average distances between the spaces. July 22, 2012Footer text here14

Permeability The rate at which water and air moves from upper to lower soil layers. It is distances between those spaces July 22, 2012Footer text here15

Some Soil Properties July 22, 2012Footer text here16 Soils vary in the size of the particles they contain, the amount of space between these particles, and how rapidly water flows through them.

July 22, 2012Footer text here –2 mm diameter Sand 0.002–0.05 mm diameter Silt less than mm Diameter Clay

For Today July 22, 2012Footer text here18 o Do the first four pages of your soil lab-through the Intro and Part I